Installing a cluster on any platform

In OKD version 4.7, you can install a cluster on any infrastructure that you provision, including virtualization and cloud environments.

Prerequisites

• Review details about the OKD installation and update processes.

• If you use a firewall, you must configure it to allow the sites that your cluster requires access to.

  Be sure to also review this site list if you are configuring a proxy.

Machine requirements for a cluster with user-provisioned infrastructure

For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.

Required machines

The smallest OKD clusters require the following hosts:

• One temporary bootstrap machine

• Three control plane, or master, machines

• At least two compute machines, which are also known as worker machines.

The bootstrap and control plane machines must use Fedora CoreOS (FCOS) as the operating system. However, the compute machines can choose between Fedora CoreOS (FCOS) or Fedora 7.9.

See Red Hat Enterprise Linux technology capabilities and limits.

Network connectivity requirements

All the Fedora CoreOS (FCOS) machines require network in initramfs during boot to fetch Ignition config files from the Machine Config Server. During the initial boot, the machines require either a DHCP server or that static IP addresses be set in order to establish a network connection to download their Ignition config files. Additionally, each OKD node in the cluster must have access to a Network Time Protocol (NTP) server. If a DHCP server provides NTP servers information, the chrony time service on the Fedora CoreOS (FCOS) machines read the information and can sync the clock with the NTP servers.

Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

1. One vCPU is equivalent to one physical core when simultaneous multithreading (SMT), or hyperthreading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = vCPUs.

2. OKD and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.

Certificate signing requests management

Because your cluster has limited access to automatic machine management when you use infrastructure that you provision, you must provide a mechanism for approving cluster certificate signing requests (CSRs) after installation. The kube-controller-manager only approves the kubelet client CSRs. The machine-approver cannot guarantee the validity of a serving certificate that is requested by using kubelet credentials because it cannot confirm that the correct machine issued the request. You must determine and implement a method of verifying the validity of the kubelet serving certificate requests and approving them.

Creating the user-provisioned infrastructure

Before you deploy an OKD cluster that uses user-provisioned infrastructure, you must create the underlying infrastructure.

Prerequisites

• Review the OKD 4.x Tested Integrations page before you create the supporting infrastructure for your cluster.

Procedure

1. Configure DHCP or set static IP addresses on each node.

2. Provision the required load balancers.

3. Configure the ports for your machines.

4. Configure DNS.

5. Ensure network connectivity.

Networking requirements for user-provisioned infrastructure

All the Fedora CoreOS (FCOS) machines require network in initramfs during boot to fetch Ignition config from the machine config server.

During the initial boot, the machines require either a DHCP server or that static IP addresses be set on each host in the cluster to establish a network connection, which allows them to download their Ignition config files.

It is recommended to use the DHCP server to manage the machines for the cluster long-term. Ensure that the DHCP server is configured to provide persistent IP addresses and host names to the cluster machines.

The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.

You must configure the network connectivity between machines to allow cluster components to communicate. Each machine must be able to resolve the host names of all other machines in the cluster.

Network topology requirements

The infrastructure that you provision for your cluster must meet the following network topology requirements.

Load balancers

Before you install OKD, you must provision two load balancers that meet the following requirements:

1. API load balancer: Provides a common endpoint for users, both human and machine, to interact with and configure the platform. Configure the following conditions:

   • Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the API routes.

   • A stateless load balancing algorithm. The options vary based on the load balancer implementation.

   Do not configure session persistence for an API load balancer.

   Configure the following ports on both the front and back of the load balancers:

   Table 4. API load balancer

   Port	Back-end machines (pool members)	Internal	External	Description
   6443	Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane. You must configure the /readyz endpoint for the API server health check probe.	X	X	Kubernetes API server
   22623	Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane.	X		Machine config server

   The load balancer must be configured to take a maximum of 30 seconds from the time the API server turns off the /readyz endpoint to the removal of the API server instance from the pool. Within the time frame after /readyz returns an error or becomes healthy, the endpoint must have been removed or added. Probing every 5 or 10 seconds, with two successful requests to become healthy and three to become unhealthy, are well-tested values.

2. Application Ingress load balancer: Provides an Ingress point for application traffic flowing in from outside the cluster. Configure the following conditions:

   • Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the Ingress routes.

   • A connection-based or session-based persistence is recommended, based on the options available and types of applications that will be hosted on the platform.

   Configure the following ports on both the front and back of the load balancers:

   Table 5. Application Ingress load balancer

   Port	Back-end machines (pool members)	Internal	External	Description
   443	The machines that run the Ingress router pods, compute, or worker, by default.	X	X	HTTPS traffic
   80	The machines that run the Ingress router pods, compute, or worker, by default.	X	X	HTTP traffic

NTP configuration

OKD clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.

If a DHCP server provides NTP server information, the chrony time service on the Fedora CoreOS (FCOS) machines read the information and can sync the clock with the NTP servers.

Additional resources

• Configuring chrony time service

User-provisioned DNS requirements

DNS is used for name resolution and reverse name resolution. DNS A/AAAA or CNAME records are used for name resolution and PTR records are used for reverse name resolution. The reverse records are important because Fedora CoreOS (FCOS) uses the reverse records to set the host name for all the nodes. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OKD needs to operate.

The following DNS records are required for an OKD cluster that uses user-provisioned infrastructure. In each record, <cluster_name> is the cluster name and <base_domain> is the cluster base domain that you specify in the install-config.yaml file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>..

The following example of a BIND zone file shows sample A records for name resolution. The purpose of the example is to show the records that are needed. The example is not meant to provide advice for choosing one name resolution service over another.

Sample DNS zone database

$TTL 1W
@    IN    SOA    ns1.example.com.    root (
            2019070700    ; serial
            3H        ; refresh (3 hours)
            30M        ; retry (30 minutes)
            2W        ; expiry (2 weeks)
            1W )        ; minimum (1 week)
    IN    NS    ns1.example.com.
    IN    MX 10    smtp.example.com.
;
;
ns1    IN    A    192.168.1.5
smtp    IN    A    192.168.1.5
;
helper    IN    A    192.168.1.5
helper.ocp4    IN    A    192.168.1.5
;
; The api identifies the IP of your load balancer.
api.ocp4        IN    A    192.168.1.5
api-int.ocp4        IN    A    192.168.1.5
;
; The wildcard also identifies the load balancer.
*.apps.ocp4        IN    A    192.168.1.5
;
; Create an entry for the bootstrap host.
bootstrap.ocp4    IN    A    192.168.1.96
;
; Create entries for the master hosts.
master0.ocp4        IN    A    192.168.1.97
master1.ocp4        IN    A    192.168.1.98
master2.ocp4        IN    A    192.168.1.99
;
; Create entries for the worker hosts.
worker0.ocp4        IN    A    192.168.1.11
worker1.ocp4        IN    A    192.168.1.7
;
;EOF

The following example BIND zone file shows sample PTR records for reverse name resolution.

Sample DNS zone database for reverse records

$TTL 1W
@    IN    SOA    ns1.example.com.    root (
            2019070700    ; serial
            3H        ; refresh (3 hours)
            30M        ; retry (30 minutes)
            2W        ; expiry (2 weeks)
            1W )        ; minimum (1 week)
    IN    NS    ns1.example.com.
;
; The syntax is "last octet" and the host must have an FQDN
; with a trailing dot.
97    IN    PTR    master0.ocp4.example.com.
98    IN    PTR    master1.ocp4.example.com.
99    IN    PTR    master2.ocp4.example.com.
;
96    IN    PTR    bootstrap.ocp4.example.com.
;
5    IN    PTR    api.ocp4.example.com.
5    IN    PTR    api-int.ocp4.example.com.
;
11    IN    PTR    worker0.ocp4.example.com.
7    IN    PTR    worker1.ocp4.example.com.
;
;EOF

Generating an SSH private key and adding it to the agent

If you want to perform installation debugging or disaster recovery on your cluster, you must provide an SSH key to both your ssh-agent and the installation program. You can use this key to access the bootstrap machine in a public cluster to troubleshoot installation issues.

You can use this key to SSH into the master nodes as the user core. When you deploy the cluster, the key is added to the core user’s ~/.ssh/authorized_keys list.

Procedure

1. If you do not have an SSH key that is configured for password-less authentication on your computer, create one. For example, on a computer that uses a Linux operating system, run the following command:

   $ ssh-keygen -t ed25519 -N '' \
       -f <path>/<file_name> (1)

   1	Specify the path and file name, such as ~/.ssh/id_rsa, of the new SSH key. If you have an existing key pair, ensure your public key is in the your ~/.ssh directory.

   Running this command generates an SSH key that does not require a password in the location that you specified.

   If you plan to install an OKD cluster that uses FIPS Validated / Modules in Process cryptographic libraries on the x86_64 architecture, do not create a key that uses the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.

2. Start the ssh-agent process as a background task:

   $ eval "$(ssh-agent -s)"

   Example output

   Agent pid 31874

   If your cluster is in FIPS mode, only use FIPS-compliant algorithms to generate the SSH key. The key must be either RSA or ECDSA.

3. Add your SSH private key to the ssh-agent:

   $ ssh-add <path>/<file_name> (1)

   Example output

   Identity added: /home/<you>/<path>/<file_name> (<computer_name>)

   1	Specify the path and file name for your SSH private key, such as ~/.ssh/id_rsa

Next steps

• When you install OKD, provide the SSH public key to the installation program. If you install a cluster on infrastructure that you provision, you must provide this key to your cluster’s machines.

Obtaining the installation program

Before you install OKD, download the installation file on a local computer.

Prerequisites

• You have a computer that runs Linux or macOS, with 500 MB of local disk space

Procedure

1. Download installer from https://github.com/openshift/okd/releases

   The installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.

   Deleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OKD uninstallation procedures for your specific cloud provider.

2. Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:

   $ tar xvf openshift-install-linux.tar.gz

3. From the Pull Secret page on the Red Hat OpenShift Cluster Manager site, download your installation pull secret as a .txt file. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OKD components.

   Using a pull secret from the Red Hat OpenShift Cluster Manager site is not required. You can use a pull secret for another private registry. Or, if you do not need the cluster to pull images from a private registry, you can use {"auths":{"fake":{"auth":"aWQ6cGFzcwo="}}} as the pull secret when prompted during the installation.

   If you do not use the pull secret from the Red Hat OpenShift Cluster Manager site:

   • Red Hat Operators are not available.

   • The Telemetry and Insights operators do not send data to Red Hat.

   • Content from the Red Hat Container Catalog registry, such as image streams and Operators, are not available.

Installing the OpenShift CLI by downloading the binary

You can install the OpenShift CLI (oc) to interact with OKD from a command-line interface. You can install oc on Linux, Windows, or macOS.

Installing the OpenShift CLI on Linux

You can install the OpenShift CLI (oc) binary on Linux by using the following procedure.

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.tar.gz.

3. Unpack the archive:

   $ tar xvzf <file>

4. Place the oc binary in a directory that is on your PATH.

   To check your PATH, execute the following command:

   $ echo $PATH

After you install the OpenShift CLI, it is available using the oc command:

$ oc <command>

Installing the OpenShift CLI on Windows

You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.zip.

3. Unzip the archive with a ZIP program.

4. Move the oc binary to a directory that is on your PATH.

   To check your PATH, open the command prompt and execute the following command:

   C:\> path

After you install the OpenShift CLI, it is available using the oc command:

C:\> oc <command>

Installing the OpenShift CLI on macOS

You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.tar.gz.

3. Unpack and unzip the archive.

4. Move the oc binary to a directory on your PATH.

   To check your PATH, open a terminal and execute the following command:

   $ echo $PATH

After you install the OpenShift CLI, it is available using the oc command:

$ oc <command>

Manually creating the installation configuration file

For installations of OKD that use user-provisioned infrastructure, you manually generate your installation configuration file.

Prerequisites

• Obtain the OKD installation program and the access token for your cluster.

Procedure

1. Create an installation directory to store your required installation assets in:

   $ mkdir <installation_directory>

   You must create a directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OKD version.

2. Customize the following install-config.yaml file template and save it in the <installation_directory>.

   You must name this configuration file install-config.yaml.

3. Back up the install-config.yaml file so that you can use it to install multiple clusters.

   The install-config.yaml file is consumed during the next step of the installation process. You must back it up now.

Sample install-config.yaml file for other platforms

You can customize the install-config.yaml file to specify more details about your OKD cluster’s platform or modify the values of the required parameters.

apiVersion: v1
baseDomain: example.com (1)
compute: (2)
- hyperthreading: Enabled (3)
  name: worker
  replicas: 0 (4)
controlPlane: (2)
  hyperthreading: Enabled (3)
  name: master
  replicas: 3 (5)
metadata:
  name: test (6)
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14 (7)
    hostPrefix: 23 (8)
  networkType: OVNKubernetes
  serviceNetwork: (9)
  - 172.30.0.0/16
platform:
  none: {} (10)
pullSecret: '{"auths": ...}' (11)
sshKey: 'ssh-ed25519 AAAA...' (12)

Configuring the cluster-wide proxy during installation

Production environments can deny direct access to the Internet and instead have an HTTP or HTTPS proxy available. You can configure a new OKD cluster to use a proxy by configuring the proxy settings in the install-config.yaml file.

Prerequisites

• You have an existing install-config.yaml file.

• You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the Proxy object’s spec.noProxy field to bypass the proxy if necessary.

  The Proxy object status.noProxy field is populated with the values of the networking.machineNetwork[].cidr, networking.clusterNetwork[].cidr, and networking.serviceNetwork[] fields from your installation configuration. For installations on Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the Proxy object status.noProxy field is also populated with the instance metadata endpoint (169.254.169.254).

• If your cluster is on AWS, you added the ec2.<region>.amazonaws.com, elasticloadbalancing.<region>.amazonaws.com, and s3.<region>.amazonaws.com endpoints to your VPC endpoint. These endpoints are required to complete requests from the nodes to the AWS EC2 API. Because the proxy works on the container level, not the node level, you must route these requests to the AWS EC2 API through the AWS private network. Adding the public IP address of the EC2 API to your allowlist in your proxy server is not sufficient.

Procedure

1. Edit your install-config.yaml file and add the proxy settings. For example:

   apiVersion: v1
   baseDomain: my.domain.com
   proxy:
     httpProxy: http://<username>:<pswd>@<ip>:<port> (1)
     httpsProxy: https://<username>:<pswd>@<ip>:<port> (2)
     noProxy: example.com (3)
   additionalTrustBundle: | (4)
       -----BEGIN CERTIFICATE-----
       <MY_TRUSTED_CA_CERT>
       -----END CERTIFICATE-----
   ...

   1	A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be http. If you use an MITM transparent proxy network that does not require additional proxy configuration but requires additional CAs, you must not specify an httpProxy value.
   2	A proxy URL to use for creating HTTPS connections outside the cluster. If you use an MITM transparent proxy network that does not require additional proxy configuration but requires additional CAs, you must not specify an httpsProxy value.
   3	A comma-separated list of destination domain names, domains, IP addresses, or other network CIDRs to exclude proxying. Preface a domain with . to match subdomains only. For example, .y.com matches x.y.com, but not y.com. Use * to bypass proxy for all destinations.
   4	If provided, the installation program generates a config map that is named user-ca-bundle in the openshift-config namespace that contains one or more additional CA certificates that are required for proxying HTTPS connections. The Cluster Network Operator then creates a trusted-ca-bundle config map that merges these contents with the Fedora CoreOS (FCOS) trust bundle, and this config map is referenced in the Proxy object’s trustedCA field. The additionalTrustBundle field is required unless the proxy’s identity certificate is signed by an authority from the FCOS trust bundle. If you use an MITM transparent proxy network that does not require additional proxy configuration but requires additional CAs, you must provide the MITM CA certificate.

   The installation program does not support the proxy readinessEndpoints field.

2. Save the file and reference it when installing OKD.

The installation program creates a cluster-wide proxy that is named cluster that uses the proxy settings in the provided install-config.yaml file. If no proxy settings are provided, a cluster Proxy object is still created, but it will have a nil spec.

Configuring a three-node cluster

You can optionally install and run three-node clusters in OKD with no workers. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for development, production, and testing.

Procedure

• Edit the install-config.yaml file to set the number of compute replicas, which are also known as worker replicas, to 0, as shown in the following compute stanza:

  compute:
  - name: worker
    platform: {}
    replicas: 0

Creating the Kubernetes manifest and Ignition config files

Because you must modify some cluster definition files and manually start the cluster machines, you must generate the Kubernetes manifest and Ignition config files that the cluster needs to make its machines.

The installation configuration file transforms into the Kubernetes manifests. The manifests wrap into the Ignition configuration files, which are later used to create the cluster.

Prerequisites

• You obtained the OKD installation program.

• You created the install-config.yaml installation configuration file.

Procedure

1. Change to the directory that contains the installation program and generate the Kubernetes manifests for the cluster:

   $ ./openshift-install create manifests --dir=<installation_directory> (1)

   Example output

   INFO Credentials loaded from the "myprofile" profile in file "/home/myuser/.aws/credentials"
   INFO Consuming Install Config from target directory
   INFO Manifests created in: install_dir/manifests and install_dir/openshift

   1	For <installation_directory>, specify the installation directory that contains the install-config.yaml file you created.

1. Check that the mastersSchedulable parameter in the <installation_directory>/manifests/cluster-scheduler-02-config.yml Kubernetes manifest file is set to false. This setting prevents pods from being scheduled on the control plane machines:

   1. Open the <installation_directory>/manifests/cluster-scheduler-02-config.yml file.

   2. Locate the mastersSchedulable parameter and ensure that it is set to false.

   3. Save and exit the file.

2. To create the Ignition configuration files, run the following command from the directory that contains the installation program:

   $ ./openshift-install create ignition-configs --dir=<installation_directory> (1)

   1	For <installation_directory>, specify the same installation directory.

   The following files are generated in the directory:

   .
   ├── auth
   │   ├── kubeadmin-password
   │   └── kubeconfig
   ├── bootstrap.ign
   ├── master.ign
   ├── metadata.json
   └── worker.ign

Creating Fedora CoreOS (FCOS) machines

Before you install a cluster on infrastructure that you provision, you must create FCOS machines for it to use. If your infrastructure supports it, create the machines by following either the steps to use an ISO image or network PXE booting. In some cases, you might be able to upload an appropriate FCOS image from the Product Downloads page on the Red Hat Customer Portal or the FCOS image mirror to your cloud provider and use that image to create the machines.

There are several methods of configuring FCOS during ISO and PXE installations. These include:

• Kernel arguments: For a PXE install, you can APPEND arguments to the kernel of the live installer. For an ISO install, you can interrupt the live installation boot process to add kernel arguments. In both cases, you can use special coreos.inst.* arguments to direct the live installer, as well as standard installation boot arguments for turning standard kernel services on or off.

• Ignition configs: You must generate an OKD Ignition config file (*.ign) for the type of node you are installing (worker, control plane, or bootstrap). You pass the location of the Ignition config to the installed system so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by the installer and should not be used to include the standard worker and master Ignition configs.

• coreos-installer: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run the coreos-installer command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.

Whether to use an ISO or PXE install depends on your situation. A PXE install requires an available DHCP service and more preparation, but can make the installation process more automated. An ISO install is a more manual process and can be inconvenient if you are setting up more than a few machines.

Creating Fedora CoreOS (FCOS) machines using an ISO image

Before you install a cluster on infrastructure that you provision, you must create FCOS machines for it to use. You can use an ISO image to create the machines.

Prerequisites

• Obtain the Ignition config files for your cluster.

• Have access to an HTTP server that can be accessed from your computer, and from the machines that you create.

Procedure

1. Upload the control plane, compute, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.

   If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

2. Obtain the FCOS images from the FCOS Downloads page

3. Use the ISO to start the FCOS installation. Use one of the following installation options:

   • Burn the ISO image to a disk and boot it directly.

   • Use ISO redirection via a LOM interface.

4. Boot the ISO image. You can interrupt the installation boot process to add kernel arguments. However, for this ISO procedure you should use the coreos-installer command instead of adding kernel arguments. If you run the live installer without options or interruption, the installer boots up to a shell prompt on the live system, ready for you to install FCOS to disk.

5. Review the Advanced FCOS installation reference section for different ways of configuring features, such as networking and disk partitions, before running the coreos-installer.

6. Run the coreos-installer command. At a minimum, you must identify the Ignition config file location for your node type, and the location of the disk you are installing to. Here is an example:

   $ sudo coreos-installer install \
        --ignition-url=https://host/worker.ign /dev/sda

7. After FCOS installs, the system reboots. During the system reboot, it applies the Ignition config file that you specified.

8. Continue to create the other machines for your cluster.

   You must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, which is the default, also create at least two compute machines before you install the cluster.

Creating Fedora CoreOS (FCOS) machines by PXE or iPXE booting

Before you install a cluster that uses manually-provisioned FCOS nodes, such as bare metal, you must create FCOS machines for it to use. You can use PXE or iPXE booting to create the machines.

Prerequisites

• Obtain the Ignition config files for your cluster.

• Configure suitable PXE or iPXE infrastructure.

• Have access to an HTTP server that you can access from your computer.

Procedure

1. Upload the master, worker, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.

   You can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

2. Obtain the FCOS kernel, initramfs and rootfs files from the FCOS Downloads page

3. Upload the additional files that are required for your booting method:

   • For traditional PXE, upload the kernel and initramfs files to your TFTP server and the rootfs file to your HTTP server.

   • For iPXE, upload the kernel, initramfs, and rootfs files to your HTTP server.

     If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

4. Configure the network boot infrastructure so that the machines boot from their local disks after FCOS is installed on them.

5. Configure PXE or iPXE installation for the FCOS images.

   Modify one of the following example menu entries for your environment and verify that the image and Ignition files are properly accessible:

   • For PXE:

     DEFAULT pxeboot
     TIMEOUT 20
     PROMPT 0
     LABEL pxeboot
         KERNEL http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> (1)
         APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign (2) (3)

     1	Specify the location of the live kernel file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported.
     2	If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
     3	Specify locations of the FCOS files that you uploaded to your HTTP server. The initrd parameter value is the location of the initramfs file, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to the APPEND line to configure networking or other boot options.

     This configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more console= arguments to the APPEND line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux?.

   • For iPXE:

     kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign (1) (2)
     initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img (3)
     boot

     1	Specify locations of the FCOS files that you uploaded to your HTTP server. The kernel parameter value is the location of the kernel file, the initrd=main argument is needed for booting on UEFI systems, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file.
     2	If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
     3	Specify the location of the initramfs file that you uploaded to your HTTP server.

     This configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more console= arguments to the kernel line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux?.

6. If you use PXE UEFI, perform the following actions:

   1. Provide the shimx64.efi and grubx64.efi EFI binaries and the grub.cfg file that are required for booting the system.

      • Extract the necessary EFI binaries by mounting the FCOS ISO to your host and then mounting the images/efiboot.img file to your host:

        $ mkdir -p /mnt/iso

        $ mkdir -p /mnt/efiboot

        $ mount -o loop rhcos-installer.x86_64.iso /mnt/iso

        $ mount -o loop,ro /mnt/iso/images/efiboot.img /mnt/efiboot

      • From the efiboot.img mount point, copy the EFI/redhat/shimx64.efi and EFI/redhat/grubx64.efi files to your TFTP server:

        $ cp /mnt/efiboot/EFI/redhat/shimx64.efi .

        $ cp /mnt/efiboot/EFI/redhat/grubx64.efi .

        $ umount /mnt/efiboot

        $ umount /mnt/iso

      • Copy the EFI/redhat/grub.cfg file that is included in the FCOS ISO to your TFTP server.

   2. Edit the grub.cfg file to include arguments similar to the following:

      menuentry 'Install Red Hat Enterprise Linux CoreOS' --class fedora --class gnu-linux --class gnu --class os {
          linuxefi rhcos-<version>-live-kernel-<architecture> coreos.inst.install_dev=/dev/sda coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign
          initrdefi rhcos-<version>-live-initramfs.<architecture>.img
      }

      where:

      rhcos-<version>-live-kernel-<architecture>

      Specifies the kernel file that you uploaded to your TFTP server.

      http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img

      Specifies the location of the live rootfs image that you uploaded to your HTTP server.

      http://<HTTP_server>/bootstrap.ign

      Specifies the location of the bootstrap Ignition config file that you uploaded to your HTTP server.

      rhcos-<version>-live-initramfs.<architecture>.img

      Specifies the location of the initramfs file that you uploaded to your TFTP server.

      For more information on how to configure a PXE server for UEFI boot, see the Red Hat Knowledgebase article: How to configure/setup a PXE server for UEFI boot for Red Hat Enterprise Linux?.

7. Continue to create the machines for your cluster.

   You must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, which is the default, also create at least two compute machines before you install the cluster.

Advanced Fedora CoreOS (FCOS) installation configuration

A key benefit for manually provisioning the Fedora CoreOS (FCOS) nodes for OKD is to be able to do configuration that is not available through default OKD installation methods. This section describes some of the configurations that you can do using techniques that include:

• Passing kernel arguments to the live installer

• Running coreos-installer manually from the live system

• Embedding Ignition configs in an ISO

The advanced configuration topics for manual Fedora CoreOS (FCOS) installations detailed in this section relate to disk partitioning, networking, and using Ignition configs in different ways.

Using advanced networking options for PXE and ISO installations

Networking for OKD nodes uses DHCP by default to gather all necessary configuration settings. To set up static IP addresses or configure special settings, such as bonding, you can do one of the following:

• Pass special kernel parameters when you boot the live installer.

• Use a machine config to copy networking files to the installed system.

• Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.

To configure a PXE or iPXE installation, use one of the following options:

• See the “Advanced RHCOS installation reference” tables.

• Use a machine config to copy networking files to the installed system.

To configure an ISO installation, use the following procedure.

Procedure

1. Boot the ISO installer.

2. From the live system shell prompt, configure networking for the live system using available RHEL tools, such as nmcli or nmtui.

3. Run the coreos-installer command to install the system, adding the --copy-network option to copy networking configuration. For example:

   $ coreos-installer install --copy-network \
        --ignition-url=http://host/worker.ign /dev/sda

   The —copy-network option only copies networking configuration found under /etc/NetworkManager/system-connections. In particular, it does not copy the system hostname.

4. Reboot into the installed system.

Disk partitioning

The disk partitions are created on OKD cluster nodes during the Fedora CoreOS (FCOS) installation. Each FCOS node of a particular architecture uses the same partition layout, unless the default partitioning configuration is overridden. During the FCOS installation, the size of the root file system is increased to use the remaining available space on the target device.

However, there are two cases where you might want to intervene to override the default partitioning when installing an OKD node:

• Create separate partitions: For greenfield installations on an empty disk, you might want to add separate storage to a partition. This is officially supported for making /var or a subdirectory of /var, such as /var/lib/etcd, a separate partition, but not both.

  Kubernetes supports only two filesystem partitions. If you add more than one partition to the original configuration, Kubernetes cannot monitor all of them.

• Retain existing partitions: For a brownfield installation where you are reinstalling OKD on an existing node and want to retain data partitions installed from your previous operating system, there are both boot arguments and options to coreos-installer that allow you to retain existing data partitions.

Creating a separate /var partition

In general, disk partitioning for OKD should be left to the installer. However, there are cases where you might want to create separate partitions in a part of the filesystem that you expect to grow.

OKD supports the addition of a single partition to attach storage to either the /var partition or a subdirectory of /var. For example:

• /var/lib/containers: Holds container-related content that can grow as more images and containers are added to a system.

• /var/lib/etcd: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage.

• /var: Holds data that you might want to keep separate for purposes such as auditing.

Storing the contents of a /var directory separately makes it easier to grow storage for those areas as needed and reinstall OKD at a later date and keep that data intact. With this method, you will not have to pull all your containers again, nor will you have to copy massive log files when you update systems.

Because /var must be in place before a fresh installation of Fedora CoreOS (FCOS), the following procedure sets up the separate /var partition by creating a machine config that is inserted during the openshift-install preparation phases of an OKD installation.

Procedure

1. Create a directory to hold the OKD installation files:

   $ mkdir $HOME/clusterconfig

2. Run openshift-install to create a set of files in the manifest and openshift subdirectories. Answer the system questions as you are prompted:

   $ openshift-install create manifests --dir $HOME/clusterconfig
   ? SSH Public Key ...
   $ ls $HOME/clusterconfig/openshift/
   99_kubeadmin-password-secret.yaml
   99_openshift-cluster-api_master-machines-0.yaml
   99_openshift-cluster-api_master-machines-1.yaml
   99_openshift-cluster-api_master-machines-2.yaml
   ...

3. Create a MachineConfig object and add it to a file in the openshift directory. For example, name the file 98-var-partition.yaml, change the disk device name to the name of the storage device on the worker systems, and set the storage size as appropriate. This attaches storage to a separate /var directory.

   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfig
   metadata:
     labels:
       machineconfiguration.openshift.io/role: worker
     name: 98-var-partition
   spec:
     config:
       ignition:
         version: 3.2.0
       storage:
         disks:
         - device: /dev/<device_name> (1)
           partitions:
           - sizeMiB: <partition_size>
             startMiB: <partition_start_offset> (2)
             label: var
         filesystems:
           - path: /var
             device: /dev/disk/by-partlabel/var
             format: xfs
       systemd:
         units:
           - name: var.mount
             enabled: true
             contents: |
               [Unit]
               Before=local-fs.target
               [Mount]
               Where=/var
               What=/dev/disk/by-partlabel/var
               [Install]
               WantedBy=local-fs.target

   1

   The storage device name of the disk that you want to partition.

   2

   When adding a data partition to the boot disk, a minimum value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of FCOS might overwrite the beginning of the data partition.

   When creating a separate /var partition, you cannot use different instance types for worker nodes, if the different instance types do not have the same device name.

4. Run openshift-install again to create Ignition configs from a set of files in the manifest and openshift subdirectories:

   $ openshift-install create ignition-configs --dir $HOME/clusterconfig
   $ ls $HOME/clusterconfig/
   auth  bootstrap.ign  master.ign  metadata.json  worker.ign

Now you can use the Ignition config files as input to the ISO or PXE manual installation procedures to install Fedora CoreOS (FCOS) systems.

Retaining existing partitions

For an ISO installation, you can add options to the coreos-installer command line that causes the installer to maintain one or more existing partitions. For a PXE installation, you can APPEND coreos.inst.* options to preserve partitions.

Saved partitions might be partitions from an existing OKD system that has data partitions that you want to keep. Here are a few tips:

• If you save existing partitions, and those partitions do not leave enough space for FCOS, installation will fail without damaging the saved partitions.

• Identify the disk partitions you want to keep either by partition label or by number.

For an ISO installation

This example preserves any partition in which the partition label begins with data (data*):

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partlabel 'data*' /dev/sda

The following example illustrates running the coreos-installer in a way that preserves the sixth (6) partition on the disk:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partindex 6 /dev/sda

This example preserves partitions 5 and higher:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign
        --save-partindex 5- /dev/sda

In the previous examples where partition saving is used, coreos-installer recreates the partition immediately.

For a PXE installation

This APPEND option preserves any partition in which the partition label begins with ‘data’ (‘data*‘):

coreos.inst.save_partlabel=data*

This APPEND option preserves partitions 5 and higher:

coreos.inst.save_partindex=5-

This APPEND option preserves partition 6:

coreos.inst.save_partindex=6

Identifying Ignition configs

When doing an FCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:

• Permanent install Ignition config: Every manual FCOS installation needs to pass one of the Ignition config files generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, to carry out the installation.

  It is not recommended to modify these files.

  For PXE installations, you pass the Ignition configs on the APPEND line using the coreos.inst.ignition_url= option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on the coreos-installer command line with the --ignition-url= option. In both cases, only HTTP and HTTPS protocols are supported.

• Live install Ignition config: This type must be created manually and should be avoided if possible, as it is not supported by Red Hat. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before and/or after the FCOS system installs to disk. This method should only be used for performing tasks that must be performed once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.

  For PXE or ISO boots, you can create the Ignition config and APPEND the ignition.config.url= option to identify the location of the Ignition config. You also need to append ignition.firstboot ignition.platform.id=metal or the ignition.config.url option will be ignored.

Embedding an Ignition config in the FCOS ISO

You can embed a live install Ignition config directly in an FCOS ISO image. When the ISO image is booted, the embedded config will be applied automatically.

Procedure

1. Download the coreos-installer binary from the following image mirror page: https://mirror.openshift.com/pub/openshift-v4/clients/coreos-installer/latest/.

2. Retrieve the FCOS ISO image and the Ignition config file, and copy them into an accessible directory, such as /mnt:

   # cp rhcos-<version>-live.x86_64.iso bootstrap.ign /mnt/
   # chmod 644 /mnt/rhcos-<version>-live.x86_64.iso

3. Run the following command to embed the Ignition config into the ISO:

   # ./coreos-installer iso ignition embed -i /mnt/bootstrap.ign \
        /mnt/rhcos-<version>-live.x86_64.iso

   You can now use that ISO to install FCOS using the specified live install Ignition config.

   Using coreos-installer iso ignition embed to embed a file generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, is unsupported and not recommended.

4. To show the contents of the embedded Ignition config and direct it into a file, run:

   # ./coreos-installer iso ignition show /mnt/rhcos-<version>-live.x86_64.iso > mybootstrap.ign

   # diff -s bootstrap.ign mybootstrap.ign

   Example output

   Files bootstrap.ign and mybootstrap.ign are identical

5. To remove the Ignition config and return the ISO to its pristine state so you can reuse it, run:

   # ./coreos-installer iso ignition remove /mnt/rhcos-<version>-live.x86_64.iso

   You can now embed another Ignition config into the ISO or use the ISO in its pristine state.

Advanced FCOS installation reference

This section illustrates the networking configuration and other advanced options that allow you to modify the Fedora CoreOS (FCOS) manual installation process. The following tables describe the kernel arguments and command-line options you can use with the FCOS live installer and the coreos-installer command.

Routing and bonding options at FCOS boot prompt

If you install FCOS from an ISO image, you can add kernel arguments manually when you boot that image to configure the node’s networking. If no networking arguments are used, the installation defaults to using DHCP.

The following table describes how to use ip=, nameserver=, and bond= kernel arguments for live ISO installs.

Routing and bonding options for ISO

The following table provides examples for configuring networking of your Fedora CoreOS (FCOS) nodes. These are networking options that are passed to the dracut tool during system boot. For more information about the networking options supported by dracut, see the dracut.cmdline manual page.

ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
nameserver=4.4.4.41

ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none

ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
ip=::::core0.example.com:enp2s0:none

ip=enp1s0:dhcp
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none

ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none
vlan=enp2s0.100:enp2s0

ip=enp2s0.100:dhcp
vlan=enp2s0.100:enp2s0

nameserver=1.1.1.1
nameserver=8.8.8.8

bond=bond0:em1,em2:mode=active-backup
ip=bond0:dhcp

bond=bond0:em1,em2:mode=active-backup
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none

ip=bond0.100:dhcp
bond=bond0:em1,em2:mode=active-backup
vlan=bond0.100:bond0

ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0.100:none
bond=bond0:em1,em2:mode=active-backup
vlan=bond0.100:bond0

coreos.inst boot options for ISO or PXE install

While you can pass most standard installation boot arguments to the live installer, there are several arguments that are specific to the FCOS live installer.

• For ISO, these options can be added by interrupting the FCOS installer.

• For PXE or iPXE, these options must be added to the APPEND line before starting the PXE kernel. You cannot interrupt a live PXE install.

The following table shows the FCOS live installer boot options for ISO and PXE installs.

coreos-installer options for ISO install

You can also install FCOS by invoking the coreos-installer command directly from the command line. The kernel arguments in the previous table provide a shortcut for automatically invoking coreos-installer at boot time, but you can pass similar arguments directly to coreos-installer when running it from a shell prompt.

The following table shows the options and subcommands you can pass to the coreos-installer command from a shell prompt during a live install.

Updating the bootloader using bootupd

To update the bootloader by using bootupd, you must either install bootupd on FCOS machines manually or provide a machine config with the enabled systemd unit. Unlike grubby or other bootloader tools, bootupd does not manage kernel space configuration such as passing kernel arguments.

After you have installed bootupd, you can manage it remotely from the OKD cluster.

Manual install method

You can manually install bootupd by using the bootctl command-line tool.

1. Inspect the system status:

   # bootupctl status

   Example output

   Component EFI
     Installed: grub2-efi-x64-1:2.04-31.fc33.x86_64,shim-x64-15-8.x86_64
     Update: At latest version

2. FCOS images created without bootupd installed on them require an explicit adoption phase.

   If the system status is Adoptable, perform the adoption:

   # bootupctl adopt-and-update

   Example output

   Updated: grub2-efi-x64-1:2.04-31.fc33.x86_64,shim-x64-15-8.x86_64

3. If an update is available, apply the update so that the changes take effect on the next reboot:

   # bootupctl update

   Example output

   Updated: grub2-efi-x64-1:2.04-31.fc33.x86_64,shim-x64-15-8.x86_64

Machine config method

Another way to enable bootupd is by providing a machine config.

• Provide a machine config file with the enabled systemd unit, as shown in the following example:

  Example output

    variant: rhcos
    version: 1.1.0
    systemd:
      units:
        - name: custom-bootupd-auto.service
          enabled: true
          contents: |
            [Unit]
            Description=Bootupd automatic update
            [Service]
            ExecStart=/usr/bin/bootupctl update
            RemainAfterExit=yes
            [Install]
            WantedBy=multi-user.target

Creating the cluster

To create the OKD cluster, you wait for the bootstrap process to complete on the machines that you provisioned by using the Ignition config files that you generated with the installation program.

Prerequisites

• Create the required infrastructure for the cluster.

• You obtained the installation program and generated the Ignition config files for your cluster.

• You used the Ignition config files to create FCOS machines for your cluster.

• Your machines have direct Internet access or have an HTTP or HTTPS proxy available.

Procedure

1. Monitor the bootstrap process:

   $ ./openshift-install --dir=<installation_directory> wait-for bootstrap-complete \ (1)
       --log-level=info (2)

   1	For <installation_directory>, specify the path to the directory that you stored the installation files in.
   2	To view different installation details, specify warn, debug, or error instead of info.

   Example output

   INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
   INFO API v1.20.0 up
   INFO Waiting up to 30m0s for bootstrapping to complete...
   INFO It is now safe to remove the bootstrap resources

   The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.

2. After bootstrap process is complete, remove the bootstrap machine from the load balancer.

   You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the machine itself.

Logging in to the cluster by using the CLI

You can log in to your cluster as a default system user by exporting the cluster kubeconfig file. The kubeconfig file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OKD installation.

Prerequisites

• You deployed an OKD cluster.

• You installed the oc CLI.

Procedure

1. Export the kubeadmin credentials:

   $ export KUBECONFIG=<installation_directory>/auth/kubeconfig (1)

   1	For <installation_directory>, specify the path to the directory that you stored the installation files in.

2. Verify you can run oc commands successfully using the exported configuration:

   $ oc whoami

   Example output

   system:admin

Approving the certificate signing requests for your machines

When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself. The client requests must be approved first, followed by the server requests.

Prerequisites

• You added machines to your cluster.

Procedure

1. Confirm that the cluster recognizes the machines:

   $ oc get nodes

   Example output

   NAME      STATUS    ROLES   AGE  VERSION
   master-0  Ready     master  63m  v1.20.0
   master-1  Ready     master  63m  v1.20.0
   master-2  Ready     master  64m  v1.20.0
   worker-0  NotReady  worker  76s  v1.20.0
   worker-1  NotReady  worker  70s  v1.20.0

   The output lists all of the machines that you created.

   The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

2. Review the pending CSRs and ensure that you see the client requests with the Pending or Approved status for each machine that you added to the cluster:

   $ oc get csr

   Example output

   NAME        AGE     REQUESTOR                                                                   CONDITION
   csr-8b2br   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending
   csr-8vnps   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending
   ...

   In this example, two machines are joining the cluster. You might see more approved CSRs in the list.

3. If the CSRs were not approved, after all of the pending CSRs for the machines you added are in Pending status, approve the CSRs for your cluster machines:

   Because the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. Once the client CSR is approved, the Kubelet creates a secondary CSR for the serving certificate, which requires manual approval. Then, subsequent serving certificate renewal requests are automatically approved by the machine-approver if the Kubelet requests a new certificate with identical parameters.

   For clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the oc exec, oc rsh, and oc logs commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by the node-bootstrapper service account in the system:node or system:admin groups, and confirm the identity of the node.

   • To approve them individually, run the following command for each valid CSR:

     $ oc adm certificate approve <csr_name> (1)

     1	<csr_name> is the name of a CSR from the list of current CSRs.

   • To approve all pending CSRs, run the following command:

     $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve

     Some Operators might not become available until some CSRs are approved.

4. Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:

   $ oc get csr

   Example output

   NAME        AGE     REQUESTOR                                                                   CONDITION
   csr-bfd72   5m26s   system:node:ip-10-0-50-126.us-east-2.compute.internal                       Pending
   csr-c57lv   5m26s   system:node:ip-10-0-95-157.us-east-2.compute.internal                       Pending
   ...

5. If the remaining CSRs are not approved, and are in the Pending status, approve the CSRs for your cluster machines:

   • To approve them individually, run the following command for each valid CSR:

     $ oc adm certificate approve <csr_name> (1)

     1	<csr_name> is the name of a CSR from the list of current CSRs.

   • To approve all pending CSRs, run the following command:

     $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve

6. After all client and server CSRs have been approved, the machines have the Ready status. Verify this by running the following command:

   $ oc get nodes

   Example output

   NAME      STATUS    ROLES   AGE  VERSION
   master-0  Ready     master  73m  v1.20.0
   master-1  Ready     master  73m  v1.20.0
   master-2  Ready     master  74m  v1.20.0
   worker-0  Ready     worker  11m  v1.20.0
   worker-1  Ready     worker  11m  v1.20.0

   It can take a few minutes after approval of the server CSRs for the machines to transition to the Ready status.

Additional information

• For more information on CSRs, see Certificate Signing Requests.

Initial Operator configuration

After the control plane initializes, you must immediately configure some Operators so that they all become available.

Prerequisites

• Your control plane has initialized.

Procedure

1. Watch the cluster components come online:

   $ watch -n5 oc get clusteroperators

   Example output

   NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
   authentication                             4.7.0   True        False         False      3h56m
   baremetal                                  4.7.0   True        False         False      29h
   cloud-credential                           4.7.0   True        False         False      29h
   cluster-autoscaler                         4.7.0   True        False         False      29h
   config-operator                            4.7.0   True        False         False      6h39m
   console                                    4.7.0   True        False         False      3h59m
   csi-snapshot-controller                    4.7.0   True        False         False      4h12m
   dns                                        4.7.0   True        False         False      4h15m
   etcd                                       4.7.0   True        False         False      29h
   image-registry                             4.7.0   True        False         False      3h59m
   ingress                                    4.7.0   True        False         False      4h30m
   insights                                   4.7.0   True        False         False      29h
   kube-apiserver                             4.7.0   True        False         False      29h
   kube-controller-manager                    4.7.0   True        False         False      29h
   kube-scheduler                             4.7.0   True        False         False      29h
   kube-storage-version-migrator              4.7.0   True        False         False      4h2m
   machine-api                                4.7.0   True        False         False      29h
   machine-approver                           4.7.0   True        False         False      6h34m
   machine-config                             4.7.0   True        False         False      3h56m
   marketplace                                4.7.0   True        False         False      4h2m
   monitoring                                 4.7.0   True        False         False      6h31m
   network                                    4.7.0   True        False         False      29h
   node-tuning                                4.7.0   True        False         False      4h30m
   openshift-apiserver                        4.7.0   True        False         False      3h56m
   openshift-controller-manager               4.7.0   True        False         False      4h36m
   openshift-samples                          4.7.0   True        False         False      4h30m
   operator-lifecycle-manager                 4.7.0   True        False         False      29h
   operator-lifecycle-manager-catalog         4.7.0   True        False         False      29h
   operator-lifecycle-manager-packageserver   4.7.0   True        False         False      3h59m
   service-ca                                 4.7.0   True        False         False      29h
   storage                                    4.7.0   True        False         False      4h30m

2. Configure the Operators that are not available.

Disabling the default OperatorHub sources

Operator catalogs that source content provided by Red Hat and community projects are configured for OperatorHub by default during an OKD installation. In a restricted network environment, you must disable the default catalogs as a cluster administrator.

Procedure

• Disable the sources for the default catalogs by adding disableAllDefaultSources: true to the OperatorHub object:

  $ oc patch OperatorHub cluster --type json \
      -p '[{"op": "add", "path": "/spec/disableAllDefaultSources", "value": true}]'

Image registry removed during installation

On platforms that do not provide shareable object storage, the OpenShift Image Registry Operator bootstraps itself as Removed. This allows openshift-installer to complete installations on these platform types.

After installation, you must edit the Image Registry Operator configuration to switch the managementState from Removed to Managed.

Image registry storage configuration

The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.

Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.

Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

Configuring registry storage for bare metal and other manual installations

As a cluster administrator, following installation you must configure your registry to use storage.

Prerequisites

• Cluster administrator permissions.

• A cluster that uses manually-provisioned Fedora CoreOS (FCOS) nodes, such as bare metal.

• Persistent storage provisioned for your cluster, such as Red Hat OpenShift Container Storage.

  OKD supports ReadWriteOnce access for image registry storage when you have only one replica. To deploy an image registry that supports high availability with two or more replicas, ReadWriteMany access is required.

• Must have 100Gi capacity.

Procedure

1. To configure your registry to use storage, change the spec.storage.pvc in the configs.imageregistry/cluster resource.

   When using shared storage, review your security settings to prevent outside access.

2. Verify that you do not have a registry pod:

   $ oc get pod -n openshift-image-registry

   If the storage type is emptyDIR, the replica number cannot be greater than 1.

3. Check the registry configuration:

   $ oc edit configs.imageregistry.operator.openshift.io

   Example output

   storage:
     pvc:
       claim:

   Leave the claim field blank to allow the automatic creation of an image-registry-storage PVC.

4. Check the clusteroperator status:

   $ oc get clusteroperator image-registry

5. Ensure that your registry is set to managed to enable building and pushing of images.

   • Run:

     $ oc edit configs.imageregistry/cluster

     Then, change the line

     managementState: Removed

     to

     managementState: Managed

Configuring storage for the image registry in non-production clusters

You must configure storage for the Image Registry Operator. For non-production clusters, you can set the image registry to an empty directory. If you do so, all images are lost if you restart the registry.

Procedure

• To set the image registry storage to an empty directory:

  $ oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"storage":{"emptyDir":{}}}}'

  Configure this option for only non-production clusters.

  If you run this command before the Image Registry Operator initializes its components, the oc patch command fails with the following error:

  Error from server (NotFound): configs.imageregistry.operator.openshift.io "cluster" not found

  Wait a few minutes and run the command again.

Configuring block registry storage

To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate rollout strategy.

Procedure

1. To set the image registry storage as a block storage type, patch the registry so that it uses the Recreate rollout strategy and runs with only one (1) replica:

   $ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'

2. Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.

3. Edit the registry configuration so that it references the correct PVC.

Completing installation on user-provisioned infrastructure

After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.

Prerequisites

• Your control plane has initialized.

• You have completed the initial Operator configuration.

Procedure

1. Confirm that all the cluster components are online with the following command:

   $ watch -n5 oc get clusteroperators

   Example output

   NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
   authentication                             4.7.0   True        False         False      3h56m
   baremetal                                  4.7.0   True        False         False      29h
   cloud-credential                           4.7.0   True        False         False      29h
   cluster-autoscaler                         4.7.0   True        False         False      29h
   config-operator                            4.7.0   True        False         False      6h39m
   console                                    4.7.0   True        False         False      3h59m
   csi-snapshot-controller                    4.7.0   True        False         False      4h12m
   dns                                        4.7.0   True        False         False      4h15m
   etcd                                       4.7.0   True        False         False      29h
   image-registry                             4.7.0   True        False         False      3h59m
   ingress                                    4.7.0   True        False         False      4h30m
   insights                                   4.7.0   True        False         False      29h
   kube-apiserver                             4.7.0   True        False         False      29h
   kube-controller-manager                    4.7.0   True        False         False      29h
   kube-scheduler                             4.7.0   True        False         False      29h
   kube-storage-version-migrator              4.7.0   True        False         False      4h2m
   machine-api                                4.7.0   True        False         False      29h
   machine-approver                           4.7.0   True        False         False      6h34m
   machine-config                             4.7.0   True        False         False      3h56m
   marketplace                                4.7.0   True        False         False      4h2m
   monitoring                                 4.7.0   True        False         False      6h31m
   network                                    4.7.0   True        False         False      29h
   node-tuning                                4.7.0   True        False         False      4h30m
   openshift-apiserver                        4.7.0   True        False         False      3h56m
   openshift-controller-manager               4.7.0   True        False         False      4h36m
   openshift-samples                          4.7.0   True        False         False      4h30m
   operator-lifecycle-manager                 4.7.0   True        False         False      29h
   operator-lifecycle-manager-catalog         4.7.0   True        False         False      29h
   operator-lifecycle-manager-packageserver   4.7.0   True        False         False      3h59m
   service-ca                                 4.7.0   True        False         False      29h
   storage                                    4.7.0   True        False         False      4h30m

   Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:

   $ ./openshift-install --dir=<installation_directory> wait-for install-complete (1)

   1	For <installation_directory>, specify the path to the directory that you stored the installation files in.

   Example output

   INFO Waiting up to 30m0s for the cluster to initialize...

   The command succeeds when the Cluster Version Operator finishes deploying the OKD cluster from Kubernetes API server.

   The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.

2. Confirm that the Kubernetes API server is communicating with the pods.

   1. To view a list of all pods, use the following command:

      $ oc get pods --all-namespaces

      Example output

      NAMESPACE                         NAME                                            READY   STATUS      RESTARTS   AGE
      openshift-apiserver-operator      openshift-apiserver-operator-85cb746d55-zqhs8   1/1     Running     1          9m
      openshift-apiserver               apiserver-67b9g                                 1/1     Running     0          3m
      openshift-apiserver               apiserver-ljcmx                                 1/1     Running     0          1m
      openshift-apiserver               apiserver-z25h4                                 1/1     Running     0          2m
      openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8        1/1     Running     0          5m
      ...

   2. View the logs for a pod that is listed in the output of the previous command by using the following command:

      $ oc logs <pod_name> -n <namespace> (1)

      1	Specify the pod name and namespace, as shown in the output of the previous command.

      If the pod logs display, the Kubernetes API server can communicate with the cluster machines.

3. For an installation with Fibre Channel Protocol (FCP), additional steps are required to enable multipathing. Do not enable multipathing during installation.

   See “Enabling multipathing with kernel arguments on RHCOS” in the Post-installation configuration documentation for more information.

Additional resources

• See About remote health monitoring for more information about the Telemetry service

Next steps

• Customize your cluster.

• If necessary, you can opt out of remote health reporting.

• Set up your registry and configure registry storage.