Port Requirements

To operate properly, Rancher requires a number of ports to be open on Rancher nodes and on downstream Kubernetes cluster nodes.

• Rancher Nodes
  • Ports for Rancher Server Nodes on K3s
  • Ports for Rancher Server Nodes on RKE
  • Ports for Rancher Server Nodes on RKE2
  • Ports for Rancher Server in Docker
• Downstream Kubernetes Cluster Nodes
  • Ports for Rancher Launched Kubernetes Clusters using Node Pools
  • Ports for Rancher Launched Kubernetes Clusters using Custom Nodes
  • Ports for Hosted Kubernetes Clusters
  • Ports for Registered Clusters
• Other Port Considerations
  • Commonly Used Ports
  • Local Node Traffic
  • Rancher AWS EC2 Security Group
  • Opening SUSE Linux Ports

Rancher Nodes

The following table lists the ports that need to be open to and from nodes that are running the Rancher server.

The port requirements differ based on the Rancher server architecture.

Rancher can be installed on any Kubernetes cluster. For Rancher installs on a K3s, RKE, or RKE2 Kubernetes cluster, refer to the tabs below. For other Kubernetes distributions, refer to the distribution’s documentation for the port requirements for cluster nodes.

Notes:

• Rancher nodes may also require additional outbound access for any external authentication provider which is configured (LDAP for example).
• Kubernetes recommends TCP 30000-32767 for node port services.
• For firewalls, traffic may need to be enabled within the cluster and pod CIDR.
• Rancher nodes may also need outbound access to an external S3 location which is used for storing cluster backups (Minio for example).

Ports for Rancher Server Nodes on K3s

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The K3s server needs port 6443 to be accessible by the nodes.

The nodes need to be able to reach other nodes over UDP port 8472 when Flannel VXLAN is used. The node should not listen on any other port. K3s uses reverse tunneling such that the nodes make outbound connections to the server and all kubelet traffic runs through that tunnel. However, if you do not use Flannel and provide your own custom CNI, then port 8472 is not needed by K3s.

If you wish to utilize the metrics server, you will need to open port 10250 on each node.

Important: The VXLAN port on nodes should not be exposed to the world as it opens up your cluster network to be accessed by anyone. Run your nodes behind a firewall/security group that disables access to port 8472.

The following tables break down the port requirements for inbound and outbound traffic:

Inbound Rules for Rancher Server Nodes

Outbound Rules for Rancher Nodes

Ports for Rancher Server Nodes on RKE

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Typically Rancher is installed on three RKE nodes that all have the etcd, control plane and worker roles.

The following tables break down the port requirements for traffic between the Rancher nodes:

Rules for traffic between Rancher nodes

The following tables break down the port requirements for inbound and outbound traffic:

Inbound Rules for Rancher Nodes

Outbound Rules for Rancher Nodes

Ports for Rancher Server Nodes on RKE2

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The RKE2 server needs port 6443 and 9345 to be accessible by other nodes in the cluster.

All nodes need to be able to reach other nodes over UDP port 8472 when Flannel VXLAN is used.

If you wish to utilize the metrics server, you will need to open port 10250 on each node.

Important: The VXLAN port on nodes should not be exposed to the world as it opens up your cluster network to be accessed by anyone. Run your nodes behind a firewall/security group that disables access to port 8472.

Inbound Rules for RKE2 Server Nodes

Typically all outbound traffic is allowed.

Ports for Rancher Server in Docker

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The following tables break down the port requirements for Rancher nodes, for inbound and outbound traffic:

Inbound Rules for Rancher Node

Outbound Rules for Rancher Node

Downstream Kubernetes Cluster Nodes

Downstream Kubernetes clusters run your apps and services. This section describes what ports need to be opened on the nodes in downstream clusters so that Rancher can communicate with them.

The port requirements differ depending on how the downstream cluster was launched. Each of the tabs below list the ports that need to be opened for different cluster types.

The following diagram depicts the ports that are opened for each cluster type.

Port Requirements for the Rancher Management Plane

Tip:

If security isn’t a large concern and you’re okay with opening a few additional ports, you can use the table in Commonly Used Ports as your port reference instead of the comprehensive tables below.

Ports for Rancher Launched Kubernetes Clusters using Node Pools

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The following table depicts the port requirements for Rancher Launched Kubernetes with nodes created in an Infrastructure Provider.

Note: The required ports are automatically opened by Rancher during creation of clusters in cloud providers like Amazon EC2 or DigitalOcean.

Ports for Rancher Launched Kubernetes Clusters using Custom Nodes

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The following table depicts the port requirements for Rancher Launched Kubernetes with Custom Nodes.

Ports for Hosted Kubernetes Clusters

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The following table depicts the port requirements for hosted clusters.

Ports for Registered Clusters

Note: Registered clusters were called imported clusters before Rancher v2.5.

Click to expand

The following table depicts the port requirements for registered clusters.

Other Port Considerations

Commonly Used Ports

These ports are typically opened on your Kubernetes nodes, regardless of what type of cluster it is.

Local Node Traffic

Ports marked as local traffic (i.e., 9099 TCP) in the above requirements are used for Kubernetes healthchecks (livenessProbe andreadinessProbe). These healthchecks are executed on the node itself. In most cloud environments, this local traffic is allowed by default.

However, this traffic may be blocked when:

• You have applied strict host firewall policies on the node.
• You are using nodes that have multiple interfaces (multihomed).

In these cases, you have to explicitly allow this traffic in your host firewall, or in case of public/private cloud hosted machines (i.e. AWS or OpenStack), in your security group configuration. Keep in mind that when using a security group as source or destination in your security group, explicitly opening ports only applies to the private interface of the nodes / instances.

Rancher AWS EC2 Security Group

When using the AWS EC2 node driver to provision cluster nodes in Rancher, you can choose to let Rancher create a security group called rancher-nodes. The following rules are automatically added to this security group.

Opening SUSE Linux Ports

SUSE Linux may have a firewall that blocks all ports by default. To open the ports needed for adding the host to a custom cluster,

1. SSH into the instance.

2. Start YaST in text mode:

   sudo yast2

3. Navigate to Security and Users > Firewall > Zones:public > Ports. To navigate within the interface, follow the instructions here.

4. To open the required ports, enter them into the TCP Ports and UDP Ports fields. In this example, ports 9796 and 10250 are also opened for monitoring. The resulting fields should look similar to the following:

   TCP Ports
   22, 80, 443, 2376, 2379, 2380, 6443, 9099, 9796, 10250, 10254, 30000-32767
   UDP Ports
   8472, 30000-32767

5. When all required ports are enter, select Accept.

6. SSH into the instance.

7. Edit /etc/sysconfig/SuSEfirewall2 and open the required ports. In this example, ports 9796 and 10250 are also opened for monitoring: FW_SERVICES_EXT_TCP="22 80 443 2376 2379 2380 6443 9099 9796 10250 10254 30000:32767" FW_SERVICES_EXT_UDP="8472 30000:32767" FW_ROUTE=yes
8. Restart the firewall with the new ports: SuSEfirewall2

Result: The node has the open ports required to be added to a custom cluster.