Configure IP autodetection
Big picture
Configure IP autodetection for Calico nodes to ensure the correct IP address is used for routing.
Value
When you install Calico on a node, an IP address and subnet is automatically detected. Calico provides several ways to configure IP/subnet autodetection, and supports configuring specific IPs for:
- Hosts with multiple external interfaces
- Host interfaces with multiple IP addresses
- Changes to cross subnet packet encapsulation
- Changes to host IP address
Features
This how-to guide uses the following Calico features:
- Node resource
Concepts
Autodetecting node IP address and subnet
For internode routing, each Calico node must be configured with an IPv4 address and/or an IPv6 address. When you install Calico on a node, a node resource is automatically created using routing information that is detected from the host. For some deployments, you may want to update autodetection to ensure nodes get the correct IP address.
Sample default node resource after installation
apiVersion: projectcalico.org/v3
kind: Node
metadata:
name: node-hostname
spec:
bgp:
asNumber: 64512
ipv4Address: 10.244.0.1/24
ipv6Address: 2000:db8:85a3::8a2e:370:7335/120
ipv4IPIPTunnelAddr: 192.168.0.1
Autodetection methods
By default, Calico uses the first-found method; the first valid IP address on the first interface (excluding local interfaces such as the docker bridge). However, you can change the default method to any of the following:
- Address assigned to Kubernetes node (kubernetes-internal-ip)
- Address used by the node to reach a particular IP or domain (can-reach)
- Regex to include matching interfaces (interface)
- Regex to exclude matching interfaces (skip-interface)
- A list of IP ranges in CIDR format to determine valid IP addresses on the node to choose from (cidrs)
For more details on autodetection methods, see node configuration reference.
How to
Change the autodetection method
- Operator
- Manifest
As noted previously, the default autodetection method is first valid interface found (first-found). To use a different autodetection method, edit the default Installation custom resource, specifying the method. Below are examples of the supported autodetection methods:
note
To configure the default autodetection method for IPv6 for any of the below methods, use the field nodeAddressAutodetectionV6
.
Kubernetes Node IP
Calico will select the first internal IP address listed in the Kubernetes node’s
Status.Addresses
field.kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
name: default
spec:
calicoNetwork:
nodeAddressAutodetectionV4:
kubernetes: NodeInternalIP
Source address used to reach an IP or domain name
Calico will choose the IP address that is used to reach the given “can reach” IP address or domain. For example:
kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
name: default
spec:
calicoNetwork:
nodeAddressAutodetectionV4:
canReach: 8.8.8.8
Including matching interfaces
Calico will choose an address on each node from an interface that matches the given regex. For example:
kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
name: default
spec:
calicoNetwork:
nodeAddressAutodetectionV4:
interface: eth.*
Excluding matching interfaces
Calico will choose an address on each node from an interface that does not match the given regex. For example:
kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
name: default
spec:
calicoNetwork:
nodeAddressAutodetectionV4:
skipInterface: eth.*
Including CIDRs
Calico will select any IP address from the node that falls within the given CIDRs. For example:
kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
name: default
spec:
calicoNetwork:
nodeAddressAutodetectionV4:
cidrs:
- '192.168.200.0/24'
As noted previously, the default autodetection method is first valid interface found (first-found). To use a different autodetection method, use the following kubectl set env
command, specifying the method:
IPv4
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=<autodetection-method>
IPv6
kubectl set env daemonset/calico-node -n kube-system IP6_AUTODETECTION_METHOD=<autodetection-method>
Where autodetection methods are based on:
Kubernetes Node IP
Calico will select the first internal IP address listed in the Kubernetes node’s
Status.Addresses
field.kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=kubernetes-internal-ip
Source address used to reach an IP or domain name
Calico will choose the IP address that is used to reach the given “can reach” IP address or domain. For example:
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=can-reach=www.google.com
Including matching interfaces
Calico will choose an address on each node from an interface that matches the given regex. For example:
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=interface=eth.*
Excluding matching interfaces
Calico will choose an address on each node from an interface that does not match the given regex. For example:
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=skip-interface=eth.*
Including CIDRs
Calico will select any IP address from the node that falls within the given CIDRs. For example:
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=cidr=192.168.200.0/24,172.15.0.0/24
Manually configure IP address and subnet for a node
In the following scenarios, you may want to configure a specific IP and subnet:
- Hosts with multiple external interfaces
- Host interfaces with multiple IP addresses
- Changes to cross subnet packet encapsulation
Changes to host IP address
Operator
- Manifest
You can configure specific IP address and subnet for a node by disabling IP autodetection and then updating the Node resource.
Disable autodetection
To disable autodetection method, update the proper NodeAddressAutodetection
field in the Installation resource:
apiVersion: operator.tigera.io/v1
kind: Installation
metadata:
name: default
spec:
calicoNetwork:
nodeAddressAutodetectionV4: {}
nodeAddressAutodetectionV6: {}
Configure IP and subnet using node resource
You can configure the IP address and subnet on a Node resource.
Use calicoctl patch
to update the current node configuration. For example:
calicoctl patch node kind-control-plane \
--patch='{"spec":{"bgp": {"ipv4Address": "10.0.2.10/24", "ipv6Address": "fd80:24e2:f998:72d6::/120"}}}'
You can configure specific IP address and subnet for a node using environment variables or by updating the Node resource. Because you can configure IP address and subnet using either environment variables or node resource, the following table describes how values are synchronized.
If this environment variable… | Is… | Then… |
---|---|---|
IP/IP6 | Explicitly set | The specified values are used, and the Node resource is updated. |
Set to autodetect | The requested method is used (first-found, can-reach, interface, skip-interface, kubernetes-internal-ip), and the Node resource is updated. | |
Not set, but Node resource has IP/IP6 values | Node resource value is used. | |
IP | Not set, and there is no IP value in Node resource | Autodetects an IPv4 address and subnet, and updates Node resource. |
IP6 | Not set, and there is a no IP6 value in Node resource | No IP6 routing is performed on the node. |
Configure IP and subnet using environment variables
To configure IP and subnet values using environment variables, use a kubectl set env
command. For example:
kubectl set env daemonset/calico-node -n kube-system IP=10.0.2.10/24 IP6=fd80:24e2:f998:72d6::/120
note
If the subnet is omitted, the defaults are: /32 (IPv4) and /128 (IPv6). We recommend that you include the subnet information for clarity when specifying IP addresses.
Configure IP and subnet using node resource
You can also configure the IP address and subnet on a Node resource.
note
When configuring the IP address on a Node resource, you may want to disable IP address options or environment variables on the node. IP options on the container take precedence, and will overwrite the values you configure on the node resource.
Use calicoctl patch
to update the current node configuration. For example:
calicoctl patch node kind-control-plane \
--patch='{"spec":{"bgp": {"ipv4Address": "10.0.2.10/24", "ipv6Address": "fd80:24e2:f998:72d6::/120"}}}'
Additional resources
- For details on autodetection methods, see the node configuration reference.
- For calicoctl environment variables, see Configuring calico/node
- Node resource
- Reference documentation for calicoctl patch