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Calico Open Source 3.29 (latest) documentation

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:

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​

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'

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

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"}}}'

Additional resources​