Schedule Typha for scaling to well-known nodes

Big picture

Schedule Typha to well-known nodes.

Value

By scheduling Typha to well-known nodes, you can reduce the number of nodes which expose Typha’s listen port.

Concepts

Typha

Typha is a Calico component which improves scalability and reduces the impact that large clusters may have on the Kubernetes API. Typha agents must accept connections from other agents on a fixed port.

As part of the Calico bootstrap infrastructure, Typha must be available before pod networking begins and uses host networking instead. It opens a port on the node it is scheduled on. By default, it can get scheduled to any node and opens TCP 5473.

How to

Tell if you have installed Typha

• Operator
• Manifest

Operator based installations always include Typha.

Check if the calico-typha deployment exists in the kube-system namespace.

kubectl get deployment -n kube-system calico-typha

Schedule Typha to well-known nodes

• Operator
• Manifest

You can use the Installation API to configure a node affinity for Typha pods. The operator supports both preferredDuringSchedulingIgnoredDuringExecution and requiredDuringSchedulingIgnoredDuringExecution options.

For example, to require the scheduler to place Typha on nodes with the label “typha=allowed”:

kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
  name: default
spec:
  typhaAffinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - matchExpressions:
        - key: typha
          operator: In
          values:
          - allowed

See scheduling Typha to well-known nodes.