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Configuring the Calico Kubernetes controllers

The Calico Kubernetes controllers are primarily configured through environment variables. When running the controllers as a Kubernetes pod, this is accomplished through the pod manifest env section.

The calico/kube-controllers container

The calico/kube-controllers container includes the following controllers:

  1. policy controller: watches network policies and programs Calico policies.
  2. profile controller: watches namespaces and programs Calico profiles.
  3. workloadendpoint controller: watches for changes to pod labels and updates Calico workload endpoints.
  4. node controller: watches for the removal of Kubernetes nodes and removes corresponding data from Calico.

By default, the following controllers are enabled: profile, policy, workloadendpoint

Configuring etcd access

The Calico Kubernetes controllers support the following environment variables to configure etcd access:

Environment Description Schema
ETCD_ENDPOINTS Comma-delimited list of etcd endpoints to connect to. Example: http://10.0.0.1:2379,http://10.0.0.2:2379.  
ETCD_CA_CERT_FILE Path to the file containing the root certificate of the CA that issued the etcd server certificate. Configures the Kubernetes controllers to trust the signature on the certificates provided by the etcd server. To disable authentication of the server by the Kubernetes controllers, set the value to none. path
ETCD_CERT_FILE Path to the file containing the client certificate issued to the Kubernetes controllers. Enables the Kubernetes controllers to participate in mutual TLS authentication and identify themselves to the etcd server. Example: /etc/kube-controllers/cert.pem path
ETCD_KEY_FILE Path to the file containing the private key of the Kubernetes controllers’ client certificate. Enables the Kubernetes controllers to participate in mutual TLS authentication and identify themselves to the etcd server. Example: /etc/kube-controllers/key.pem path

The *_FILE variables are paths to the corresponding certificates/keys. As such, when the controllers are running as a Kubernetes pod, you must ensure that the files exist within the pod. This is usually done in one of two ways:

  • Mount the certificates from the host. This requires that the certificates be present on the host running the controller.
  • Use Kubernetes Secrets to mount the certificates into the pod as files.

Configuring Kubernetes API access

The controllers must have read access to the Kubernetes API in order to monitor NetworkPolicy, Pod, and Namespace events.

When running the controllers as a self-hosted Kubernetes Pod, Kubernetes API access is configured automatically and no additional configuration is required. However, the controllers can also be configured to use an explicit kubeconfig file override to configure API access if needed.

Other configuration

The following environment variables can be used to configure the Calico Kubernetes controllers.

Environment Description Schema
ENABLED_CONTROLLERS Which controllers to run policy, profile, workloadendpoint, node
LOG_LEVEL Minimum log level to be displayed. debug, info, warning, error
KUBECONFIG Path to a kubeconfig file for Kubernetes API access path

About each controller

Node controller

The node controller automatically cleans up configuration for nodes that no longer exist.

The node controller is not enabled by default. However, the Calico Kubernetes manifests do enable this controller.

To enable the node controller, perform the following two steps.

  1. Add “node” to the list of enabled controllers in the environment for kube-controllers. For example: ENABLED_CONTROLLERS=workloadendpoint,profile,policy,node
  2. Configure calico/node with a Kubernetes node reference by adding the following snippet to the environment section of the calico-node daemon set.
    - name: CALICO_K8S_NODE_REF
      valueFrom:
     fieldRef:
       fieldPath: spec.nodeName
    

Policy controller

The policy controller syncs Kubernetes network policies to the Calico data store.

The policy controller is enabled by default.

Workload endpoint controller

The workload endpoint controller automatically syncs Kubernetes pod label changes to the Calico data store by updating the corresponding workload endpoints appropriately.

The workload endpoint controller is enabled by default.

Profile controller

The profile controller syncs Kubernetes namespace label changes to the Calico data store.

The profile controller is enabled by default.