Using an external VCL ConfigMap

Introduction

Sometimes it’s necessary to manage VCL outside of the Varnish deployment lifecycle. For example, when your VCL is managed by separate teams or when Varnish Enterprise is used for multi-tenancy. In such cases, Varnish Enterprise Helm Chart can be configured to use an external ConfigMap as its source for VCL.

Do note that changes made to external ConfigMap are not automatically updated in a Pod by Kubernetes. It is necessary to run a kubectl rollout after a ConfigMap is updated for the changes to take effect:

$ kubectl rollout restart statefulset/varnish-enterprise  # for StatefulSet
$ kubectl rollout restart deployment/varnish-enterprise   # for Deployment
$ kubectl rollout restart daemonset/varnish-enterprise    # for DaemonSet

Configuring an external ConfigMap

To use an external ConfigMap, first create a ConfigMap with the desired VCL in the same namespace as Varnish Enterprise. For example, save the following content to configmap.yaml and apply it with kubectl apply -f configmap.yaml:

apiVersion: v1
kind: ConfigMap
metadata:
  name: varnish-vcl
  namespace: varnish
data:
  default.vcl: |
    vcl 4.1;

    backend default {
      .host = "www.example.com";
      .port = "80";
    }

    sub vcl_backend_fetch {
      set bereq.http.Host = "www.example.com";
    }

Once ConfigMap is added, configure server.vclConfig, server.extraVolumes, and server.extraVolumeMounts:

server:
  vclConfig: ""  # This value must be set to an empty string

  extraVolumes:
    - name: varnish-vcl
      configMap:
        name: varnish-vcl

  extraVolumeMounts:
    - name: varnish-vcl
      mountPath: /etc/varnish/default.vcl
      subPath: default.vcl  # Set this to the key name of the file in a ConfigMap

The server.extraVolumeMounts[].mountPath must match that of server.vclConfigPath.