Merge pull request #7555 from dirathea/plugins-k8s-caData-support

Plugins k8s ca data support

docs/features/kubernetes/configuration.md

@@ -29,6 +29,7 @@ kubernetes:
           serviceAccountToken: ${K8S_MINIKUBE_TOKEN}
           dashboardUrl: http://127.0.0.1:64713 # url copied from running the command: minikube service kubernetes-dashboard -n kubernetes-dashboard
           dashboardApp: standard
+          caData: ${K8S_CONFIG_CA_DATA}
         - url: http://127.0.0.2:9999
           name: aws-cluster-1
           authProvider: 'aws'
@@ -135,6 +136,24 @@ See also
 https://github.com/backstage/backstage/tree/master/plugins/kubernetes/src/utils/clusterLinks/formatters
 for real examples.
 
+##### `clusters.\*.caData` (optional)
+
+PEM-encoded certificate authority certificates.
+
+This values could be obtained via inspecting the Kubernetes config file (usually
+at `~/.kube/config`) under `clusters.cluster.certificate-authority-data`. For
+GKE, execute the following command to obtain the value
+
+```
+gcloud container clusters describe <YOUR_CLUSTER_NAME> \
+    --zone=<YOUR_COMPUTE_ZONE> \
+    --format="value(masterAuth.clusterCaCertificate)"
+```
+
+See also
+https://cloud.google.com/kubernetes-engine/docs/how-to/api-server-authentication#environments-without-gcloud
+for complete docs about GKE without `gcloud`.
+
 #### `gke`
 
 This cluster locator is designed to work with Kubernetes clusters running in