support mounting custom secrets in the kiali pod

[jmazzitelli]

part of: kiali/kiali#4468

[jmazzitelli]

Here's how you can test assuming you have istio installed in istio-system namespace:

helm install -n istio-system kiali-server _output/charts/kiali-server-*-SNAPSHOT.tgz \
   --set deployment.custom_secrets[0].name=mazz \
   --set deployment.custom_secrets[0].mount=/mazzpath \
   --set deployment.custom_secrets[0].optional=true \
   --set deployment.custom_secrets[1].name=foo \
   --set deployment.custom_secrets[1].mount=/foopath \
   --set deployment.custom_secrets[1].optional=true

Now see that the Kiali pod has the correct yaml (I did not create the secrets, but with optional=true it doesn't matter that the secrets do not actually exist - just knowing the pod started successfully and has the correct yaml is good):

See the volumeMounts exist:

$ for s in mazz foo; do kubectl get pods -n istio-system -l app=kiali -o jsonpath="{.items[0].spec.containers[0].volumeMounts[?(@.name==\"${s}\")]}" | jq; done
{
  "mountPath": "/mazzpath",
  "name": "mazz"
}
{
  "mountPath": "/foopath",
  "name": "foo"
}

See the volumes exist:

$ for s in mazz foo; do kubectl get pods -n istio-system -l app=kiali -o jsonpath="{.items[0].spec.volumes[?(@.name==\"${s}\")]}" | jq; done
{
  "name": "mazz",
  "secret": {
    "defaultMode": 420,
    "optional": true,
    "secretName": "mazz"
  }
}
{
  "name": "foo",
  "secret": {
    "defaultMode": 420,
    "optional": true,
    "secretName": "foo"
  }
}

[jmazzitelli]

testing looks good: kiali/kiali#4468 (comment)

[jshaughn]

LOK

[jmazzitelli]

assigning to @mattmahoneyrh so he can determine if the community testing and molecule testing is good enough.