Allow installation of consul-k8s into a non-default namespace

[paulbouwer]

Issue

When installing Consul into a Kubernetes cluster via the Consul Helm Chart and targeting a namespace that is not default, there is the following issue.

The consul-k8s server-acl-init command executed by the server-acl-init-job attempts to get the Kubernetes api-server service kubernetes.default.svc.

See https://github.com/hashicorp/consul-k8s/blob/master/subcommand/server-acl-init/command.go#L347

This code attempts to obtain the service from the namespace specified to the helm chart. If this namespace value is default, then everything just works. If this namespace value is something like consul, then the code fails.

While running in a Pod, the Kubernetes apiserver is accessible via a Service named kubernetes in the default namespace. Therefore, Pods can use the kubernetes.default.svc hostname to query the API server. Official client libraries do this automatically.

https://kubernetes.io/docs/tasks/administer-cluster/access-cluster-api/#accessing-the-api-from-a-pod

Solution

Hardcode the namespace searched by this specific piece of code to default, since that is always where the service will be.

[lkysow]

Fixed by #107