Reconfiguring the K8S API endpoint in Juju

Overview

A known limitation of MicroStack today is that the Juju Controller (the service responsible for orchestrating the deployment of MicroStack) only communicates with a single Kubernetes API address.

MicroK8S does not setup load balancing in front of the Kubernetes API. This means that if the node the Juju Controller is communicating with is removed, Juju will not be able to communicate with the Kubernetes cluster anymore.

There are plans to setup load balancing and a highly available IP address to provide more robust access to the Kubernetes API service from Juju in the future.

If you need the Juju controller to communicate to an alternative kube-api server you can update the endpoint in the Juju controller to point to a different kube-api server.

In the following example the deployment name is sbcloud01 - controller and cloud names are built from this name.

Pre-requisites

Ensure that the Juju client is logged in to the Juju controller:

$ sunbeam utils juju-login
Juju re-login complete.

Create a new cloud configuration

Create a new cloud configuration file sbcloud01-k8s.yaml with the new endpoint address:

clouds:
  sbcloud01-k8s:
    type: kubernetes
    auth-types: [oauth2, clientcertificate]
    endpoint: https://10.4.2.3:16443 # <- new endpoint

Update the controller cloud configuration

$ juju update-cloud --controller sbcloud01-controller sbcloud01-k8s -f sbcloud01-k8s.yaml
Cloud "sbcloud01-k8s" updated on controller "sbcloud01-controller" using provided file.

If an incorrect Kubernetes API endpoint is configured error messages will be present in the openstack model debug log:

$ juju debug-log -m openstack