Integrating COS Lite with Charmed Kubernetes

Charmed Kubernetes includes the standard Kubernetes dashboard for monitoring your cluster. However, it is often advisable to have a monitoring solution which will run whether the cluster itself is running or not. It may also be useful to integrate monitoring into existing setups.

To make monitoring your cluster a delightful experience, Canonical provides first-class integration between Charmed Kubernetes and COS Lite (Canonical Observability Stack). This guide will help you integrate a COS Lite deployment with a Charmed Kubernetes deployment.

This document assumes you have a controller with an installation of Charmed Kubernetes. If this is not your case, refer to "Installing Charmed Kubernetes".

Preparing a platform for COS Lite

First, create a Microk8s model to act as a deployment cloud for COS Lite:

juju add-model --config logging-config='<root>=DEBUG' microk8s-ubuntu aws

We also set the logging level to DEBUG so that helpful debug information is shown when you use juju debug-log (see juju debug-log).

Note: If you are unfamiliar with Juju models, the documentation can be found here.

Use the Ubuntu charm to deploy an application named “microk8s”:

juju deploy ubuntu microk8s --series=focal --constraints="mem=8G cores=4 root-disk=30G"

Deploy Microk8s on Ubuntu by accessing the unit you created at the last step with juju ssh microk8s/0 and following the Install Microk8s guide for configuration.

Export the Microk8s kubeconfig file to your current directory after configuration:

juju ssh microk8s/0 -- microk8s config > microk8s-config.yaml

Register Microk8s as a Juju cloud using add-k8s (see "juju add-k8s" for details on the add-k8s command):

KUBECONFIG=microk8s-config.yaml juju add-k8s microk8s

Deploying COS Lite on the Microk8s cloud

On the Microk8s cloud, create a new model and deploy the cos-lite charm:

juju add-model cos-lite microk8s
juju deploy cos-lite

Make cos-lite’s endpoints available for cross-model integration:

juju offer grafana:grafana-dashboard
juju offer prometheus:receive-remote-write

Use juju status --relations to verify that both grafana and prometheus offerings are listed.

At this point, you’ve established a Microk8s model on Ubuntu and incorporated it into Juju as a Kubernetes cloud. You then used this cloud as a substrate for the COS Lite deployment. You therefore have 2 models on the same controller.

Integrating COS Lite with Charmed Kubernetes

Switch to your charmed-kubernetes model (if you forgot the name of your model, you can run juju models to see a list of available models):

juju switch <charmed-kubernetes-model>

Consume the COS Lite endpoints:

juju consume cos-lite.grafana
juju consume cos-lite.prometheus

Deploy the grafana-agent:

Juju deploy grafana-agent

Relate grafana-agent to k8s, kubernetes-control-plane and kubernetes-worker:

juju integrate grafana-agent:cos-agent k8s:cos-agent
juju integrate grafana-agent:cos-agent kubernetes-control-plane:cos-agent
juju integrate grafana-agent:cos-agent kubernetes-worker:cos-agent

Relate grafana-agent to the COS Lite offered interfaces:

juju integrate grafana-agent grafana
juju integrate grafana-agent prometheus

Get the credentials and login URL for Grafana:

juju run grafana/0 get-admin-password -m cos-lite

The above command will output:

admin-password: b9OhxF5ndUDO
url: http://10.246.154.87/cos-lite-grafana

The username for this credential is admin.

You’ve successfully gained access to a comprehensive observability stack. Visit the URL and use the credentials to log in.

Once you feel ready to dive deeper into your shiny new observability platform, you can head over to the COS Lite documentation.