Environment Setup

This is part of the Charmed MongoDB 5 K8s Tutorial. Please refer to this page for more information and the overview of the content.

Minimum requirements

Before we start, make sure your machine meets the following requirements:

• Ubuntu 20.04 (focal) or later.
• at least 8GB of RAM.
• at least 2 CPU cores.
• At least 20GB of available storage. For production deployment: at least 60GB of available storage on each host.
• Access to the internet for downloading the required snaps and charms.

Install and prepare MicroK8s

The fastest, simplest way to get started with Charmed MongoDB K8s is to set up a local Kubernetes using MicroK8s.
MicroK8s provides lightweight zero-ops, pure-upstream Kubernetes; Charmed MongoDB K8s will be run in Kubernetes pods and managed by Juju.
While this tutorial covers the basics of MicroK8s, you can explore more MicroK8 here.

1. Install MicroK8s

Because we will use juju 3.x which is a strictly confined snap, we also need to install strict microk8s

sudo snap install microk8s --channel=1.27-strict

2. Add a user to microk8s group

sudo usermod -a -G snap_microk8s $(whoami)

3. Create ~/.kube folder and set permissions

mkdir ~/.kube
sudo chown -R $(whoami) ~/.kube

4. Reload user groups

Reload the user groups either via a reboot or by running

newgrp snap_microk8s

5. Check Kubernetes status

microk8s status --wait-ready

6. Enable required plugins

sudo microk8s enable dns storage ingress

7. (Optional) create an alias for microk8s.kubectl

sudo snap alias microk8s.kubectl kubectl

Install and prepare Juju

Juju is an Operator Lifecycle Manager (OLM) for clouds, bare metal, LXD or Kubernetes. We will be using it to deploy and manage Charmed MongoDB.
As with Microk8s, Juju is installed from a snap package:

sudo snap install juju --classic

Juju already has a built-in knowledge of Kubernetes and how it works, so there is no additional setup or configuration needed. A controller will be used to deploy and control Charmed MongoDB K8s.

1. Create a folder mkdir -p $HOME/.local/share/juju

Because Juju 3.x is a a strictly confined snap, and is not allowed to create ~/.local/share we need to create it manually.

mkdir -p $HOME/.local/share/juju

2. Bootstrap juju controller

All we need to do now is run the following command to bootstrap a Juju controller named ‘overlord’ to Kubernetes.

This bootstrapping processes can take several minutes depending on how provisioned (RAM, CPU, etc.) your machine is:

juju bootstrap microk8s overlord  --agent-version 3.1.6

The Juju controller should exist within a Kubernetes namespace. You can verify this by:

1. Typing the command

microk8s.kubectl get namespaces

and you should see the following:

microk8s.kubectl get namespaces
NAME                  STATUS   AGE
kube-system           Active   <age>
kube-public           Active   <age>
kube-node-lease       Active   <age>
default               Active   <age>
ingress               Active   <age>
controller-overlord   Active   <age>

2. Typing command

microk8s.kubectl get pods --namespace=controller-overlord

NAME                             READY   STATUS    RESTARTS      AGE
controller-0                     2/2     Running   1 (<restarted> ago)   <age>
modeloperator-6c58d95cfb-ktts7   1/1     Running   0             <age>

where <age> shows information on how long ago a namespace was created and <restarted> shows information when the pod was restarted.

The controller can work with different models; models host applications such as Charmed MongoDB K8s. Set up a specific model for Charmed MongoDB K8s named ‘tutorial’:

juju add-model tutorial

You can now view the model you created above by entering the command juju status into the command line. You should see the following:

Model     Controller  Cloud/Region        Version  SLA          Timestamp
tutorial  overlord    microk8s/localhost  3.1.6   unsupported  11:35:46Z

Model "admin/tutorial" is empty.

Next Steps

Charmed MongoDB 5 K8s Tutorial - Deploy MongoDB on K8s