Installing and configuring a microk8s edge cluster

Introduction

This content provides a summary of how to install microk8s, a lightweight and small Kubernetes cluster, on an Ubuntu Linux AMD64-based system. (For more detailed instructions, see the microk8s documentation .)

Pre-requisites

• Architecture must be x86_64
• Operating system must be an Ubuntu LTS distribution

Note: This type of single node edge cluster is meant for development and test only. A single worker node Kubernetes cluster does not provide the scalability or high availability performance characteristics that a production system should have.

Installing

1. Install microk8s:

   sudo snap install microk8s --classic --channel=stable
   

2. If you are not running as root, add your user to the microk8s group:

   sudo usermod -a -G microk8s $USER
   sudo chown -f -R $USER ~/.kube
   su - $USER   # create new session for group update to take place
   

3. Enable “dns” and “storage” modules in microk8s:

   microk8s.enable dns
   microk8s.enable storage
   

   Note: Microk8s uses 8.8.8.8 and 8.8.4.4 as upstream name servers by default. If these name servers cannot resolve the management hub hostname, you must change the name servers that microk8s is using:

   1. Retrieve the list of upstream name servers in /etc/resolv.conf or /run/systemd/resolve/resolv.conf.

   2. Edit coredns configmap in the kube-system namespace. Set the upstream nameservers in the forward section.

      microk8s.kubectl edit -n kube-system cm/coredns
      

   3. For more information about Kubernetes DNS, see the Kubernetes documentation .

4. Check the status:

   microk8s.status --wait-ready
   

5. The microK8s kubectl command is called microk8s.kubectl to prevent conflicts with an already installed kubectl command. Assuming that kubectl is not installed, add this alias for microk8s.kubectl:

   echo 'alias kubectl=microk8s.kubectl' >> ~/.bash_aliases
   source ~/.bash_aliases
   

6. Enable the container registry and configure Docker to tolerate the insecure registry:

   1. Enable the container registry:

      microk8s.enable registry
      export REGISTRY_ENDPOINT=localhost:32000
      export REGISTRY_IP_ENDPOINT=$(kubectl get service registry -n container-registry | grep registry | awk '{print $3;}'):5000
      

   2. Install docker (if not already installed):

      curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
      add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
      apt-get install docker-ce docker-ce-cli containerd.io
      

   3. Define this registry as insecure to docker. Create or add to /etc/docker/daemon.json by replacing <registry-endpoint> with the $REGISTRY_ENDPOINT environment variable value that you obtained in a previous step. Also, replace <registry-ip-endpoint> with the value of the $REGISTRY_IP_ENDPOINT environment variable value that you obtained in a previous step.

      {
        "insecure-registries": [ "<registry-endpoint>", "<registry-ip-endpoint>" ]
      }
      

   4. Restart docker to pick up the change:

      sudo systemctl restart docker
      

What’s next

• Installing the Cluster Agent

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