DevOps Garfield

Reference: k0sctl installation

1. Required prep - Ensure unique system ID. K0s cluster deployment will fail if aren't.

   sudo systemd-machine-id-setup

2. System prep ( RPM-based distros )
   1. Download the binary:
      1. URL: https://github.com/k0sproject/k0sctl/releases

1. Login as root as required by the commands we're using

   sudo su -

2. Create the directory

   mkdir -p /etc/k0s

3. Copy or generate the configuration file
   1. If you already have a configuration file, copy it into the current directory
   2. If you don't already have a k0sctl.yaml ( configuration ) file, create a default configuration file

      k0s config create > /etc/k0s/k0sctl.yaml

      1. The conent will look like the following:

         apiVersion: k0sctl.k0sproject.io/v1beta1
         kind: Cluster
         metadata:
           name: k0s-cluster
           user: admin
         spec:
           hosts:
           - ssh:
               address: 10.0.0.1  # Update this entry to specify hostname or IP address
               user: root
               port: 22
               keyPath: null      # Update this entry to specify the key path
             role: controller
           - ssh:
               address: 10.0.0.2  # Update this entry to specify hostname or IP address
               user: root
               port: 22
               keyPath: null      # Update this entry to specify the key path
             role: worker
           options:
             wait:
               enabled: true
             drain:
               enabled: true
               gracePeriod: 2m0s
               timeout: 5m0s
               force: true
               ignoreDaemonSets: true
               deleteEmptyDirData: true
               podSelector: ""
               skipWaitForDeleteTimeout: 0s
             concurrency:
               limit: 30
               uploads: 5
             evictTaint:
               enabled: false
               taint: k0sctl.k0sproject.io/evict=true
               effect: NoExecute
               controllerWorkers: false

4. Create the cluster

   k0sctl apply --config /etc/k0s/k0sctl.yaml

5. If you want to use kubectl, lens, or other tools outside the cluster nodes, then you will need a “kubeconfig” file. You can generate the file with the following command

   k0s kubeconfig > ~/.kubeconfig

6. Don't forget to set the proper permission. This file contains credentials ( certs ) that allow access without entering any information

   chmod 600 ~/.kubeconfig

7. Find the ports that need to be open

   grep -i port /etc/k0s/k0s.yaml

8. Open the required firewall ports:

   firewall-cmd --permanent --add-port={8133/tcp,2379/tcp,2380/tcp,10257/tcp,10259/tcp,9443/tcp,8132/tcp,6443/tcp,10249/tcp}
   firewall-cmd --reload

1. Watch the cluster deployment as they start ( to quit, press CTRL+C )

   watch -n1 'k0s kubectl get all -A; echo; k0s kubectl get node'

Note that you should always have an odd number of controll nodes. Therefore, you should have 1 or 3 or 5 control nodes, depending on the cluster size. For a non-production environment, start wtih 1. For production environments, start with 3. Monitor the kube-apiserver performance. If it starts to show hi CPU utilization, increase the number of CPUs on the controll node(s).

1. On the existing controller node
   1. Create the controller node token

      k0s token create --role=controller --expiry=1h > token-file

   2. Transfer the new token file to each worker node

      scp token-file user@<new-controller>:~/

   3. Transfer the k0s.yaml config file to the new controller node(s)

      scp k0s.yaml user@<new-controller>:~/

1. Check the status of the cluster

   k0s status
   
   Version: v1.32.4+k0s.0
   Process ID: 109946
   Role: controller
   Workloads: false
   SingleNode: false

1. Check the status of the cluster

   k0s status
   
   Version: v1.32.4+k0s.0
   Process ID: 91481
   Role: worker
   Workloads: true
   SingleNode: false
   Kube-api probing successful: true
   Kube-api probing last error:  

1. Run the following command:

   kubectl get nodes

It should look something like this

[garfield@k8s01 ~]$ kubectl get nodes
NAME                       STATUS   ROLES           AGE   VERSION
k8s01.home.mygarfield.us   Ready    control-plane   17h   v1.31.1
k8s02.home.mygarfield.us   Ready    <none>          10m   v1.31.1
k8s03.home.mygarfield.us   Ready    <none>          6s    v1.31.1