This post is for me to learn how to create a highly available Kubernetes cluster using the MicroK8s and multipass.
Kubernetes clusters host containerised applications in a reliable and scalable way. Having DevOps in mind, Kubernetes makes maintenance tasks such as upgrades and security patching simple.
MicroK8s is a zero-ops, CNCF certified lightweight Kubernetes distribution for workstations, clusters, edge and IoT devices.
Again, the prerequisite is there must be a working copy multipass, and I'm using WSL. 😎
Here are the setup configuration:
$ multipass launch --name kmaster -m 4G
$ multipass shell kmaster
ubuntu@kmaster:~$ sudo snap install microk8s --classic
ubuntu@kmaster:~$ sudo usermod -a -G microk8s ubuntu
ubuntu@kmaster:~$ sudo chown -f -R ubuntu ~/.kube
ubuntu@kmaster:~$ exit
$ multipass shell kmaster
ubuntu@kmaster:~$ microk8s status --wait-ready
Next, let setup a second node:
$ multipass launch --name kworker1 -m 4G
$ multipass shell kworker1
ubuntu@kworker1:~$ sudo snap install microk8s --classic
ubuntu@kworker1:~$ sudo usermod -a -G microk8s ubuntu
ubuntu@kworker1:~$ sudo chown -f -R ubuntu ~/.kube
ubuntu@kworker1:~$ exit
$ multipass shell kworker1
ubuntu@kworker1:~$ microk8s status --wait-ready
Both nodes are ready, let's join them:
$ multipass exec kmaster -- microk8s add-node
From the node you wish to join to this cluster, run the following:
microk8s join 172.22.71.179:25000/daaad28e6febfbdaa5e228479e5f3f7c/8ee2423760f2
Use the '--worker' flag to join a node as a worker not running the control plane, eg:
microk8s join 172.22.71.179:25000/daaad28e6febfbdaa5e228479e5f3f7c/8ee2423760f2 --worker
If the node you are adding is not reachable through the default interface you can use one of the following:
microk8s join 172.22.71.179:25000/daaad28e6febfbdaa5e228479e5f3f7c/8ee2423760f2
Copy the line (in bold) and paste to the second node (kworker), and wait for a few minutes.
ubuntu@kworker1:~$ microk8s join 172.22.71.179:25000/daaad28e6febfbdaa5e228479e5f3f7c/8ee2423760f2
Contacting cluster at 172.22.71.179
Waiting for this node to finish joining the cluster. .. .. ..
ubuntu@kworker1:~$ microk8s kubectl get nodes
NAME STATUS ROLES AGE VERSION
kmaster Ready <none> 20m v1.25.2
kworker1 Ready <none> 2m32s v1.25.2
Last, let deploy some sample containerized application and test from host browser.
ubuntu@kworker1:~$ microk8s kubectl create deployment microbot --image=dontrebootme/microbot:v1
ubuntu@kworker1:~$ microk8s kubectl scale deployment microbot --replicas=3
ubuntu@kworker1:~$ microk8s kubectl expose deployment microbot --type=NodePort --port=80 --name=microbot-service
ubuntu@kworker1:~$ microk8s kubectl get all --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system pod/calico-kube-controllers-75cc47cdf8-wnqx4 1/1 Running 0 31m
kube-system pod/metrics-server-6b6844c455-cgxpg 1/1 Running 0 26m
kube-system pod/kubernetes-dashboard-74b66d7f9c-5f7g8 1/1 Running 0 24m
kube-system pod/dashboard-metrics-scraper-64bcc67c9c-5ghrz 1/1 Running 0 24m
kube-system pod/calico-node-8k5bf 1/1 Running 0 14m
kube-system pod/calico-node-p78ws 1/1 Running 0 13m
default pod/microbot-5df46485d4-xc6m5 1/1 Running 0 34s
default pod/microbot-5df46485d4-hchk2 1/1 Running 0 25s
default pod/microbot-5df46485d4-52mhq 1/1 Running 0 25s
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default service/kubernetes ClusterIP 10.152.183.1 <none> 443/TCP 31m
kube-system service/metrics-server ClusterIP 10.152.183.24 <none> 443/TCP 26m
kube-system service/kubernetes-dashboard ClusterIP 10.152.183.143 <none> 443/TCP 25m
kube-system service/dashboard-metrics-scraper ClusterIP 10.152.183.48 <none> 8000/TCP 25m
default service/microbot-service NodePort 10.152.183.180 <none> 80:31396/TCP 10s
NAMESPACE NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
kube-system daemonset.apps/calico-node 2 2 2 2 2 kubernetes.io/os=linux 31m
NAMESPACE NAME READY UP-TO-DATE AVAILABLE AGE
kube-system deployment.apps/calico-kube-controllers 1/1 1 1 31m
kube-system deployment.apps/metrics-server 1/1 1 1 26m
kube-system deployment.apps/kubernetes-dashboard 1/1 1 1 25m
kube-system deployment.apps/dashboard-metrics-scraper 1/1 1 1 25m
default deployment.apps/microbot 3/3 3 3 35s
NAMESPACE NAME DESIRED CURRENT READY AGE
kube-system replicaset.apps/calico-kube-controllers-54c85446d4 0 0 0 31m
kube-system replicaset.apps/calico-kube-controllers-75cc47cdf8 1 1 1 31m
kube-system replicaset.apps/metrics-server-6b6844c455 1 1 1 26m
kube-system replicaset.apps/kubernetes-dashboard-74b66d7f9c 1 1 1 24m
kube-system replicaset.apps/dashboard-metrics-scraper-64bcc67c9c 1 1 1 24m
default replicaset.apps/microbot-5df46485d4 3 3 3 34s
From the output, we can see the port is exposed at port 31396. So just point the browser (at host) to http://kmaster.mshome.net:31396/
 |
| http://kmaster.mshome.net:31396/ |
Links: