Three Node K3s Using Install Script

I was looking for an alternative to k3sup method to install a k3s cluster.( Refer this link on how to setup k3s using k3sup.)

Most of the content below is based from the quick start guide here - https://docs.k3s.io/quick-start

Generate a token that will be used to join additional nodes to the kubernetes cluster":

openssl rand -hex 10 > k3s_secret.txt

Install the first control plane node: curl -sfL https://get.k3s.io | K3S_TOKEN=cat k3s_secret.txt sh -s - server --cluster-init

k3sadmin@k3s-control1:~$ curl -sfL https://get.k3s.io | K3S_TOKEN=`cat k3s_secret.txt` sh -s - server --cluster-init                    
[INFO]  Finding release for channel stable
[INFO]  Using v1.28.6+k3s2 as release
[INFO]  Downloading hash https://github.com/k3s-io/k3s/releases/download/v1.28.6+k3s2/sha256sum-amd64.txt
[INFO]  Downloading binary https://github.com/k3s-io/k3s/releases/download/v1.28.6+k3s2/k3s
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
[INFO]  Skipping installation of SELinux RPM
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Creating /usr/local/bin/ctr symlink to k3s
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service.
[INFO]  systemd: Starting k3s

Validate if the node is up: sudo kubectl get nodes

k3sadmin@k3s-control1:~$ sudo kubectl get nodes
NAME           STATUS   ROLES                       AGE   VERSION
k3s-control1   Ready    control-plane,etcd,master   14m   v1.28.6+k3s2

Copy the token to the other nodes:

scp -v k3s_secret.txt k3sadmin@k3s-control2:/home/k3sadmin
scp -v k3s_secret.txt k3sadmin@k3s-control3:/home/k3sadmin

Install and join the second node: curl -sfL https://get.k3s.io | K3S_TOKEN=cat k3s_secret.txt sh -s - server --server https://k3s-control1:6443

k3sadmin@k3s-control2:~$ curl -sfL https://get.k3s.io | K3S_TOKEN=`cat k3s_secret.txt` sh -s - server --server https://k3s-control1:6443
[INFO]  Finding release for channel stable
[INFO]  Using v1.28.6+k3s2 as release
[INFO]  Downloading hash https://github.com/k3s-io/k3s/releases/download/v1.28.6+k3s2/sha256sum-amd64.txt
[INFO]  Downloading binary https://github.com/k3s-io/k3s/releases/download/v1.28.6+k3s2/k3s
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
[INFO]  Skipping installation of SELinux RPM
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Creating /usr/local/bin/ctr symlink to k3s
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service.
[INFO]  systemd: Starting k3s

Install and join the third control plane node: curl -sfL https://get.k3s.io | K3S_TOKEN=cat k3s_secret.txt sh -s - server --server https://k3s-control1:6443

k3sadmin@k3s-control3:~$ curl -sfL https://get.k3s.io | K3S_TOKEN=`cat k3s_secret.txt` sh -s - server --server https://k3s-control1:6443
[INFO]  Finding release for channel stable
[INFO]  Using v1.28.6+k3s2 as release
[INFO]  Downloading hash https://github.com/k3s-io/k3s/releases/download/v1.28.6+k3s2/sha256sum-amd64.txt
[INFO]  Downloading binary https://github.com/k3s-io/k3s/releases/download/v1.28.6+k3s2/k3s
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
[INFO]  Skipping installation of SELinux RPM
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Creating /usr/local/bin/ctr symlink to k3s
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service.
[INFO]  systemd: Starting k3s

Validate

k3sadmin@k3s-control1:~$ sudo kubectl get nodes
NAME           STATUS   ROLES                       AGE     VERSION
k3s-control1   Ready    control-plane,etcd,master   22m     v1.28.6+k3s2
k3s-control2   Ready    control-plane,etcd,master   4m29s   v1.28.6+k3s2
k3s-control3   Ready    control-plane,etcd,master   72s     v1.28.6+k3s2

k3sadmin@k3s-control1:~$ sudo kubectl get svc -A
NAMESPACE     NAME             TYPE           CLUSTER-IP     EXTERNAL-IP                           PORT(S)                      AGE
default       kubernetes       ClusterIP      10.43.0.1      <none>                                443/TCP                      23m
kube-system   kube-dns         ClusterIP      10.43.0.10     <none>                                53/UDP,53/TCP,9153/TCP       23m
kube-system   metrics-server   ClusterIP      10.43.61.109   <none>                                443/TCP                      23m
kube-system   traefik          LoadBalancer   10.43.75.94    172.16.1.11,172.16.1.12,172.16.1.13   80:32470/TCP,443:32299/TCP   22m

Cluster Access:

The kubeconfig file is stored at /etc/rancher/k3s/k3s.yaml

Copy the /etc/rancher/k3s/k3s.yaml file from the control node to the jumpbox host under - /home/username/.kube/config

Set the KUBECONFIG environmental variable: export KUBECONFIG=/home/username/.kube/config