Kubernetes. k0s – Cluster productivo en NAS QNAP

root@k0s-node-1:~# cat /etc/ssh/sshd_config | grep -i ^permit
PermitRootLogin yes

Recargar sshd
root@k0s-node-1:~# systemctl reload sshd

Copiar la llave pública al controlador y los workers. Por ejemplo;
jvalera@MacBook-Pro-de-Juanjo k0sctl % ssh-copy-id root@192.168.2.72
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/Users/jvalera/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.2.72's password:

Number of key(s) added: 1

Now try logging into the machine, with: "ssh 'root@192.168.2.72'"
and check to make sure that only the key(s) you wanted were added.

jvalera@MacBook-Pro-de-Juanjo k0sctl %

Deshacer el cambio de sssd para no permitir el acceso interactivo.
root@k0s-node-1:~# cat /etc/ssh/sshd_config | grep -i ^permit
PermitRootLogin prohibit-password

Recargar sshd
root@k0s-node-1:~# systemctl reload sshd

Instalar k0sctl https://github.com/k0sproject/k0sctl#installation

Crear el .yml con la configuración de k0sctl

jvalera@MacBook-Pro-de-Juanjo k0sctl % k0sctl init > k0sctl.yaml

Editar el fichero k0sctl.yaml para cambiar las IPs del Controller y de los Workers

Una vez editado el archivo se aplica con el binario k0sctl.

jvalera@MacBook-Pro-de-Juanjo k0sctl % k0sctl apply --config k0sctl.yaml

k0sctl v0.12.6 Copyright 2021, k0sctl authors. Anonymized telemetry of usage will be sent to the authors. By continuing to use k0sctl you agree to these terms: https://k0sproject.io/licenses/eula
INFO ==> Running phase: Connect to hosts
INFO [ssh] 192.168.2.73:22: connected
INFO [ssh] 192.168.2.71:22: connected
INFO [ssh] 192.168.2.72:22: connected
INFO ==> Running phase: Detect host operating systems
INFO [ssh] 192.168.2.71:22: is running Debian GNU/Linux 11 (bullseye)
INFO [ssh] 192.168.2.73:22: is running Debian GNU/Linux 11 (bullseye)
INFO [ssh] 192.168.2.72:22: is running Debian GNU/Linux 11 (bullseye)
INFO ==> Running phase: Prepare hosts
INFO [ssh] 192.168.2.73:22: installing packages (iptables)
INFO [ssh] 192.168.2.72:22: installing packages (iptables)
INFO ==> Running phase: Gather host facts
INFO [ssh] 192.168.2.73:22: using k0s-node-2 as hostname
INFO [ssh] 192.168.2.72:22: using k0s-node-1 as hostname
INFO [ssh] 192.168.2.71:22: using k0s-master as hostname
INFO [ssh] 192.168.2.73:22: discovered ens3 as private interface
INFO [ssh] 192.168.2.72:22: discovered ens3 as private interface
INFO [ssh] 192.168.2.71:22: discovered ens3 as private interface
INFO ==> Running phase: Validate hosts
INFO ==> Running phase: Gather k0s facts
INFO ==> Running phase: Validate facts
INFO ==> Running phase: Download k0s on hosts
INFO [ssh] 192.168.2.73:22: downloading k0s 1.23.3+k0s.1
INFO [ssh] 192.168.2.71:22: downloading k0s 1.23.3+k0s.1
INFO [ssh] 192.168.2.72:22: downloading k0s 1.23.3+k0s.1
INFO ==> Running phase: Configure k0s WARN [ssh] 192.168.2.71:22: generating default configuration
INFO [ssh] 192.168.2.71:22: validating configuration
INFO [ssh] 192.168.2.71:22: configuration was changed
INFO ==> Running phase: Initialize the k0s cluster
INFO [ssh] 192.168.2.71:22: installing k0s controller
INFO [ssh] 192.168.2.71:22: waiting for the k0s service to start
INFO [ssh] 192.168.2.71:22: waiting for kubernetes api to respond
INFO ==> Running phase: Install workers
INFO [ssh] 192.168.2.73:22: validating api connection to https://192.168.2.71:6443
INFO [ssh] 192.168.2.72:22: validating api connection to https://192.168.2.71:6443
INFO [ssh] 192.168.2.71:22: generating token
INFO [ssh] 192.168.2.72:22: writing join token
INFO [ssh] 192.168.2.73:22: writing join token
INFO [ssh] 192.168.2.73:22: installing k0s worker
INFO [ssh] 192.168.2.72:22: installing k0s worker
INFO [ssh] 192.168.2.73:22: starting service
INFO [ssh] 192.168.2.73:22: waiting for node to become ready
INFO [ssh] 192.168.2.72:22: starting service
INFO [ssh] 192.168.2.72:22: waiting for node to become ready
INFO ==> Running phase: Disconnect from hosts
INFO ==> Finished in 5m16s
INFO k0s cluster version 1.23.3+k0s.1 is now installed
INFO Tip: To access the cluster you can now fetch the admin kubeconfig using:
INFO k0sctl kubeconfig

Ya disponemos de un cluster de kubernetes listo para recibir lo que sea que pueda albergar. Vamos a comprobar si están levantados los servicios en el Controller y en los Workers.

jvalera@MacBook-Pro-de-Juanjo k0sctl % for i in {1..3} do ssh root@192.168.2.7$i 'systemctl is-active k0s*' done

active active active

Ahora falta conectarse con el cliente kubectl. Utilizo la propia máquina de bootstrap, generando un fichero de configuración con k0sctl.

jvalera@MacBook-Pro-de-Juanjo k0sctl % k0sctl kubeconfig --config k0sctl.yaml > k0s.cfg
jvalera@MacBook-Pro-de-Juanjo k0sctl % kubectl get nodes --kubeconfig k0s.cfg
NAME STATUS ROLES AGE VERSION k0s-node-1 Ready 95m v1.23.3+k0s k0s-node-2 Ready 95m v1.23.3+k0s