Crear primer cluster de kubernetes (k3s)

Cluster Hello World

Vamos a crear nuestro cluster utilizando k3d todo ejecutándose en contenedores

vagrant@ubuntu1804:~$ k3d cluster create helloworld --agents 1 --servers 1

INFO[0000] Created network 'k3d-helloworld'
INFO[0000] Created volume 'k3d-helloworld-images'
INFO[0001] Creating node 'k3d-helloworld-server-0'
INFO[0001] Creating node 'k3d-helloworld-agent-0'
INFO[0002] Creating node 'k3d-helloworld-agent-1'
INFO[0004] Creating LoadBalancer 'k3d-helloworld-serverlb'
INFO[0009] Cluster 'helloworld' created successfully!
INFO[0010] You can now use it like this:
kubectl cluster-info

En nuestro ejemplo:

• –agents = # nodes
• –servers = # masters

Validando el Cluster

vagrant@ubuntu1804:~$ kubectl cluster-info

Kubernetes master is running at https://0.0.0.0:33187
CoreDNS is running at https://0.0.0.0:33187/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
Metrics-server is running at https://0.0.0.0:33187/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

Podemos listar los nodos que son parte de nuestro cluster

vagrant@ubuntu1804:~$ kubectl get nodes
NAME                      STATUS   ROLES    AGE    VERSION
k3d-helloworld-server-0   Ready    master   107s   v1.18.6+k3s1
k3d-helloworld-agent-0    Ready    <none>   107s   v1.18.6+k3s1

Podemos listar los pods que ya están en ejecución en nuestro cluster

vagrant@ubuntu1804:~$ kubectl get pods --all-namespaces

NAMESPACE     NAME                                     READY   STATUS      RESTARTS   AGE
kube-system   metrics-server-7566d596c8-rsb84          1/1     Running     0          3m2s
kube-system   local-path-provisioner-6d59f47c7-gcbbn   1/1     Running     0          3m2s
kube-system   coredns-8655855d6-bssm6                  1/1     Running     0          3m2s
kube-system   helm-install-traefik-f6f95               0/1     Completed   0          3m2s
kube-system   svclb-traefik-x55fl                      2/2     Running     0          98s
kube-system   svclb-traefik-mcl8q                      2/2     Running     0          98s
kube-system   traefik-758cd5fc85-z2c8k                 1/1     Running     0          98s

vagrant@ubuntu1804:~$ k3d cluster stop helloworld
vagrant@ubuntu1804:~$ k3d cluster start helloworld
vagrant@ubuntu1804:~$ k3d cluster delete helloworld