kubernetes

Ansible role for docker & kubernetes on a Debian host

available tags

• install

  Will install docker and kubernetes. Do this to bootstrap all nodes.

• init_kubernetes_master

  Will initialize a kubernetes master. Only use when initially setting up a cluster.

• generate_kubernetes_join_command

  Run against master. Will copy a join command to local machine. Use join_kubernetes_cluster afterwards to join nodes to your kubernetes cluster.

• join_kubernetes_cluster

  Will use join command created by generate_kubernetes_join_command to join an existing kubernetes cluster.

• init_single_node_cluster

  May be used after init_kubernetes_master to create a single node cluster.

available variables

• kubernetes_version

  Install specific version of kubernetes. Show available versions: curl -s https://packages.cloud.google.com/apt/dists/kubernetes-xenial/main/binary-amd64/Packages | grep Version | awk '{print $2}'

• control_plane_endpoint

  The kuberenetes api endpoint. This address is used by all nodes to communicate with the api. In a high availability cluster this is normaly set to a load balancer, which distribute incoming requests across all master nodes. In newer versions of kubernetes this may also be a DNS name. For a single node test cluster a possible value could be localhost for example.

examples

Instead of using the playbook like shown below, you can also adapt the playbook. Check Ansible documentation.

installing docker and kubernetes

Either install a single node

ansible-playbook playbook.yml -i <your-servers-dns-or-ip>, --tag install

or a bunch of nodes.

ansible-playbook playbook.yml -i <your-servers-dns-or-ip>,<your-servers-dns-or-ip>,<your-servers-dns-or-ip> --tag install

setting up a master node

Instead of using the masters ip for kubernetes api queries, you should think about using a load balancer like suggested in the kubernetes documentation. This is especially relevent for multi-master clusters. Single node-clusters for development don't need this.

ansible-playbook playbook.yml -i <your-servers-dns-or-ip>, --tag init_kubernetes_master --extra-vars "control_plane_endpoint=<your-loadbalancer-or-dns>"

The control plane could also be a DNS name.

setting up a single-node cluster for testing purposes

ansible-playbook playbook.yml -i <your-servers-dns-or-ip>, --tag install,init_kubernetes_master,init_single_node_cluster, --extra-vars "control_plane_endpoint=localhost"