Kubernetes Cluster Ansible

Are you setting up your first Kubernetes cluster on CentOS 7 and want to borrow ideas to create your own perfect ansible script? Then this repository is for you!

Here we have a small collection of not-perfect ansible scripts to setup a k8s master and k8s nodes.

Assumptions

These scripts make a few assumptions:

• Ansible is installed on some machine not in the cluster

• There are 3+ nodes for the cluster using near-virgin install of CentOS 7 using static IP addresses

  • One CentOS 7 install for the kubernetes master

  • One or more CentOS 7 install for the kubernetes nodes

• You’re expected to read and understand these scripts

• You’re expected to change the scripts to suit your needs

• You’re expected to read the doc pages for all kubernetes commands used in the playbooks (hah, just kidding)

Provision the Kubernetes Cluster

First copy k8s-cluster.template as k8s-cluster and modify it to house the hosts used in the cluster.

Important

The ansible scripts create user centos with password kubernetes for use in the cluster. Change the password using mkpasswd --method=sha-512 and updating the ansible scripts.

Next use ansible to provision the cluster. It is split out into three steps for clarity.

export ANSIBLE_HOST_KEY_CHECKING=false
ansible-playbook -i k8s-cluster step-1-install-dependencies.yaml
ansible-playbook -i k8s-cluster step-2-cluster-init.yaml
ansible-playbook -i k8s-cluster step-3-nodes-join-cluster.yaml

Next setup tooling to get insight into what is going on with the cluster:

• WeaveWorks: kubectl apply -f "https://cloud.weave.works/k8s/scope.yaml?k8s-service-type=NodePort&k8s-version=$(kubectl version | base64 | tr -d '\n')"

  • Fantastic tool to see cpu, memory, hosts, images, pods, controllers/services, processes, everything about the cluster status.

• TODO try some others, especially one-stop logging for debugging