/ansible-kubernetes-kubeadm-ha

Installation of Highly Available 'Stacked Control Plane' Kubernetes cluster using Ansible and Kubeadm

Ansible Playbooks to install an HA Kubernetes (multi-master) cluster using Kubeadm.

This repository provides Ansible Playbooks to install a Kubernetes HA cluster in an airgapped environment.

  • Uses recently GA'd Kubeadm HA joining features

Prerequisites:

  • Install Ansible and a forward proxy on the Ansible host

    • Ansible: for macos brew install ansible for linux yum install ansible

  • Setup ssh access from Ansible host to Kubernetes nodes. ssh-copy-id -i ~/.ssh/id_rsa.pub <user@host>

Environment preparation:

Specify the Master and Workers in the inventory/*cluster* file:

[k8s-masters] # these are all the masters
[k8s-workers] # these are all the worker nodes

Update the inventory/group_vars/*cluster* section:

  • choose the desired versions for kubernetes and docker
  • setup the pod network cidr (default setup is for calico - modify in calico.yaml as well)
  • specify the version of Helm to use
  • specify the Local Storage Provisioner version

Install a highly available kubernetes using kubeadm

You can now run install-all.yaml playbook to get your cluster setup. You can also run the different playbooks separately for different purposes (setting up docker, masters, kubeadm, heml ...).

ansible-playbook -i inventory/cluster1-prod playbooks/install-all.yaml --private-key=~/.ssh/id_rsa -u %username% -v

Restarting the install:

If you need to restart the process using kubeadm reset, please use the uninstall.yaml playbook that deletes the state from all vms.

Upgrade a highly available kubernetes using kubeadm

To upgrade the kubernetes control plane run:

ansible-playbook -i inventory/cluster1-prod playbooks/upgrade-all.yaml --private-key=~/.ssh/id_rsa -u username -v

What install-all.yaml includes:

  • Adding the required yum repositories
  • Installing docker
  • Installing kubeadm, kubelet and kubectl
  • Initializing the first master with etcd and kubernetes-api
  • Join replica master nodes to the primary master
  • Adding the worker nodes to the cluster
  • Installing Helm & Tiller
  • Installing Local Storage Provisioner
  • Enable Azure AD OIDC authentication

Restarting the install:

If you need to restart the process using kubeadm reset, please use the uninstall.yaml playbook that deletes the state from all vms.

To sequentially drain and patch the underlying OS hosts:

ansible-playbook -i inventory/cluster1-prod playbooks/os-patch-updates.yaml --private-key=~/.ssh/id_rsa -u username -v