deepak2102/test

K8s Cluster Upgrade [Ansible]

Description

The objective of this ansible-playbook is to upgrade the kubernetes cluster from 1.18 to 1.23. The playbook has 5 roles with some pre-tasks and post-tasks.

Roles:

• Update Source Repository
  • This role creates local source repo for docker/containerd, kubernetes and its dependencies installation.
  • Then it checks for any missing packages in the local-repository.
  • If any of the package is missing in the local apt repository, the playbook is interrupted generating a file containing missing package name.
• Update image registry
  • This role is optional.
  • If set to TRUE, this role will install docker on management_server(db_server in case of OCD/LRF-RDF and tag & push the docker image to local-registry
  • If set to FALSE, the execution of all the tasks in this role will be skipped.
• Upgrade Container Runtime
  • This role upgrades the existing container runtime, either docker or containerd (depends on selecyion in variable file)
  • This role can also migrate container runtime from docker to containerd if migrate_to_containerd is set to true.
• Upgrade Kubeadm Cluster
  • This role upgrades the kubeadm cluster from current version 1.18 to 1.23
  • This role also sense the current version of the cluster and applies the upgrade from current to 1.23
• Upgrade Cluster Components
  • This role upgardes the cluster component metallb if upgrade_metallb is set to true
  • This role upgardes the cluster component calico if upgrade_calico is set to true

Inventory

The inventory will differ for each cluster. The inventory file is located in the inventory/<cluster_name> directory with the name "hosts".

Example:
	For OCD-PTH01, the inventory file is located at inventory/ocdph01/hosts

For OCD in PTH01 the inventory hosts file contains following entries for servers.

[kubernetes:children]
kube_worker
kube_master

[kube_worker]
OCDPH01-W01
OCDPH01-W02

[kube_master]
OCDPH01-M01

[db_server]
OCDPH01-DB01

[local_repository]
OCDPH01-DB01

[local_image_registry]
OCDPH01-DB01

** Please note that the nomenclature of the above should not be changed with actual hostname.
** The correct IP address should be present in /etc/hosts file for each server.

Variables

There are 3 main location of variable files

1. group_vars/all/ ----> mainly, for those parameters whose values are likely to be same accross all environment

2. inventory/<cluster>/group_vars/all/ ---> mainly, for those parameters whose values are likely to be different for each environment.
   inventory/<cluster>/host_vars/<inventory_hostname> ---> host specific variables and likely to be different for each environment.
   
3. roles/vars/main.yaml ---> This variable files contains parameters for developers.
	

variables@group_vars/all/main.yml

logs_dir: /tmp
# The directory where ansible playbook error logs are stored.

images_dir: /tmp/kubernetes-upgrade
# This directory under the /tmp contains all docker images to be uploaded on local docker registry

tag_and_push_images: yes
# All container images are pulled from the local registry during upgrades. Push images to local registry if not already done. Select [yes/no]

migrate_to_containerd: no
# Docker is not supported as container-runtime in K8s version 1.24 and later. Migrate from Docker to containerd container-runtime. Select [yes/no]

container_runtime: docker
# Select the container runtime to upgrade

upgrade_container_runtime: yes
# Existing container runtime is upgraded is the value is set to YES


upgrade_calico: yes
# Existing cni calico is upgraded is the value is set to YES

upgrade_metallb: yes
# Existing load balancer metallb is upgraded is the value is set to YES

variables@group_vars/all/version.yml

ansible_python_interpreter: /usr/bin/python3
# instructs playbook to use python3 interpreter.

kubeadm_upgrade_sequence:
# Kubeadm cluster can be upgraded to the next minor version only. Please enter the sequence of upgrade.

upgrade_calico_version:
# Enter the calico version to upgrade

upgrade_metallb_version: 0.12.1
# Enter the metallb version to upgrade

kubernetes_images:
# Enter the list of all docker images for K8s upgrade to be pushed to local registry. Use the correct format only. Refer to the variable file.

calico_cni_images:
# Enter the list of all docker images for calico upgrade to be pushed to local registry. Use the correct format only. Refer to the variable file.

metallb_images:
# Enter the list of all docker images for metallb upgrade to be pushed to local registry. Use the correct format only. Refer to the variable file.

Vault

The vault contains passwords to be used during task execution by ansible.

To edit the file:
	ansible-vault edit vault/secrets.yml
	Password: <provide vault password here to edit the file>

Execute the playbook

~~~
ansible-playbook upgrade-k8s-cluster.yml -i inventory/<cluster_name> -e "@vault/secrets.yml" --ask-vault-pass
password: <provide the vault password here>

Example:
ansible-playbook upgrade-k8s-cluster.yml -i inventory/gdaph01 -e "@vault/secrets.yml" --ask-vault-pass
~~~