Posts tagged #ansible #kubernetes

In today's world of containerized applications, Kubernetes has emerged as the de facto standard for container orchestration. Deploying and managing Kubernetes clusters manually can be complex and time-consuming. Thankfully, automation tools like Ansible provide a powerful way to automate the installation and configuration of Kubernetes clusters.

In this blog post, we'll explore how to use Ansible to automate the installation of a Kubernetes cluster. We'll walk through the steps involved in setting up Ansible, creating playbooks, and deploying Kubernetes on a set of target servers.

SETUP

Ansible Node ansible.mylabserver.com

Master Node master.mylabserver.com

Worker Nodes worker1.mylabserver.com

worker2.mylabserver.com

Prerequisite

1) Ansible must be installed on all the nodes

2) Set Password less authentication between Ansible Node to Master and Worker Nodes

Lets Create Playbook

Create ansible.cfg

root@06432e7f921c:~#mkdir k8s-install
root@06432e7f921c:~#cd k8s-install
root@06432e7f921c:~/k8s-install#cat ansible.cfg
[defaults]
inventory=./inventory
deprecation_warnings=False

Create Inventory File

root@06432e7f921c:~/k8s-install# cat inventory
[master]
master.mylabserver.com

[worker]
worker1.mylabserver.com
worker2.mylabserver.com

Verify they are accessible from Ansible Node

root@06432e7f921c:~/k8s-install# ansible -i inventory -m ping all
worker1.mylabserver.com | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}
worker2.mylabserver.com | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}
master.mylabserver.com | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}

Create main.yaml file

root@06432e7f921c:~/k8s-install# cat main.yaml
---
- hosts: [master,worker]
  gather_facts: false
  roles:
     - role: k8s-config
       tags: common

- hosts: [master]
  gather_facts: false
  roles:
   - role: master-config
     tags: master

- hosts: [worker]
  gather_facts: false
  roles:
    - role: worker-config
      tags: worker

Create Role

root@06432e7f921c:~/k8s-install# ansible-galaxy init k8s-config
root@06432e7f921c:~/k8s-install# ansible-galaxy init master-config
root@06432e7f921c:~/k8s-install# ansible-galaxy init worker-config

Create Playbook for Common Installation

root@06432e7f921c:~/k8s-install# cat roles/k8s-config/tasks/main.yml
---
- name: Disable swap
  command: swapoff -a
  ignore_errors: yes

- name: Remove swap entry from /etc/fstab
  lineinfile:
    path: /etc/fstab
    state: absent
    regexp: '^.*swap.*$'

- name: Stop firewalld service
  service:
    name: ufw
    state: stopped
    enabled: no

- name: Ensure overlay and br_netfilter are present in containerd.conf
  lineinfile:
    path: /etc/modules-load.d/containerd.conf
    line: "{{ item }}"
    create: yes
  loop:
    - overlay
    - br_netfilter

- name: Load Kernel modules
  modprobe:
     name: "{{ item }}"
  loop:
     - overlay
     - br_netfilter

- name: Ensure kernel settings are present in kubernetes.conf
  lineinfile:
    path: /etc/sysctl.d/kubernetes.conf
    line: "{{ item }}"
    create: yes
  loop:
    - "net.bridge.bridge-nf-call-ip6tables = 1"
    - "net.bridge.bridge-nf-call-iptables = 1"
    - "net.ipv4.ip_forward = 1"

- name: Apply kernel settings
  command: sysctl --system

- name: Set DEBIAN_FRONTEND environment variable
  shell:
    cmd: export DEBIAN_FRONTEND=noninteractive

- name: Add Kubernetes GPG key
  apt_key:
     url: "https://packages.cloud.google.com/apt/doc/apt-key.gpg"
     state: present

- name: Update apt repositories
  apt:
   update_cache: yes

- name: Install required packages
  apt:
     name: "{{ item }}"
     state: present
  loop:
    - apt-transport-https
    - ca-certificates
    - curl
    - gnupg
    - lsb-release

- name: Ensure /etc/apt/keyrings directory exists
  file:
    path: /etc/apt/keyrings
    state: directory
    mode: '0755'

- name: Check if Docker repository file exists
  stat:
    path: /etc/apt/sources.list.d/docker.list
  register: docker_repo_file

- name: Add Docker repository using echo
  shell:
    cmd: 'echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null'
  when: docker_repo_file.stat.exists == false

- name: Run apt update
  apt:
    update_cache: yes


- name: Install containerd.io package
  apt:
    name: containerd.io
    state: present


- name: Generate default containerd configuration
  command:
     cmd: containerd config default > /etc/containerd/config.toml

- name: Set SystemdCgroup to true in containerd configuration
  replace:
     path: /etc/containerd/config.toml
     regexp: 'SystemdCgroup\s*=\s*false'
     replace: 'SystemdCgroup = true'

- name: Restart containerd service
  service:
    name: containerd
    state: restarted

- name: Enable containerd service
  service:
     name: containerd
     enabled: yes

- name: Download Kubernetes GPG key
  shell:
    cmd: curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.29/deb/Release.key | gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg --yes

- name: Add Kubernetes repository
  copy:
     content: |
        deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.29/deb/ /
     dest: /etc/apt/sources.list.d/kubernetes.list

- name: Update apt repositories
  apt:
    update_cache: yes

- name: Install Kubernetes components
  apt:
    name: "{{ item }}"
    state: present
  loop:
      - kubeadm
      - kubelet
      - kubectl

Create Playbook to Create Cluster

root@06432e7f921c:~/k8s-install# cat roles/master-config/tasks/main.yml
---
- name: Initialize Kubernetes Cluster
  shell:
     cmd: "kubeadm init --apiserver-advertise-address=172.31.120.93 --pod-network-cidr=192.168.0.0/16 >> /root/kubeinit.log 2>/dev/null"
     creates: /root/.kube/config

- name: Deploy Calico network
  shell:
    cmd: "kubectl --kubeconfig=/etc/kubernetes/admin.conf create -f https://raw.githubusercontent.com/projectcalico/calico/v3.27.0/manifests/tigera-operator.yaml && kubectl --kubeconfig=/etc/kubernetes/admin.conf create -f https://raw.githubusercontent.com/projectcalico/calico/v3.27.0/manifests/custom-resources.yaml"
    creates: /etc/kubernetes/admin.conf

- name: Generate and save cluster join command to /joincluster.sh
  shell:
    cmd: "kubeadm token create --print-join-command > /joincluster.sh"
    creates: /joincluster.sh

Create Playbook for worker node

root@06432e7f921c:~/k8s-install# cat roles/worker-config/tasks/main.yml
---
- name: Copy joincluster script to worker nodes
  copy:
    src: /joincluster.sh
    dest: /joincluster.sh
    mode: 0755

- name: Execute joincluster.sh script
  shell:
     cmd: /joincluster.sh

Install Common packages on all the 3 nodes

root@06432e7f921c:~/k8s-install# ansible-playbook main.yaml --tags common

PLAY [master,worker] ************************************************************************************************************************************************************************

TASK [k8s-config : Disable swap] ************************************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [master.mylabserver.com]
changed: [worker2.mylabserver.com]

TASK [k8s-config : Remove swap entry from /etc/fstab] ***************************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [master.mylabserver.com]
ok: [worker2.mylabserver.com]

TASK [k8s-config : Stop firewalld service] **************************************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [master.mylabserver.com]
ok: [worker2.mylabserver.com]

TASK [k8s-config : Ensure overlay and br_netfilter are present in containerd.conf] **********************************************************************************************************
ok: [worker1.mylabserver.com] => (item=overlay)
ok: [master.mylabserver.com] => (item=overlay)
ok: [worker2.mylabserver.com] => (item=overlay)
ok: [worker1.mylabserver.com] => (item=br_netfilter)
ok: [master.mylabserver.com] => (item=br_netfilter)
ok: [worker2.mylabserver.com] => (item=br_netfilter)

TASK [k8s-config : Load Kernel modules] *****************************************************************************************************************************************************
ok: [worker1.mylabserver.com] => (item=overlay)
ok: [master.mylabserver.com] => (item=overlay)
ok: [worker2.mylabserver.com] => (item=overlay)
ok: [worker1.mylabserver.com] => (item=br_netfilter)
ok: [master.mylabserver.com] => (item=br_netfilter)
ok: [worker2.mylabserver.com] => (item=br_netfilter)

TASK [k8s-config : Ensure kernel settings are present in kubernetes.conf] *******************************************************************************************************************
ok: [worker1.mylabserver.com] => (item=net.bridge.bridge-nf-call-ip6tables = 1)
ok: [worker2.mylabserver.com] => (item=net.bridge.bridge-nf-call-ip6tables = 1)
ok: [master.mylabserver.com] => (item=net.bridge.bridge-nf-call-ip6tables = 1)
ok: [worker1.mylabserver.com] => (item=net.bridge.bridge-nf-call-iptables = 1)
ok: [worker2.mylabserver.com] => (item=net.bridge.bridge-nf-call-iptables = 1)
ok: [master.mylabserver.com] => (item=net.bridge.bridge-nf-call-iptables = 1)
ok: [worker1.mylabserver.com] => (item=net.ipv4.ip_forward = 1)
ok: [worker2.mylabserver.com] => (item=net.ipv4.ip_forward = 1)
ok: [master.mylabserver.com] => (item=net.ipv4.ip_forward = 1)

TASK [k8s-config : Apply kernel settings] ***************************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [master.mylabserver.com]
changed: [worker2.mylabserver.com]

TASK [k8s-config : Set DEBIAN_FRONTEND environment variable] ********************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [master.mylabserver.com]
changed: [worker2.mylabserver.com]

TASK [k8s-config : Add Kubernetes GPG key] **************************************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [master.mylabserver.com]
ok: [worker2.mylabserver.com]

TASK [k8s-config : Update apt repositories] *************************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [master.mylabserver.com]
changed: [worker2.mylabserver.com]

TASK [k8s-config : Install required packages] ***********************************************************************************************************************************************
ok: [worker1.mylabserver.com] => (item=apt-transport-https)
ok: [master.mylabserver.com] => (item=apt-transport-https)
ok: [worker2.mylabserver.com] => (item=apt-transport-https)
ok: [worker1.mylabserver.com] => (item=ca-certificates)
ok: [master.mylabserver.com] => (item=ca-certificates)
ok: [worker2.mylabserver.com] => (item=ca-certificates)
ok: [worker1.mylabserver.com] => (item=curl)
ok: [master.mylabserver.com] => (item=curl)
ok: [worker1.mylabserver.com] => (item=gnupg)
ok: [worker2.mylabserver.com] => (item=curl)
ok: [master.mylabserver.com] => (item=gnupg)
ok: [worker1.mylabserver.com] => (item=lsb-release)
ok: [worker2.mylabserver.com] => (item=gnupg)
ok: [master.mylabserver.com] => (item=lsb-release)
ok: [worker2.mylabserver.com] => (item=lsb-release)

TASK [k8s-config : Ensure /etc/apt/keyrings directory exists] *******************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [worker2.mylabserver.com]
ok: [master.mylabserver.com]

TASK [k8s-config : Check if Docker repository file exists] **********************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [master.mylabserver.com]
ok: [worker2.mylabserver.com]

TASK [k8s-config : Add Docker repository using echo] ****************************************************************************************************************************************
skipping: [master.mylabserver.com]
skipping: [worker2.mylabserver.com]
skipping: [worker1.mylabserver.com]

TASK [k8s-config : Run apt update] **********************************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [worker2.mylabserver.com]
changed: [master.mylabserver.com]

TASK [k8s-config : Install containerd.io package] *******************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [worker2.mylabserver.com]
changed: [master.mylabserver.com]

TASK [k8s-config : Generate default containerd configuration] *******************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [master.mylabserver.com]
changed: [worker2.mylabserver.com]

TASK [k8s-config : Set SystemdCgroup to true in containerd configuration] *******************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [worker2.mylabserver.com]
ok: [master.mylabserver.com]

TASK [k8s-config : Restart containerd service] **********************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [master.mylabserver.com]
changed: [worker2.mylabserver.com]

TASK [k8s-config : Enable containerd service] ***********************************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [master.mylabserver.com]
ok: [worker2.mylabserver.com]

TASK [k8s-config : Download Kubernetes GPG key] *********************************************************************************************************************************************
[WARNING]: Consider using the get_url or uri module rather than running 'curl'.  If you need to use command because get_url or uri is insufficient you can add 'warn: false' to this command
task or set 'command_warnings=False' in ansible.cfg to get rid of this message.
changed: [master.mylabserver.com]
changed: [worker2.mylabserver.com]
changed: [worker1.mylabserver.com]

TASK [k8s-config : Add Kubernetes repository] ***********************************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [master.mylabserver.com]
ok: [worker2.mylabserver.com]

TASK [k8s-config : Update apt repositories] *************************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [worker2.mylabserver.com]
changed: [master.mylabserver.com]

TASK [k8s-config : Install Kubernetes components] *******************************************************************************************************************************************
ok: [worker1.mylabserver.com] => (item=kubeadm)
ok: [master.mylabserver.com] => (item=kubeadm)
ok: [worker2.mylabserver.com] => (item=kubeadm)
ok: [worker1.mylabserver.com] => (item=kubelet)
ok: [master.mylabserver.com] => (item=kubelet)
ok: [worker2.mylabserver.com] => (item=kubelet)
ok: [worker1.mylabserver.com] => (item=kubectl)
ok: [worker2.mylabserver.com] => (item=kubectl)
ok: [master.mylabserver.com] => (item=kubectl)

Install Cluster On Master Node

root@06432e7f921c:~/k8s-install# ansible-playbook main.yaml --tags master
PLAY [master] *******************************************************************************************************************************************************************************

TASK [master-config : Initialize Kubernetes Cluster] ****************************************************************************************************************************************
changed: [master.mylabserver.com]

TASK [master-config : Deploy Calico network] ************************************************************************************************************************************************
changed: [master.mylabserver.com]

TASK [master-config : Generate and save cluster join command to /joincluster.sh] ************************************************************************************************************
changed: [master.mylabserver.com]

PLAY RECAP **********************************************************************************************************************************************************************************
master.mylabserver.com     : ok=26   changed=12   unreachable=0    failed=0    skipped=1    rescued=0    ignored=0

Install Cluster On Worker Node

root@06432e7f921c:~/k8s-install# ansible-playbook main.yaml --tags worker

PLAY [worker] *******************************************************************************************************************************************************************************

TASK [worker-config : Copy joincluster script to worker nodes] ******************************************************************************************************************************
ok: [worker1.mylabserver.com]
ok: [worker2.mylabserver.com]

TASK [worker-config : Execute joincluster.sh script] ****************************************************************************************************************************************
changed: [worker1.mylabserver.com]
changed: [worker2.mylabserver.com]

PLAY RECAP **********************************************************************************************************************************************************************************
worker1.mylabserver.com    : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
worker2.mylabserver.com    : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Create a .kube file and copy admin to .kube dir

root@06432e7f921c:~/k8s-install# mkdir /root/.kube
root@06432e7f921c:~/k8s-install# cp /etc/kubernetes/admin.conf /root/.kube/config

Lets Verify Cluster Configured properly

root@06432e7f921c:~/k8s-install# kubectl get nodes
NAME                      STATUS   ROLES           AGE   VERSION
master.mylabserver.com    Ready    control-plane   54m   v1.29.3
worker1.mylabserver.com   Ready    <none>          43m   v1.29.3
worker2.mylabserver.com   Ready    <none>          43m   v1.29.3

Conclusion Automating the installation of Kubernetes using Ansible can significantly simplify the process and reduce the chance of errors. With Ansible playbooks, we can quickly provision and configure Kubernetes clusters on any infrastructure, whether it's on-premises or in the cloud.

In this blog post, we've only scratched the surface of what's possible with Ansible. As you become more familiar with Ansible and Kubernetes, you can further customize your playbooks to meet your specific requirements and integrate additional automation tasks.

Happy automating!

CloudOpsKube

Tag: #ansible #kubernetes

Automating Kubernetes Installation with Ansible