📌 Automate Kubernetes Cluster Using Ansible

Sangeeth Sahana D

5 min readJan 13, 2022

🔅 Launch ec2-instances on AWS Cloud eg. for master and slave.

🔅 Create roles that will configure master node and slave node seperately.

🔅 Launch a wordpress and mysql database connected to it in the respectine slaves.

🔅 Expose the wordpress pod and client able hit the wordpress ip with its respective port.

STEP1: Create a dynamic inventory

yum install python3 -y

pip3 install boto

$ mkdir -p /opt/ansible/inventory
$ cd /opt/ansible/inventory

aws_ec2.yaml:

plugin: aws_ec2
aws_access_key: <YOUR-AWS-ACCESS-KEY-HERE>
aws_secret_key: <YOUR-AWS-SECRET-KEY-HERE>
keyed_groups:
  - key: tags
    prefix: tag

’

[inventory]
enable_plugins = aws_ec2

Listing and pinging the EC2 instances:

$ ansible-inventory -i /opt/ansible/inventory/aws_ec2.yaml --list
$ ansible all -m ping

STEP2: Launch one master and two slave nodes on AWS

ansible-playbook <file_name>

aws.yml:

- hosts: localhost
  vars_files:
          secret.yml  tasks:
         - name: "Creating Master Node"
           ec2:
                 region: ap-south-1
                 aws_access_key: "{{ access_key }}"
                 aws_secret_key: "{{ secret_key }}"
                 vpc_subnet_id: {subnet}
                 count: 1
                 state: present
                 instance_type: t2.micro
                 key_name: redhat-key
                 assign_public_ip: yes
                 group_id: sg-xxxx
                 image: ami-xxxx
                 instance_tags:
                     name: master
                         - name: "Creating Slave Nodes"
           ec2:
                 region: ap-south-1
                 aws_access_key: "{{ access_key }}"
                 aws_secret_key: "{{ secret_key }}"
                 vpc_subnet_id: subnetxxx
                 count: 2
                 state: present
                 instance_type: t2.micro
                 key_name: redhat-key
                 assign_public_ip: yes
                 group_id: sg-xxxx
                 image: ami-xxx
                 instance_tags:
                      name: slave

secret.yml:

aws_access_key: <YOUR-AWS-ACCESS-KEY-HERE>
aws_secret_key: <YOUR-AWS-SECRET-KEY-HERE>

STEP3: Create yml file for MySQL and Wordpress

apiVersion: v1
kind: Secret
metadata:
  name: mysecure
data:
  rootpass: xxx
  userpass: xxx 
apiVersion: v1
kind: Service
metadata:
  name: wordpress-mysql
  labels:
    app:  wordpress
spec:
  ports:
    - port: 3306
  selector:
    app: wordpress
    tier: mysql
  clusterIP: None---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name:  wordpress-mysql
  labels:
    app:  wordpress
spec:
  selector:
    matchLabels:
      app:  wordpress
      tier: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app:  wordpress
        tier: mysql
    spec:
      containers:
      - image: mysql:5.6
        name: mysql
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysecure
              key: rootpass
        - name: MYSQL_USER
          value: vd
        - name: MYSQL_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysecure
              key: userpass
        - name: MYSQL_DATABASE
          value: sqldb
        ports:
        - containerPort: 3306
          name: mysql

‘

apiVersion: v1
kind: Service
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  ports:
    - port: 80
  selector:
    app: wordpress
    tier: mysql
  type: LoadBalancer---apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  selector:
    matchLabels:
      app:  wordpress
      tier: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: wordpress
        tier: mysql
    spec:
      containers:
      - image: wordpress:latest
        name: wordpress
        env:
        - name: WORDPRESS_DB_HOST
          value: wordpress-mysql
        - name: WORDPRESS_DB_USER
          value: vd
        - name: WORDPRESS_DB_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysecure
              key: userpass
        - name: WORDPRESS_DB_NAME
          value: sqldb
        ports:
        - containerPort: 80
          name: wordpress

Ansible-playbook — Master node

kubernetes.repo

[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-$basearch
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg

- name: Adding Kubeadm repo
   copy:
            src: kubernetes.repo
            dest: /etc/yum.repos.d
- name: Installing docker
        package:
                  name: "docker"
                  state: present      - name: Installing kubeadm
        package:
                    name: "kubeadm"
                    state: present- name: Enabling docker service
        service:
             name: docker
             state: started
             enabled: yes- name: Pulling all kubeadm config image
      command: kubeadm config images pull     
      ignore_errors: no- name: Changing driver cgroup to systemd
    copy:
           src: daemon.json
           dest: /etc/docker/daemon.json- name: Removing swapfile from /etc/fstab
    mount:
                name: "{{ item }}"
                fstype: swap
                state: absent
        with_items:
                - swap
                - none- name: Enabling kubelet service
    service:
            name: kubelet
            daemon_reload: yes
            state: started
            enabled: yes      - name: Restarting docker service
        service:
              name: docker
              state: "restarted"- name: Installing iproute-tc
    package:
           name: iproute-tc
           state: present
           update_cache: yes- name: Initializing the kubeadm
    shell: "kubeadm init --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=Swap --ignore-preflight-errors=NumCPU --ignore-preflight-errors=Mem --node-name=master"
   
    register: kubeadm
    ignore_errors: yes
   
- debug:
         msg: "{{ kubeadm }}"- name: Setup kubeconfig for home user
   shell: "{{ item }}"
   with_items:
             - "mkdir -p $HOME/.kube"
             - "cp -i /etc/kubernetes/admin.conf $HOME/.kube/config"
             - "chown $(id -u):$(id -g) $HOME/.kube/config"- name: Adding flannel network
    shell: kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml- name: Joining token
      shell: "kubeadm token create --print-join-command"
      register: token
     - debug:
              msg: "{{ token }}"
              ignore_errors: yes     - name: Storing token into a file
       local_action: copy content={{ token.stdout_lines[0] }}         dest=../slave1/token.sh- name: Copying mysql-database.yml file
   copy:
	              src: database.yaml
	              dest: /root
	       
 - name: Copying wordpress.yml file
   copy:
	               src: wordpress.yml
	               dest: /root- shell: "kubectl apply -f /root/database.yaml"
	       register: mysql	- shell: "kubectl apply -f /root/wordpress.yml"
	       register: wordpress	- debug:
	       msg: "{{ mysql }}- debug:
               msg: "{{ wordpress }}"

daemon.json:

{
        "exec-opts": ["native.cgroupdriver=systemd"]
}

Ansible-playbook for slave node

k8s.conf file:net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1

- name: Copying k8s.conf file
     copy:
            src: k8s.conf
            dest: /etc/sysctl.d/k8s.conf- name: Copying token file at /root location
   copy:
             src: token.sh
             dest: /root/token.sh  - name: Joining slave node to master node
    shell: "sh /root/token.sh"
    register: joined  - debug:
        msg: "{{ joined }}"