Launching Kubernetes Cluster using Ansible on AWS

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What is Kubernetes ?

Kubernetes is a portable, extensible, open-source platform for managing containerized workloads and services, that facilitates both declarative configuration and automation. It has a large, rapidly growing ecosystem. Kubernetes services, support, and tools are widely available.

Why you need Kubernetes and what it can do ?

Containers are a good way to bundle and run your applications. In a production environment, you need to manage the containers that run the applications and ensure that there is no downtime. For example, if a container goes down, another container needs to start. Wouldn’t it be easier if this behavior was handled by a system? That’s how Kubernetes comes to the rescue! Kubernetes provides you with a framework to run distributed systems resiliently. It takes care of scaling and failover for your application, provides deployment patterns, and more. For example, Kubernetes can easily manage a canary deployment for your system.

Kubernetes provides you with:

Service discovery and load balancing
Storage orchestration
Automated rollouts and rollbacks
Automatic bin packing
Self-healing
Secret and configuration management

What is Ansible?

Ansible is a configuration management system written in Python using a declarative markup language to describe configurations. It is used to automate software configuration and deployment.

Ansible Architecture :

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Ansible Playbooks :

Ordered lists of tasks, saved so you can run those tasks in that order repeatedly. Playbooks can include variables as well as tasks. Playbooks are written in YAML and are easy to read, write, share and understand.

Inventory :

A list of managed nodes. An inventory file is also sometimes called a “hostfile”. Your inventory can specify information like IP address for each managed node. An inventory can also organize managed nodes.

Let’s Begin…

We don’t have any hosts or instances running ak-2

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Launching EC2 Instances using Ansible with dynamic inventory :

Create Role :

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ansible-galaxy init ec2

In tasks file :

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ec2:
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         key_name: "{{ key_name }}"
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         instance_type: "{{ instance_type }}"
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         image: "{{ image_id }}"
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         wait: yes
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         count: "{{ count }}"
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         #         instance_tags:
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         #       name: "sample_os"
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         vpc_subnet_id: "{{ subnet_id }}"
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         assign_public_ip: yes
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         state: present
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         region: "{{ region }}"
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         group_id: "{{ sg_group_id }}"
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         aws_access_key: "{{ aws_access_key }}"
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         aws_secret_key: "{{ aws_secret_key }}"
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         instance_tags:
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             Name: "{{ item }}"
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  loop: "{{ OS_name }}"

In vars file :

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aws_secret_key: "aws_secret_key"
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key_name: "testing"
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image_id: "ami-038f1ca1bd58a5790"
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count: 1
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subnet_id: "subnet-52bc140d"
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region: "us-east-1"
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sg_group_id: "sg-0639b0dd0a69545ea"
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instance_type: "t2.micro"
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OS_name:
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     - "K8S_Master"
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     - "K8S_Node1"
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     - "K8S_Node2"
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>>> In playbook setup.yml :
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- hosts: localhost
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  gather_facts: False
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  #vars_files: secret.yml
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  roles:
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  - name: "EC2 Launch"
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    role: /root/task23/k8s/ec2/

Run the playbook :

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ansible-playbook setup.yml

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Instances launched and hosts file is been updated

Setting Up Master Node and Worker Nodes

In Master Node,

Create Role :

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ansible-galaxy init k8s_master

In tasks file :

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- name: "Creating Repo for Kubernetes"
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  copy:
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      src: kubernetes.repo
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      dest: /etc/yum.repos.d/kubernetes.repo
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- name: "Installing Software"
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  package:
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      name: "{{ item }}"
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      state: present
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  loop: "{{ package_name }}"
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- name: "Starting services"
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  service:
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      name: "{{ item }}"
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      state: started
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  loop: "{{ package }}"
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- name: "Changing driver to systemd"
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  copy:
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      src: daemon.json
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      dest: /etc/docker/daemon.json
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- name: "Restart Docker Services"
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  service:
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      name: docker
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      state: restarted
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- name: "Pulling Images"
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  shell: kubeadm config images pull
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- name: "Bridge to 1"
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  shell: echo "1" > /proc/sys/net/bridge/bridge-nf-call-iptables
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- name: "kubeadm init"
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  shell: kubeadm init --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=NumCPU --ignore-preflight-errors=Mem
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  ignore_errors: yes
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- name: "Creating .kube directory"
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  file:
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      path: $HOME/.kube
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      state: directory
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- name: "Copying file"
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  shell: cp  -i  /etc/kubernetes/admin.conf  $HOME/.kube/config
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- name: "Changing Owner Permissions"
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  shell: chown $(id -u):$(id -g) $HOME/.kube/config
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- name: "Setting up Flannel"
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  shell: kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
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  changed_when: False
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- name: "Token Creation"
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  shell: kubeadm  token create --print-join-command
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  register: token
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- name: "Printing Token"
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  debug:
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      var: token.stdout

In vars file :

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package_name:
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    - "docker"
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    - "kubelet"
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    - "kubeadm"
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    - "kubectl"
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    - "iproute-tc"
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package:
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    - "docker"
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    - "kubelet"

In Worker Nodes,

Create Role :

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ansible-galaxy init k8s_nodes

In tasks file :

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- name: "Creating Repo for Kubernetes"
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  copy:
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          src: kubernetes.repo
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          dest: /etc/yum.repos.d/kubernetes.repo
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- name: "Installing Software"
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  package:
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          name: "{{ item }}"
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          state: present
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  loop: "{{ package_name }}"
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- name: "Starting services"
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  service:
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          name:  "{{ item }}"
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          state: started
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  loop: "{{ package }}"
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- name: "Changing driver to systemd"
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  copy:
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          src: daemon.json
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          dest: /etc/docker/daemon.json
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- name: "Restart Docker Services"
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  service:
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          name: docker
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          state: restarted
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- name: "Bridge to 1"
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  shell: echo "1" > /proc/sys/net/bridge/bridge-nf-call-iptables
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- name: "Using token"
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  shell: "{{ token }}"
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>>> In vars file :
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package_name:
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        - "docker"
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        - "kubelet"
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        - "kubeadm"
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        - "kubectl"
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        - "iproute-tc"
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package:
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        - "docker"
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        - "kubelet"

In playbook k8s_setup.yml :

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- hosts: "tag_Name_K8S_Master"
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  roles:
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      - name: "K8S Master"
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        role: /root/k8s/k8s_master
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- hosts: ["tag_Name_K8S_Node1", "tag_Name_K8S_Node2"]
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  vars_prompt:
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      - name: token
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        prompt: "Enter token :"
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        private: no
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  roles:
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      - name: "K8S_Nodes"
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        role: /root/k8s/k8s_nodes