DevOps Certification Course

Devops Session 2

Git and Github -

Git - It is software that can help to maintain repository

Github is repository

Steps to setup repository

1. install git in linux machine (yum install git)

2. Create account on github

3. generate key in linux machine (ssh-keygen)

4. copy the exact content from .ssh/id_rsa.pub in github ssh key setting (clickon dropdown on right side and click on setting and click on ssh) note- choose ssh rather than https

4. Click on new button after sign in and enter  repo name and click on create repository

  echo "# sample" >> README.md

git init

git add README.md

git commit -m "first commit"

git branch -M main

git remote add origin https://github.com/aaftabhamdani/sample.git

git push -u origin main

addinf anothew file (sample2.txt)

git add sample2.txt

git commit -m "commit msg"

git push -u origin main

DevOps Session 3

Git architecture

https://intellipaat.com/blog/wp-content/uploads/2020/04/Git-4.jpg

Git commands

1. git push - push code from local repository to remote repository

2. git add - add code to staging area

3. git status- check the status of files and folders

4. git commit - add code local repository

5. git clone - download entire repository on local

6. git checkout test - to change banch to test

7. git pull - new changes will be pool from remote to local

8. git diff sample.txt - check file content difference  from local repository to workspace

Devops Session 4

containerization- it is software base virtualization which does not require VM for every application

Docker- It is software layer on the top of base OS so that we can container on the top of docker

Setup to setup docker

1  sudo apt-get update

2. sudo apt-get install \

    ca-certificates \

    curl \

    gnupg \

    lsb-release

3. sudo mkdir -m 0755 -p /etc/apt/keyrings

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg

4. 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

5. sudo apt-get update

6. sudo chmod a+r /etc/apt/keyrings/docker.gpg

sudo apt-get update

7. sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

To run the container we require image files (dockerhub)

Commands to run docker

1. docker pull httpd  - it will use to download the docker image (httpd)

2. docker image list - it will use to see the image which is downloaded

3. docker ps - it is used to see the running container

4. To run container we used -  docker run -d -it httpd -p 80:80

     -d -- run in background

     -p  -- port

      -it -- interative

5. docker logs - to see the list of logs

6. docker rm xyz - it use to delete docker container (whicg is not running)

7. docker start xyz - start container

8. docker stop xyz - stop container

9. docker restart xyz - restart container

10. docker kill xyz - delete running container

DevOps Session 5

Run multiple sites in different containers

1. Download sample html code

2. copy it in aws instance

3. create resume folder and extract website data into it

4. Create Dockerfile and insert content

   From httpd:latest

   COPY . /usr/local/apache2/htdocs/

5. docker build -t resume_image .

6. docker run -p 80:80 -d -it resume_image

7. Create hotel folder and extract website into it

8. Create Dockerfile and insert content

   From httpd:latest

   COPY . /usr/local/apache2/htdocs/

9. docker build -t hotel_image .

10.docker run -p 8080:80 -d -it hotel_image

Commands in docker file

1. FROM - it will use to refer the another image from docker hub

2. COPY - copy the content from local machine to the container

3. ADD -  add the content from local machine to the container but it will extract tar files and download content if url is present

4. WORKDIR - it will select the directory in which we want to work

5. CMD - when you want to run any command

6. RUN - it will help to build your container

7. ENTRYPOINT - it will execute command on startup

8. CMD - it will execute command on startup

DevOps Session 6

#!/bin/bash

echo "1. Run hotel website"

echo "2. Delete hotel website"

read var

case $var in

1)

docker build  -t hotel_image $HOME

docker run --name hotel -p 80:80 -d -it hotel_image

break;;

2)

docker kill hotel

docker rm hotel

docker rmi hotel_image

break;;

*)

echo "enter correct choice"

esac

docker run -d -p 8000:8000 -p 9443:9443 --name portainer \

--restart=always \

-v /var/run/docker.sock:/var/run/docker.sock \

-v portainer_data:/data \

portainer/portainer-ce:2.9.3

DevOps session 7

Cluster - It is not posssible to depend on single system so we setup multiple systems in such a way that if first is down then second will work without downtime

Docker swarm - it is cluster service odf docker

Steps to create cluster

1. docker swarm init --advertise-addr ip_add_1st

2. docker swarm join --token SWMTKN-1-6adyuvs4e2mxrlxs4p8so1amheyfj2uzgkp3ar69pg3k6scvfa-dgxoe1vhevkcau2ufxshyp17f 172.31.46.142:2377

3. docker node ls

4.docker service create -p 80:80 --name sample --replicas=6   httpd:latest

5. Launch portrainer to check on gui

6. docker service scale sample=10

DevOps Session 8

Docker compose

It is use to handle multiple containers in once

Steps to run docker compose

1. Install Docker file and docker-compose

2. Create 2 different folders and create 2 docker files

3. Create dcker compose file (docker-compose.yml)

   version: '3.3'

services:

    hotel:

        restart: always

        build:

            dockerfile: Dockerfile

            context: ./hotel

        ports:

          - '80:80'

    resume:

        restart: always

        build:

          dockerfile: Dockerfile

          context: ./resume

        ports:

          - '8080:80'

version: '3.3'

services:

    hotel:

        restart: always

        build:

            dockerfile: Dockerfile

            context: ./hotel

        ports:

          - '80:80'

    resume:

        restart: always

        build:

          dockerfile: Dockerfile

          context: ./resume

        ports:

          - '8080:80'

    portainer:

        image: portainer/portainer-ce:latest

        ports:

          - '9443:9443'

          - '8000:8000'

        volumes:

          - portainer_data:/data

          - /var/run/docker.sock:/var/run/docker.sock

        restart: unless-stopped

volumes:

  portainer_data:

DevOps Session 9

Ansible- It is a tool of redhat which is use for deployment

Step to setup Ansible

1. Launch 3 Instance with 1 is Ansible server another is general server

2. Setup passwordless key from ansible server to another servers

   generate ssh-keygen on ansible server and place the id_rsa.pub to another servers authorized_keys file

3. write sample.yml file

   ---

- hosts: all

  become: yes

  tasks:

  - name: install yum package

    yum:

      name: http*

      state: present

  - name: start service

    service:

      name: httpd

      state: started

  - name: sample website

    copy:

      src: index.html

      dest: /var/www/html/index.html

4. execute-

  ansible-playbook sample.yaml

ansible all -m yum -a "name=unzip state=present" --become

DevOps session 10

https://docs.ansible.com/ansible/2.9/modules/list_of_all_modules.html

https://opensource.com/article/19/9/must-know-ansible-modules

https://github.com/aaftabhamdani/sample

Yaml - Its is human readable language and extension is .yaml or .yml

Ansible- Yaml is used to write playbook.

---

hosts: all

become: yes

tasks:

- name: package update

  yum:

    name:

      - a

      - b

      - c

      - d

    state: latest

when: ansible_os_family == "RedHat"

- name: package update apt

  apt:

    name: '*'

    state: latest

when: ansible_os_family == "Debian"

4. execute-

  ansible-playbook sample.yaml

DevOps session 11

https://www.devopsschool.com/blog/example-code-of-ansible-variable-with-playbook/

Inventory files- It is the file which contain the list of machines in which IP address or hostname is .

Dynamic Inventory- It is custome inventory file

You can pass custom inventory file using below command

ansible-playbook -i mydb patch.yaml

Variable- It is used to change custom value for different deployment

vars:

VAR1: 8080

VAR2: 8081

example-

---

- hosts: all

  become: yes

  vars:

    pkg_name: "httpd"

  tasks:

  - name: PAckage update

    yum:

      name: "{{ pkg_name }}"

      state: latest

---------------------------------------------------------

---

- hosts: all

  become: yes

  vars:

    pkg_name: "ssh"

  tasks:

  - name: PAckage update

    yum:

      name: "{{ pkg_name }}"

      state: latest

  - name: print variable

    debug:

      msg: "My variable is {{ pkg_name }}"

Devops Session 12

Loops- It is use to do the multiple task in one

---

- hosts: all

  become: true

  tasks:

  - name:  add users

    user:

      name: '{{ item }}'

      state: present

    loop:

      - user11

      - user12

      - user13

      - user14

      - user15

      - user16

      - user17

      - user18

Either we can use loop or with_items:

Roles-  Roles provide a framework for fully independent, or interdependent collections of variables, tasks, files, templates, and modules.

DevOps Session 14

Terraform- It is a infrastrcuture as a code (IaaC). It support more than 100 clouds. We used HCL. Develop by hashicorp.

Steps to install terraform on windows

1. Download terraform on windows

2. Open powershell or command prompt

3. ./terraform version

DevOps Session 15

Terraform output block is used to show specific output after infrastructure deployment

output "my_block" {

description = "my description"

value = ["${aws_resource.resource_name.resource_value}"]

}

terraform namespace- It is use to deploy the tf file in different enviornment

DevOps Session 16

Terraform variables

Example-

provider "aws" {

region = "ap-south-1"

}

variable "ami_id" {

description = "Insert ami id"

default = "ami-0fdea1353c525c182"

}

resource "aws_instance" "test" {

ami = var.ami_id

instance_type = "t2.micro"

key_name = "test_key"

}

output "My_instance_ElasticIP" {

description = " Public IP  of project VPC"

value       = ["${aws_instance.test.public_ip}"]

}

create terraform.tfvars file

ami_id = "ami-0fdea1353c525c183"

note if your terraform var file is not terraform.tfvars the you should use below command

terraform apply -var-file="testing.tfvars"

provider "aws" {

region = "ap-south-1"

}

variable "ins_type" {

description = "Insert instance type"

default = "t3.micro"

}

variable "key_name" {

description = "Insert key name"

default = "test_t"

}

data "ami_id" "inst1" {

most_recent = true

owners = ["self"]

filter {

  name   = "name"

  values = ["ami-0fdea1353c525c182"]

}

}

resource "aws_instance" "test" {

ami = "${ami_id.inst1.id}"

instance_type = var.ins_type

key_name = var.key_name

}

output "My_instance_ElasticIP" {

description = " Public IP  of project VPC"

value       = ["${aws_instance.test.public_ip}"]

}