devops-cert_task

Certification task of the DevOps Engineer course

DevOps School

Jenkins pipeline to build and deploy a web application on AWS EC2 resources. One instance builds an application, other one starts it.

Pipeline scheme

Pipeline description

Deploy

• 0 - Jenkins pulls this repository and processes Jenkinsfile
• 1 - Terraform deploys an infrastructure on AWS EC2: two instances (Builder and Webserver)
• 2 - Ansible configures instances
• 3 - Docker builds an application on the Builder instance
• 3a - Docker pushes an artifact container to AWS ECR repository
• 4 - Docker cleans containers on the Webserver instance
• 4a - Docker pulls an artifact from AWS ECR repository and start it

Docker on the Jenkins host uses ssh endpoint to work with remote docker-socket

Destroy

Terraform just destroy AWS EC2 instances (Builder and Webserver). AWS ECR repository is not touched.

Parameters

• appVersion is a version of the application (default is 1.0)
• ecrHost is a hostname of ECR (default is empty)
• autoApprove is true or false (default), automatically run Terraform apply after generating plan or user approvement is required
• destroy is true or false (default), destroy Terraform build or not

Files

• Jenkinsfile (pipeline)
• *.tf (Terraform files)
• prepare-instances.yml (Ansible playbook)
• Dockerfile, app.py, requirements.txt (Python application)

Application

Just a simple Hello world web server based on the python flask. It shows version that set by Jenkins parameter appVersion.

Usage

1. Install aws cli, terraform, ansible, Jenkins (plugins: SSH Agent, Ansible, Terrafotm)

2. Generate ssh key and import it to the AWS EC2

   ssh-keygen -t rsa -C "aws-ec2-key" -f ~/.ssh/aws-ec2-key
   aws ec2 import-key-pair --key-name devops-cert_task-key \
       --public-key-material fileb://~/.ssh/aws-ec2-key.pub

3. Create ECR repository

   aws ecr create-repository --repository-name cert_task

4. Create Jenkins job

   Dashboard -> New job -> type Pipeline, name devops-cert_task
   Pipeline Definition: Pipeline script from SCM, Git
   Repository URL: https://github.com/LovingFox/devops-cert_task.git

5. Create Jenkins credentials for ssh

   Kind: SSH Username with private key
   ID: AWS_UBUNTU_INSTANCE_SSH_KEY
   Username: ubuntu
   Key:

   cat ~/.ssh/aws-ec2-key

6. Create Jenkins credentials for AWS ECR repository

   Kind: SSH Username with private key
   ID: AWS_ECR_CREDENTIALS Username: AWS
   Password:

   aws ecr get-login-password

7. Create Jenkins credentials for AWS API

   Kind: Secret text
   ID: AWS_ACCESS_KEY_ID
   Secret: <Your AWS Access Key ID>

   Kind: Secret text
   ID: AWS_SECRET_ACCESS_KEY
   Secret: <AWS Secret Access Key>

8. Start Jenkins job by GUI or by cli:

   java -jar jenkins-cli.jar build -v -f devops-cert_task \
       -p autoApprove=true -p appVersion=1.0 \
       -p ecrHost=657846606580.dkr.ecr.eu-central-1.amazonaws.com

   657846606580.dkr.ecr.eu-central-1.amazonaws.com is just an example hostname of ECR, change it by yours

9. Check the application is working:

   cutl http://curl http://<host name>.<region>.compute.amazonaws.com

   URL of the webserver is prined at the end of the Jenkins job

10. Destroy the infrastructure by GUI or by cli:

    java -jar jenkins-cli.jar build -v -f devops-cert_task -p destroy=true