Tuesday, December 8, 2020

Deploy Python App Docker Container into Amazon EKS Cluster using Jenkins Pipeline | Containerize Python App and Deploy into EKS Cluster

We will learn how to automate Docker builds using Jenkins and Deploy into AWS EKS - Kubernetes Cluster. We will use Python based container application. I have already created a repo with source code + Dockerfile. The repo also have Jenkinsfile for automating the following:


- Automating builds using Jenkins
- Automating Docker image creation
- Automating Docker image upload into Docker registry
- Automating Deployments to Kubernetes Cluster

Pre-requistes:
1. Amazon EKS Cluster is setup and running. Click here to learn how to create Amazon EKS cluster.
3. Setup Jenkins slave, install docker in it.
4. Docker, Docker pipeline and Kubernetes Deploy plug-ins are installed in Jenkins



5. Docker hub account setup in https://cloud.docker.com
6. Install kubectl on your instance


Step #1 -Make sure Jenkins can run Docker builds after validating per pre-requistes

Step #2 - Create Credentials for Docker Hub
Go to Jenkins UI, click on Credentials -->


Click on Global credentials
Click on Add Credentials


Now Create an entry for your Docker Hub account. Make sure you enter the ID as dockerhub

Step #3 - Create Credentials for Kubernetes Cluster
Click on Add Credentials, use Kubernetes configuration from drop down.


execute the below command to get kubeconfig info, copy the entire content of the file:
sudo cat ~/.kube/config


Enter ID as K8S and choose enter directly and paste the above file content and save.

Step #4 - set a clusterrole as cluster-admin

By default, clusterrolebinding has system:anonymous set which blocks the cluster access. Execute the following command to set a clusterrole as cluster-admin which will give you the required access.

kubectl create clusterrolebinding cluster-system-anonymous --clusterrole=cluster-admin --user=system:anonymous

Step # 5 - Create a pipeline in Jenkins
Create a new pipeline job.


Step # 6 - Copy the pipeline code from below
Make sure you change red highlighted values below:
Your docker user id should be updated.
your registry credentials ID from Jenkins from step # 1 should be copied

pipeline {
     agent {
         label 'myslave'
     }
        environment {
        //once you sign up for Docker hub, use that user_id here
        registry = "your_docker_hub_user_id/mypython-app"
        //- update your credentials ID after creating credentials for connecting to Docker Hub
        registryCredential = 'dockerhub'
        dockerImage = ''
    }
    stages {

        stage ('checkout') {
            steps {
            checkout([$class: 'GitSCM', branches: [[name: '*/master']], doGenerateSubmoduleConfigurations: false, extensions: [], submoduleCfg: [], userRemoteConfigs: [[url: 'https://github.com/akannan1087/myPythonDockerRepo']]])
            }
        }
       
        stage ('Build docker image') {
            steps {
                script {
                dockerImage = docker.build registry
                }
            }
        }
       
         // Uploading Docker images into Docker Hub
    stage('Upload Image') {
     steps{   
         script {
            docker.withRegistry( '', registryCredential ) {
            dockerImage.push()
            }
        }
      }
    }
   
    stage ('K8S Deploy') {
        steps {
            script {
                kubernetesDeploy(
                    configs: 'k8s-deployment.yaml',
                    kubeconfigId: 'K8S',
                    enableConfigSubstitution: true
                    )           
               
            }
        }
    }
  
    }  
}

Step # 7 - Build the pipeline
Once you create the pipeline and changes values per your Docker user id and credentials ID, click on 

Step # 8 - Verify deployments to K8S

kubectl get pods


kubectl get deployments
kubectl get services

Steps # 9 - Access Python App in K8S cluster
Once build is successful, go to browser and load balance url along with port number mentioned above
http://load_balancer_url:port_no_from_above

You should see page like below:



How to setup Jenkins slave node to run Docker Builds | Setup Jenkins Slave and Install Docker

How to configure Jenkins Slave to run Docker builds?

Create User as Jenkins
sudo useradd -m jenkins
sudo -u jenkins mkdir /home/jenkins/.ssh




Steps for installing Docker
sudo apt-get update && sudo apt install docker.io -y
 
Install Maven
sudo apt-get install maven -y
 
Add Jenkins to Docker Group
sudo usermod -aG docker jenkins
sudo newgrp docker
sudo systemctl daemon-reload
 
Restart Docker service
sudo systemctl start docker
sudo systemctl enable docker
sudo systemctl restart docker


Login to Jenkins Master and restart Jenkins service
sudo service jenkins restart
(Make sure you execute this in Jenkins Master)

Add SSH Keys from Master to Slave 

Execute the below command in Jenkins master Ec2.
sudo cat ~/.ssh/id_rsa.pub

Copy the output of the above command:

Now go to Slave node and execute the below command
sudo -u jenkins vi /home/jenkins/.ssh/authorized_keys

This will be empty file, now copy the public keys from master into above file.
Once you pasted the public keys in the above file in Slave, come out of the file by entering wq!

 Login to master node and try to SSH from Master to Slave
ssh jenkins@slave_node_ip





this is to make sure master is able to connect slave node. once you are successfully logged into slave, type exit to come out of slave.



Now copy SSH keys into /var/lib/jenkins/.ssh folder also by executing below command in Jenkins master(make sure you exited from slave by typing exit command:

sudo cp ~/.ssh/known_hosts  /var/lib/jenkins/.ssh

Register slave node in Jenkins:
Now to go Jenkins Master, manage jenkins, manage nodes.









Click on new node. give name and check permanent agent.
give name and no of executors as 1. enter /home/jenkins as remote directory.
select launch method as Launch slaves nodes via SSH.
enter Slave node ip address as Host.











click on credentials. Enter user name as jenkins. Make jenkins lowercase as it is shown.
 Kind as SSH username with private key. enter private key of master node directly by executing below command:

sudo cat ~/.ssh/id_rsa
(Make sure you copy the whole key including the below without missing anything)
-----BEGIN RSA PRIVATE KEY-----
-----
-----END RSA PRIVATE KEY-----

click Save.
select Host key verification strategy as "manually trusted key verification strategy".

Click Save.
Click on launch agent..make sure it connects to agent node.

 
That's it! Jenkins Master and Slave is configured up!

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