DevOps Classroomnotes 26/Feb/2023

Installing Maven

• Maven requires Java to be installed.
• Java:
  • Distributions:
    • OpenJDK
    • Oracle JDK
    • IBM JDK
    • Amazon Corretto JDK
  • Versions:
    • 8
    • 11
    • 17
    • 19
• Environmental Variables:
  • PATH
  • JAVA_HOME
  • M2_HOME
• JAVA Installation

# OpenJDK 8
sudo apt update
sudo apt install openjdk-8-jdk -y
java -version

• Maven Installation

sudo apt update
sudo apt install maven -y
mvn --version

* Building a sample application using maven Refer Here for game of life code
* This project requires jdk 8
* To
* compile the code: mvn compile
* run the automated tests: mvn test
* create the package: mvn package
* Lets try to build a project spring petclinic Refer Here. This project requires JAVA 17
* When we were compiling, testing and packaging maven is downloading lot of stuff what is that?

* Maven will download all the necessary dependencies to compile/package/test from a maven central repository Refer Here and it downloads to M2_HOME which is by default <HOME-DIR>/.m2 which is referred as local repository.

• Maven Lifecycle Phases
  • compile: Will create .class files
  • test: will run unit tests
  • package: will create package (jar/war)
  • install: will copy the project which you have build to the local repository. Along with jar/war files a pom also gets copied

Jenkins

• Jenkins is an open source CI/CD Engine.
• Jenkins:
  • Using Package managers on Linux
  • Docker
  • Windows
  • WAR
• Lets install Jenkins Refer Here
• For installing in ubuntu Refer Here
• Lets install LTS (Long Term Support Version)

sudo apt-get update
sudo apt-get install openjdk-17-jdk -y
curl -fsSL https://pkg.jenkins.io/debian-stable/jenkins.io.key | sudo tee \
  /usr/share/keyrings/jenkins-keyring.asc > /dev/null
echo deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc] \
  https://pkg.jenkins.io/debian-stable binary/ | sudo tee \
  /etc/apt/sources.list.d/jenkins.list > /dev/null
sudo apt-get update
sudo apt-get install  jenkins -y

• After installing jenkins a user jenkins got created with
  • /var/lib/jenkins as Home directory
  • /bin/bash as default shell
• Now access jenkins using http://<publicip>:8080
• copy the inital secret and click on continue
  
  
  
• Create an admin user
  
  
  
  

First Project to display some system information

• Lets create a Jenkins project which displays
  • username
  • current working directory
  • all the environmental variables
• Lets start by create a Jenkins project (Freestyle)
  
• Now navigate to build steps
  
  
  
  
  
  
• Now change the invoke shell steps to something as shown below
  
• Build the jenkins job
  
  

Create a Jenkins Project to build spring petclinic

• Manual steps

git clone https://github.com/spring-projects/spring-petclinic.git
cd spring-petclinic
mvn package

• Create a Jenkins job with name spc and in build steps invoke shell and execute the following

git clone https://github.com/spring-projects/spring-petclinic.git
cd spring-petclinic
mvn package

* Install maven and rerun the same job

Exercise

• Install Jenkins on a ubuntu vm
• Try to build game of life using jenkins free style project mvn package
• Refer Here for the the project

Jenkins Projects

• Jenkins has 3 project types (majorly)
  • Free Style: These projects are UI Based.
  • Scripted Pipeline
  • Declarative Pipeline