DevOps Architecture

Project: - Install an Apache Web-server, build with Maven, Test locally/Remote & deploy on your desired option (VM/Docker/Cloud)

Description of above DevOps plan.

1. Create Maven based source code in Gitlab.

2. Create a Jenkins job which will execute below stages.

· Checkout code from Gitlab

· Build/compile the source code using Maven as a build tool.

· scan the code virtually.

· Test the code by deploying an Apache Webserver & pointing the compiled

code to it.

· After Successful testing, upload the compiled code/Artifact to
Nexus Server (centralized Server).

· Deploy to UAT/SIT/PROD using Ansible playbooks.

· Deployment will be done on Docker & further Kubernetes.

3. Nagios will monitor the above infrastructure.

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Please follow below steps to install Jenkins latest version on RHEL based VM

Prerequisites

To follow this tutorial, you will need the following:

CentOS 7 Droplet

A non-root user with sudo privileges (How To Edit the Sudoers File on Ubuntu and CentOS explains how to set this up).

All the commands in this tutorial should be run as a non-root user. If root access is required for the command, it will be preceded by sudo.

System-Specific Packages vs the WAR File

Now that you know what Jenkins is, you need to understand how it is distributed. Jenkins runs on Java and comes as a WAR file — a collection of related content comprising a web application and intended to be run on a server. However, the developers of Jenkins kindly extend its ease of use through a number of system-specific packages that allow Jenkins to run as a controlled service.

A Jenkins package is available for the Red Hat family of distributions, which includes the CentOS operating systems. However, CentOS 7 in particular is a finicky breed, so it requires a different approach. Operations that work in other Red Hat-based OSes, even other CentOS versions, tend to work differently in CentOS 7, and the potential errors that result can be difficult to debug. Since the Jenkins package is generic Red Hat, rather than being differentiated for CentOS, the likelihood of running into issues is higher than on other OSs. For this reason, we won’t run Jenkins via this package. That leaves us the WAR file running through Java, which is far less convenient, requiring us to manually start and stop it through Java.

Fortunately, there’s a way around this, and even without a package, we can work with CentOS to have it treat Jenkins like a service.

Step 1 — Installing Jenkins

There are two basic ways to install Jenkins on CentOS: through a repository, or repo, and via the WAR file. Installing from a repo is the preferred method, and it's what we'll outline first.

You'll need Java to run Jenkins (either method), so if your server doesn't yet have Java, install it with:

· Become Root on the Linux VM

· yum -y install java

In general, if you need a service or tool but you're not sure what package provides it, you can always check by running:

· yum whatprovides service

Where service is the name of the service or tool you require.

Installing from the Repo

Now, run the following to download Jenkins from the Red Hat repo:

· wget -O /etc/yum.repos.d/jenkins.repo https://pkg.jenkins.io/redhat-stable/jenkins.repo

The wget tool downloads files into the filename specified after the "O" flag (that's a capital 'O', not a zero).

Then, import the verification key using the package manager RPM:

· rpm --import https://pkg.jenkins.io/redhat-stable/jenkins.io.key

· yum upgrade -y

· yum install epel-release java-11-openjdk-devel -y

· amazon-linux-extras install epel -y

Finally, install Jenkins by running:

· yum install jenkins -y

That's it! You should now be able to start Jenkins as a service:

· systemctl start jenkins.service

Once the service has started, you can check its status:

· systemctl status jenkins.service

This will give you a fairly lengthy readout with a lot of information on how the process started up and what it's doing, but if everything went well, you should see two lines similar to the following:

Loaded: loaded (/etc/systemd/system/jenkins.service; disabled)

Active: active (running) since Tue 2015-12-29 00:00:16 EST; 17s ago

This means that the Jenkins services completed its startup and is running. You can confirm this by visiting the web interface as before, at http://ip-of-your-machine:8080.

Please follow below link to add Jenkins Slave

http://yallalabs.com/devops/how-to-add-linux-slave-node-agent-node-jenkins/

Please follow below steps to install OpenJDK & Maven on both Master & Slaves

OpenJDK

# cd /opt

# wget https://download.java.net/java/GA/jdk13/5b8a42f3905b406298b72d750b6919f6/33/GPL/openjdk-13_linux-x64_bin.tar.gz

# tar -xvf openjdk-13_linux-x64_bin.tar.gz
# /opt/jdk-13/bin/java -version

# vi /root/.bashrc
export JAVA_HOME=/opt/jdk-13/
export PATH=$PATH:/opt/jdk-13/bin

# source /root/.bashrc
# echo $JAVA_HOME
# java -version

Maven

# cd /usr/local/src
# wget https://mirrors.estointernet.in/apache/maven/maven-3/3.8.1/binaries/apache-maven-3.8.1-bin.tar.gz
# tar -xf apache-maven-3.8.1-bin.tar.gz
# mv apache-maven-3.8.1/ apache-maven/
# vi /root/.bashrc
export MAVEN_HOME=/usr/local/src/apache-maven
export PATH=${MAVEN_HOME}/bin:${PATH}
# source /root/.bashrc
# mvn --version

Go to Manage Jenkins -----> Go to Global Tool Configuration

1. Set JAVA_Home Path

2. Set Maven_Home Path