Gouranga's Tech Blog: Jenkins setup

Jenkins is built so that it is extensible over any environment and platform for faster development, testing, and deployment. It is more adaptable thanks to its sizeable plug-in library, which allows for creating, deploying, and automating across various platforms. Jenkins, as well as its plugins, are written in Java

-- Jenkins is a web based application and runs on Java.
-- runs on port 8080

Note: For testing AWS EC2 system used.

URL to find all installation steps:

https://www.jenkins.io/download/
Choose - Download Jenkins 2.375.3 LTS

https://pkg.jenkins.io/redhat-stable/

-- Install Java

# yum install fontconfig java-11-openjdk -y
# sudo amazon-linux-extras install java-openjdk11 -y

-- Verify Java version

# java -version
openjdk version "11.0.18" 2023-01-17 LTS
OpenJDK Runtime Environment (Red_Hat-11.0.18.0.10-1.amzn2.0.1) (build 11.0.18+10-LTS)
OpenJDK 64-Bit Server VM (Red_Hat-11.0.18.0.10-1.amzn2.0.1) (build 11.0.18+10-LTS, mixed mode, sharing)
#
# which java
/usr/bin/java

-- find the Java installation location

# cd /bin
# ls -l
Found below soft link. here is our java location
java -> /etc/alternatives/java
and the comlete patch of Java is:
/usr/lib/jvm/java-11-openjdk-11.0.18.0.10-1.amzn2.0.1.x86_64/

]# pwd
/usr/lib/jvm/java-11-openjdk-11.0.18.0.10-1.amzn2.0.1.x86_64

-- here you can find how many java versions have been installed in your machine

# cd bin
# pwd
/usr/lib/jvm/java-11-openjdk-11.0.18.0.10-1.amzn2.0.1.x86_64/bin
# sudo update-alternatives --config java
There is 1 program that provides 'java'.
Selection Command
-----------------------------------------------
*+ 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.18.0.10-1.amzn2.0.1.x86_64/bin/java)
Enter to keep the current selection[+], or type selection number:

-- Export Java home and path

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-11.0.18.0.10-1.amzn2.0.1.x86_64
export PATH=$JAVA_HOME/bin:$PATH

-- Test Java working or not

# cd /home/ec2-user/
# wget -O /etc/yum.repos.d/jenkins.repo https://pkg.jenkins.io/redhat-stable/jenkins.repo
# rpm --import https://pkg.jenkins.io/redhat-stable/jenkins.io.key
# yum install jenkins -y
...
Installed:
jenkins.noarch 0:2.375.3-1.1
Complete!

-- Start Jenkins

ec2-user]# service jenkins start
Starting jenkins (via systemctl): [ OK ]

-- Configure auto start of jenkins when system reboot

# chkconfig jenkins on

-- Note : you ll find all jenkins information related from /etc/sysconfig/jenkins file.

cd /etc/sysconfig
cat jenkins
Default user: jenkins
-- Jenkins configuration file
# cd /var/lib/jenkins
# cat config.xml

-- (part-1)Lunch Jenkins page
-- in browser

http://<host-name/ip>:8080/

Jenkins page will be displayed but it ll ask admin password from installation location

# cat /var/lib/jenkins/secrets/initialAdminPassword
47319bd7272f4b04a60dd8e01e29ea69

Copy the password and paste in password section and press continue. It may take some time to complete the plugin installations

(go-to -> part-2) Here meantime install git and complete maven setup

-- install git

# yum install git -y

-- Setup maven

About maven :

Maven is a build automation tool used primarily for Java projects. Maven can also be used to build and manage projects written in C#, Ruby, Scala, and other languages. maven is a product of apache foundation. light weighted as compare to ant.

1) Binary tar.gz archive apache-maven-3.9.0-bin.tar.gz
2) Binary zip archive apache-maven-3.9.0-bin.zip

-- create installation directory for maven

# mkdir /opt/maven
# cd /opt/maven

-- copy link of "apache-maven-3.9.0-bin.tar.gz" and use wget to download

# wget https://dlcdn.apache.org/maven/maven-3/3.9.0/binaries/apache-maven-3.9.0-bin.tar.gz
# ls -l
-rw-r--r-- 1 root root 9024147 Jan 31 15:20 apache-maven-3.9.0-bin.tar.gz

-- extract the tar.gz

maven]# tar -xvzf apache-maven-3.9.0-bin.tar.gz
# ls
apache-maven-3.9.0 apache-maven-3.9.0-bin.tar.gz
# mv apache-maven-3.9.0 maven
# ls
apache-maven-3.9.0-bin.tar.gz maven
# ls maven/
bin boot conf lib LICENSE NOTICE README.txt

-- setup maven variable

maven]# M2_HOME=/opt/maven/maven
maven]# M2=/opt/maven/maven/bin

# export M2_HOME M2
# PATH=$PATH:$JAVA_HOME:$M2_HOME:$M2

-- Now check the maven version

# mvn --version
Apache Maven 3.9.0 (9b58d2bad23a66be161c4664ef21ce219c2c8584)
Maven home: /opt/maven/maven
Java version: 11.0.18, vendor: Red Hat, Inc., runtime: /usr/lib/jvm/java-11-openjdk-11.0.18.0.10-1.amzn2.0.1.x86_64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.10.167-147.601.amzn2.x86_64", arch: "amd64", family: "unix"
[root@ip-172-31-16-110 maven]#

-- (part-2): Now you can continue to configure jenins web page setup

skip user creation go with default admin account as of now
start using jenkins
Now you ll have welcome/ first page of jenkins

-- Now chnage the admin user password:

Click on admin drop down --> configure --> go to password section --> use new password --> Save
user : admin
password : xxxxxx

Note: from url you can stop/ start and restart jenkins

e.g.,
http://<ip-address>:8080/restart

-- Let us do some configuration change and then we can restart Jenkins

From Jenkins Home page --> click on "Manage Jenkins" --> "Global tool configuration"

Go to JDK section:

here you type your JDK location ( this is JAVA_HOME)
Use : JAVA_HOME
path : /usr/lib/jvm/java-11-openjdk-11.0.18.0.10-1.amzn2.0.1.x86_64