Jenkins part4

 Jenkins part4

Class 24th Jenkins May 15th

• Variables & Parameters in Jenkins project 
• Pipeline structure & setup in Jenkins

(Some time we have to pass some inputs to jenkins job at runtime)

In Jenkins, parameters allow you to customize and control how a build run by  providing input values at runtime.There are several types of parameters you can use in a Jenkins project
Types of parameters in Jenkins

• String parameter
• Multi-line string parameter
• Choice parameter
• File parameter
• Password parameter
• Boolean parameter

Practical

Create one job Free style project 

Step1:  String parameter

Create Job >ccitvar >Freestyle project > Check This project is parameterized 

[root@ip-10-0-1-137 ccitvar]# pwd

/var/lib/jenkins/workspace/ccitvar

[root@ip-10-0-1-137 ccitvar]# ls -lrt

total 0

-rw-r--r-- 1 jenkins jenkins 0 May 24 12:49 ccit.txt

-rw-r--r-- 1 jenkins jenkins 0 May 24 12:54 aws.txt

-rw-r--r-- 1 jenkins jenkins 0 May 24 12:54 Devops.txt

Step2:  Multi-line string parameter

[root@ip-10-0-1-137 ccitvar]# ls -rlt

total 0

-rw-r--r-- 1 jenkins jenkins 0 May 24 13:10 GCP.txt

-rw-r--r-- 1 jenkins jenkins 0 May 24 13:10 Devops

-rw-r--r-- 1 jenkins jenkins 0 May 24 13:10 Azure

-rw-r--r-- 1 jenkins jenkins 0 May 24 13:10 AWS

Step3:Choice parameter

Build parameter list 

[root@ip-10-0-1-137 ccitvar]# ls -lrt

total 0

-rw-r--r-- 1 jenkins jenkins 0 May 24 13:17 Azure.txt

Step4: File parameter This Upload your files

Choose you file in you laptop and build upload some text file ,it will created with given file name

Placed 

[root@ip-10-0-1-137 ccitvar]# ls -rlt

total 0

-rw-r--r-- 1 jenkins jenkins 0 May 24 13:21 script.sh

Pipeline setup in Jenkins 

Jenkins pipeline is a combination of plugins that Support integration and implementation of continuous delivery pipelines

A pipeline is a group of events interlinked with each other in sequence 

There are two types of Jenkins pipeline syntax used for defining you Jenkins file:

•  Declarative pipe line (Recommeded)

Easier to read and maintained 
Uses as structure pipe line {} block
Best for simple CI/CD pipline 
Why we use declaration (Simple and structured,built-in error handling, Best for CI/CD use cases)

•  Scripted (Most Felxible)

Uses node {} instead of pipeline{}

Provide more control (eg. loops,Conditionals)

suitable for complex automation workflows

why user scripted(more control with loops & conditionals,Supports custom logic (id-else,try-catch)

,Best for advanced users & dynamic workflows)

Free style Project : only select save Command and build

Pipeline  : Here we write scripts 

Code->Build->Test->Deploy

Declarative (PASSS)

  Newitem ->Name ->Pipeline ->Save

 pipeline {

  agent any (Where you build need perform,your server or any other server Slave concept)

     stages {

               stage ("code"){

                            steps {

                                           Action (Git)

                          

                                      }

                           

                          }

                    }

            }

P-Pipeline A- Agent S -Stages -Stage -Steps

Step5: create job in  ccitpipelinejob

pipeline {

    agent any

    stages {

        stage('dev') {

            steps {

               sh "sudo yum install -y httpd"

               sh "sudo systemctl start httpd"

               sh "sudo git clone https://github.com/cloudcomputingintelugu/ccitwebsite.git"

               sh "sudo cp -r ccitwebsite/* /var/www/html"

            }

        }

    }

}

Build will failed ,Due to Jenkins don't have direct root user permissions install the softwares

Started by user admin

[Pipeline] Start of Pipeline
[Pipeline] node
Running on Jenkins

 in /var/lib/jenkins/workspace/ccitpipelinejob
[Pipeline] {
[Pipeline] stage
[Pipeline] { (dev)
[Pipeline] sh
+ sudo yum install -y httpd
We trust you have received the usual lecture from the local System Administrator. 
It usually boils down to these three things:ERROR: script returned exit code 1
Finished: FAILURE

Step6: Add Jenkins give permission to 

[root@ip-10-0-1-69 ~]#sudo -i

[root@ip-10-0-1-69 ~]# sudo visudo

## Read drop-in files from /etc/sudoers.d (the # here does not mean a comment)

jenkins ALL=(ALL) NOPASSWD: ALL

#includedir /etc/sudoers.d

Step7:Build Success

Step8: Git simple web page file hosted successfully to the server 

[root@ip-10-0-1-69 ccitwebsite]# ls -lrt

total 44

-rw-r--r-- 1 root root   789 May 25 07:21 readme.txt

-rw-r--r-- 1 root root 40878 May 25 07:21 index.html

drwxr-xr-x 8 root root    77 May 25 07:21 assets

Step9:Web page open successfully hosted 

--Thanks