jenkins.txt

Jenkins pipeline 
	- This is type of job we got in jenkins where all the configuration of the job 
	  is done through code.
	- Groovy is the language used to write pipeline jobs in jenkins.
    - The main pipeline is writen in a file called Jenkinsfile.	

Types of jenksin pipeline jobs 

scripted pipeline
	- Old way of defining jenkins pipeline job.
	- All the code /configuration is writen inside node block 
		
		node {
			

		}

		
Declarative pipeline
	- New way of defining jenkins pipeline job.
	- All the code /configuration is writen inside pipeline block 
		
		pipeline {
			
			
		}

How to define a pipeline job ? 
	1.  - We can directly write the pipeline script inside the job using inline script block.
		- It is difficult to main the versioning of job.
		
	2. we write the script in a file called Jenkinsfile and we source it from a SCM (Source code management).
		
	
Declarative pipeline
	The required block are AGENT, STAGES - STAGE, STEPS - STEPS
		pipeline {
			agent any 
			stages {
				stage('Build') {
					steps {
					
					}
				}
				stage('Test'){
					steps {
					
					}
				}
				stage('Deploy'){
					steps {
					
					}
				}
				stage('My-stage'){
					steps {
					
					}
				}	
			}
		}
		
	AGENT 
		- An agent is used to define the execution scope of the stage.
		- AGENT is used to distribute the workload of different stages.
		- each stage will be assigned with a executor based on agent configuration.
		
		Types of agent 
			any - Runs pipeline agents on any available executors.
			none - If we define agent as none at the pipeline level, it means we need to 
				   define agent at the stage level.
                 - If we want to control the execution of each stage we need to use agent 
				   as none at pipeline level and we can define agent for each stage.
				
				IQ - How to run a particular stage on a node ?	
				
			label - Both at agent and pipeline level we can use this type of agent.	
			docker - 
			
Note: Install blueocen plugin dashborad for pipeline jobs