One of my team member is assigned to install and configure "jenkins" on our server so out of curiosity, I asked what is this now ?? but didn't get a satisfactory answer :-) so I thought of having my hand dirty with it. Here, I am sharing whatever I learn.
What is Jenkins:-
Wikipedia sources says, Jenkins is an open source automation server written in Java. Jenkins helps automating the non-human part of the whole software development process, with now common things like Continuous Integration, but by further empowering teams to implement the technical part of a Continuous Delivery.
What is Continuous Integration & Continuous Delivery:-
CI is a process that most developers follow to keep their code base intact. It's mostly a common practice when you work in a group environment. For example, an analogy for this would be constructing a new home. There will be multiple contractors working on the site. So, if we have installed the window glasses and the paint person comes in and paints the house there are high chances that he will drop some paint on the glasses or end up breaking the glass. So, the inspector comes and checks it every day to see if something broke. The same process is applied for constructing a new code. CI system gathers all your code from different developers and makes sure it compiles and build fine. This is good. But, not complete. I will get to that once I complete talking about Jenkins.
Jenkins is the inspector in the analogy. Jenkins is nothing but a middle man between your code repo and your build server. It checks for changes on your server every few minutes. If it found them, it gathers them and sends them to your build server. That's what Jenkins is.
Basically Continuous Integration is the practice of running your tests on a non-developer machine automatically everytime someone pushes new code into the source repository.
This has the tremendous advantage of always knowing if all tests work and getting fast feedback. The fast feedback is important so you always know right after you broke the build (introduced changes that made either the compile/build cycle or the tests fail) what you did that failed and how to revert it.
If you only run your tests occasionally the problem is that a lot of code changes may have happened since the last time and it is rather hard to figure out which change introduced the problem. When it is run automatically on every push then it is always pretty obvious what and who introduced the problem.
Built on top of Continuous Integration are Continuous Deployment/Delivery where after a successful test run your instantly and automatically release the latest version of your codebase. Makes deployment a non-issue and helps you speed up your development.
Jenkins offers the following major features out of the box, and many more can be added through plugins:
Developer time is focused on work that matters — Much of the work of frequent integrations is handled by automated build and testing systems, meaning developer time isn't wasted on large-scale error-ridden integrations.
Software quality is improved — Any issues are detected and resolved almost immediately, keeping software in a state where it can be safely released at any time.
Faster Development - Integration costs are reduced both because serious integration issues are less likely and because much of the work of integration is automated.
Easy installation: Just run java -jar jenkins.war, deploy it in a servlet container. No additional install, no database. Prefer an installer or native package? We have those as well.
Easy configuration: Jenkins can be configured entirely from its friendly web GUI with extensive on-the-fly error checks and inline help.
Rich plugin ecosystem: Jenkins integrates with virtually every SCM or build tool that exists.
Extensibility: Most parts of Jenkins can be extended and modified, and it's easy to create new Jenkins plugins. This allows you to customize Jenkins to your needs.
Distributed builds: Jenkins can distribute build/test loads to multiple computers with different operating systems. Building software for OS X, Linux, and Windows? No problem.
Check out the part 2 for Installation.
Sources:
https://jenkins.io/ https://en.wikipedia.org/wiki/Jenkins_(software) http://stackoverflow.com https://www.quora.com
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