00_Jenkins and CI & CD Overview
Internet ⽹ software development and publishing, has been formed ⼀ sets the standard process, the most important part is the continuous integration (Continuous integration, referred to as CI) and Continuous Delivery (Continuous delivery), continuous deployment (continuous deployment).
A. Continuous Integration
It refers to a continuous integration frequently (several times by one day) integrated into the main code, dry.
It has two main benefits:
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Errors quickly: each completed ⼀ point update, it is integrated into the main, dry, you can quickly find errors, positioning errors can ⽐ easier;
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Prevents shifting points ⽀ zoomed off the main pieces, dry place: if not often integrated, the main dry place that is a separate warranty is continually updated, will lead to the future integration of difficulty zoomed change, even ⾄ difficult to integrate.
Martin Fowler said, "Continuous Integration does not eliminate Bug, ⽽ comes in handy is to make them easier to find and correct."

After emphasizing the development of personnel on a continuous integration submitted a new code, enter immediately while ⾏ building, (unit) tests, according to test results, we can determine the new code and legacy code that can be joined to properly integrate.
II. Continuous Delivery
Continuous Delivery (Continuous delivery) refers frequently to the new version of the software, to deliver quality teams or Use households for review. If the review by, the code gets into ⽣ production stage.
Continuous delivery can be seen as continuous integration to record the next step, it is emphasized that no matter how code updates, the software can be delivered anytime, anywhere.

Continuous Delivery in continuous integration on the basis of the code of integrated deployed to closer to real when running a environment "category ⽣ production environment" (production-like environments) in. ⽐ as we complete unit testing, code can be deployed to more test the connection Staging environment database. If the code is no problem, you can continue to deploy your watch move ⽣ production environment.
III. Continuous Deployment
Continuous deployment (continuous deployment) to record the next step is a continuous delivery, by referring to the code after evaluation, automatically
moving ⽣ deployed to a production environment.
Continued deployment destination time standard is that the code can be deployed at any one time is, you can ⽣ gets into production phase.
Continuous deployment on the premise that technology can automatically complete the test, build, deploy, and other steps.

