Service Delivery: The Build Phase - The Practice of Cloud System Administration - page 192

Chapter 9. Service Delivery: The Build Phase
And they're certainly not showing any signs that they are slowing.
—Willy Wonka
Service delivery is the technical process of how a service is created. It starts with source
code created by developers and ends with a service running in production. The system that
does all of this is called the service delivery platform . It includes two major phases: build
and deploy. The build phase starts with the software source code and results in installable
packages. That phase is covered in this chapter. The deployment phase takes those pack-
ages, readies the service infrastructure (machines, networks, storage, and so on), and pro-
duces the running system. The deployment phase is covered in Chapter 10 .
The service delivery flow is like an assembly line. Certain work is done at each step.
Tests are performed along the way to verify that the product is working correctly before be-
ing passed along to the next step. Defects are detected and monitored.
The faster the entire process can run, the sooner the test results are known. However,
comprehensiveteststakealongtime.Thereforetheearliertestsshouldbethefastest,broad-
est tests. As confidence builds, the slower, more detailed tests are done. This way the most
likely failures happen early on, removing the need for the other tests. For example, the early
stages compile the software, which is sensitive to easy-to-detect syntax errors but provides
little guarantee that the software works. Testing performance, security, and usability can be
the most time consuming. Manual tests are saved for the end, after all other failures have
been detected, conserving manual labor.