Service Delivery: The Deployment Phase - The Practice of Cloud System Administration - page 218

once testing is automated. If some tests are not automated, CD can deliver the release to a
beta environment used for manual testing.
10.6 Infrastructure as Code
Recall in Figure 9.1 that the service delivery platform (SDP) pattern flow has quadrants
that represent infrastructure as well as applications. The infrastructure for all environments
should be built through automation that is treated just like any other service delivered by
the SDP.
Thisapproachiscalled infrastructure as code .Likeapplication code,thecodethatde-
scribes the infrastructure is stored in the source repository, revision controlled, and tested
in a test environment before being approved for deployment in the live production envir-
onment.
Configuration code includes the automation to do configuration management as well as
any configuration files and data. Configuration management code and data are built, pack-
aged, and so on just like application software. Even images for VMs and containers can be
built and packaged.
Whentheinfrastructureascodetechniqueisdonecorrectly,thesamecodecanbuildde-
velopment, testing, and production environments. Each environment differs only in terms
of which machines to use, the number of replicas, and other settings. This minimizes the
differencebetweenthetestingandproductionenvironmentsandmakestestingmoreaccur-
ate.
Anyone should be able to build an environment for development or testing. This
lets teams and individuals operate and experiment without needing to bother operations.
Developers and QA personnel can build multiple test environments. SWEs can build their
own sandbox environments, using virtual machines on their laptops.
Infrastructure as code becomes easier to implement as hardware becomes more and
more virtual. Over time, storage, machines, and networks have all gone virtual. Storage
volumes, virtual machines, and network topologies can be created, manipulated, and deal-
located through software and controlled by APIs.
10.7 Other Platform Services
A few other services are involved in an SDP and are worth a brief mention in this chapter:
• Authentication: There needs to be some form of authentication so that the system
can restrict who can access what. In turn, security facilities are needed that provide
authentication, authorization, and accounting (AAA). Often this service consists of
LDAP plus Kerberos, Open Directory, or Active Directory.