The previous chapter highlighted the Kubernetes components that comprise an Operator. From that API level up, there is inevitable complexity in developing an operator, and in managing its distribution, deployment, and lifecycle. The open-source Operator Framework is a set of abstractions and a way of thinking about operator construction and management to make it simpler.
The Operator Framework makes building operators easier by suggesting a model for iterative development, paired with a software development kit (SDK) that automates much of the repetitive implementation required for any Kubernetes API client. The Framework also provides mechanisms for deploying and managing operators. The Operator Lifecycle Manager (OLM) is an Operator that installs, manages, and upgrades other Operators. Operator Metering is a metrics system for accounting operators’ use of cluster resources. This chapter introduces these four elements.
The Operator Maturity Model sketches a way to plan the development of an Operator over several revisions, adding capabilities from a minimum viable product like installation, through lifecycle and version management, and on to whatever “complete automation” may mean for your application.
An operator can have humble origins and grow in sophistication over a series of ...