Use Case: Create simple specification for dockerd configuration file (daemon.json)

Summary

• Scope: spec
• Level: Developer Goal
• Actors: Dev-Ops Engineer
• Brief: This use case introduces a simple specification for a part of the dockerd configuration file (daemon.json).

Scenarios

• Precondition: The Dev-Ops Engineer has a working setup for docker and the daemon dockerd.
• Main success scenario:
  • The Dev-Ops Engineer wants to write a specification for the default runtime in the dockerd configuration.
  • The configuration key is default/runtime.
  • The configuration key uses type, description and default as metakeys.
  • The keys are all stored for the spec namespace.
• Alternative scenario: None.
• Error scenario:
  • Wrong metakeys are used (yielded as error to the user).
• Postcondition: The keys are all stored for the spec namespace..
• Non-functional Constraints: None.

Example

The default runtime configuration for the dockerd could look like:

[default/runtime]
meta:/type = string
meta:/description = Default OCI runtime for containers
meta:/default = runc

In case the key default/runtime does not exist, spec plugin creates a default key with value runc in the default namespace.

For the full specification of the dockerd configuration file see dockerd-spec.