Declare the process lifecycle
install prepares dependencies. build is an optional command executed after installation. start runs the service. build must be a string, not a { dockerfile: ... } or { image: ... } mapping.
Put environment assignments in env. The incremental runtime executes its start command through Bash, while legacy/image startup has different command handling. For portable manifests, avoid relying on inline shell assignments or implicit expansion; use env and a checked-in script for complex startup logic.
Keep paths portable
Incremental releases run in managed release directories. Use relative application paths and removeworkingDirectory; that field is rejected for incremental deployment. Write mutable data to an explicit volume, outside the managed code directory.
Verify preparation and startup
Deploy locally, inspect the release logs, and check app health. A successful install does not establish thatstart exists or listens on the right port. Missing binaries, incompatible base images, and insufficient workspace resources need correction before retrying.
For a kind: cli app, omit service port and start, and declare an executables map or health.command so incremental deployment can verify its entrypoint. See application fields.