[spec] Provide a monoclectl script to manage a deployment

[TristanCacqueray]

12. Deployment of monocle services

• Date: 2021-08-09

Context and Problem Statement

There are two strategies to deploy the Monocle services:

• docker-compose (and soon kubectl apply), or,
• shell scripts to start the service on the local host.

We would like to use a single strategy to provide a consistent experience between local dev and production deployment.

Considered Options

• Nix
• Containers

Decision Outcome

Chosen option: "Containers", because it comes out best (see below).

Positive Consequences

• We simplify the deployment and contributor story.
• We improve the developer experience by offering a production like environment.

To achieve that we provide a monoclectl command to manage the service, for example using podman, compose or kubernete. The command feature three functions:

• deploy to start the service using the existing images.
• develop to start the service using the local source and development images.
• build to build the images.

Negative Consequences

• Increased disk space requirement.

Pros and Cons of the Options

Nix

• Bad, because it is not readily available.

Containers

• Bad, because it needs lot of diskspace.
• Good, because it is the target environment.

[TristanCacqueray]

To realize this spec, I suggest these 2 stories:

• [ ] Minimal monoclectl devel working with kind to validate hot-reload.
• [ ] monoclectl build to replace docker-compose build.
• [ ] monoclectl compose deploy to replace docker-compose.yml.img.

Then assuming this is working as expected, we can finish the migration:

• [ ] Use monoclectl in the CI.
• [ ] Publish the compose/kubernetes configuration with the release.
• [ ] Remove the Dockerfiles and compose/kubernetes configuration from the repo.