Fundamentals

Everything in Kardinal centers around flows.

A flow in Kardinal is an ephemeral environment, containing a "development version" of your application. We call them "flows" because they are defined by a distinct flow of traffic through a shared development cluster.

Once Kardinal is installed and an application is deployed, developers can create a flow with:

kardinal flow create <service-name> <their/new-dev-image>

Kardinal will deploy the <their/new-dev-image> image alongside the baseline version of the service, and that developer will be able to interact with the application as if it was using their version of their service.

As your team onboards to Kardinal, you will be able to create flows with escalating levels of configurability:

1. Single-service flows: deploy a single service to test a new version of a service
2. Multi-service flows: deploy a set of services together to test a larger feature change involving multiple services
3. State-isolated flows: deploy a set of services together with new, isolated state (dbs, caches, queues) to test database migrations or other state-layer changes
4. Full application flows: deploy an independent, full application with its own state layer for completely isolated end-to-end testing