Nicolas De Loof
452c7a6981
The plan learns the start vocabulary — inert until a caller opts in (ReconcileOptions.Scope, zero value keeps today's create-only plans byte-identical): - OpWaitCondition, one node per (awaited service, condition), deduplicated across dependents like networkNodes deduplicates networks; required:false marks the shared node best-effort, one required dependent upgrades it. service_started needs no node — a plain DAG edge to the dependency's chain end expresses it. Health is deliberately re-observed at execution time: the plan encodes what to wait for, never a stale observation. - OpRunPreStart, emitted at plan time only when no replica was running at observation — the imperative gating — targeting the lowest-numbered replica. - OpRunPostStart per container, after its start. - replica chains: inject+start+post_start of replica n+1 depends on the end of replica n's chain, today's sequential start order made visible in golden plans; startChainEnds points at the chain end so a service_started dependent waits for the whole service, matching InDependencyOrder semantics. - scope Start plans starting observed exited/created containers without converging them (the future compose start); scope CreateStart appends the start phase to the create plan, start nodes resolving their target from the create node that materializes the replica (CreateNodeID, the mechanism OpRenameContainer already uses). Lifecycle parity with the imperative engine is load-bearing and golden-locked: - dependency conditions are evaluated even when nothing has to start (waitDependencies runs for every visited service before looking at what to start), so an up with everything running still fails on an unhealthy required dependency; - an exceptional-state replica takes NO start-phase node: its bare create-phase restart leaves it running when the start phase looks, so the imperative engine neither re-starts nor injects — and it gates pre_start like any running replica; - startChainEnds carries the end-of-visit node set (waits included when nothing started), so a service_started dependent begins only once the dependency's whole visit completed, matching InDependencyOrder; - under scope Start, a scale>0 service with no container at all fails the plan with startService's exact error. The "service:<name>:<number>" resource-ID format is built and parsed in one place (serviceReplicaID/serviceReplicaPrefix/startGroupID), and the replica sort deliberately carries the plan's determinism over the unordered containerNodes iteration. Golden tests only; no executor support yet and no caller passes the scope. Epic #14081, Lot 1 — reconciler (first item). Signed-off-by: Nicolas De Loof <[email protected]>
Table of Contents
Docker Compose
Docker Compose is a tool for running multi-container applications on Docker
defined using the Compose file format.
A Compose file is used to define how one or more containers that make up
your application are configured.
Once you have a Compose file, you can create and start your application with a
single command: docker compose up.
Note
: About Docker Swarm Docker Swarm used to rely on the legacy compose file format but did not adopt the compose specification so is missing some of the recent enhancements in the compose syntax. After acquisition by Mirantis swarm isn't maintained by Docker Inc, and as such some Docker Compose features aren't accessible to swarm users.
Where to get Docker Compose
Windows and macOS
Docker Compose is included in Docker Desktop for Windows and macOS.
Linux
You can download Docker Compose binaries from the release page on this repository.
Rename the relevant binary for your OS to docker-compose and copy it to $HOME/.docker/cli-plugins
Or copy it into one of these folders to install it system-wide:
/usr/local/lib/docker/cli-pluginsOR/usr/local/libexec/docker/cli-plugins/usr/lib/docker/cli-pluginsOR/usr/libexec/docker/cli-plugins
(might require making the downloaded file executable with chmod +x)
Quick Start
Using Docker Compose is a three-step process:
- Define your app's environment with a
Dockerfileso it can be reproduced anywhere. - Define the services that make up your app in
compose.yamlso they can be run together in an isolated environment. - Lastly, run
docker compose upand Compose will start and run your entire app.
A Compose file looks like this:
services:
web:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
redis:
image: redis
Contributing
Want to help develop Docker Compose? Check out our contributing documentation.
If you find an issue, please report it on the issue tracker.
Legacy
The Python version of Compose is available under the v1 branch.