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Swarm registry

How does it work?​

Swarmlet relies on a few core modules to function properly, one of which is the internal registry. The registry is deployed as a swarm service, which means we can login from within the swarm using:

docker login localhost:5000
$ Username: <provide username configured during installation>
$ Password: <provide password configured during installation>
$ Login Succeeded

# Get the registry catalog
curl --user username:password  http://localhost:5000/v2/_catalog

Services containing a build step can store their images in the swarm registry by using the ${SWARMLET_REGISTRY} environment variable, which is injected by the deployer service before building and deploying the service.

Environment variables

You can use all environment variables used by Swarmlet, including the installation configuration variables such as $ROOT_DOMAIN or $SWARMLET_USERNAME in your project .env and entrypoint files, these will be sourced from the project root directory before deployment as well.

Using the registry​

A very simple service with a Dockerfile which image we want to store in the registry could look like this. The Swarmlet deployer_agent service will build the Dockerfile located in the project repository and push the artifacts to the internal registry if image: ${SWARMLET_REGISTRY}/app-image-name is used.

By using ${SWARMLET_REGISTRY}/my-app, an image named my-app will be built, pushed and stored in the swarm registry. This enables automatic caching of build artifacts.

./docker-compose.yml
version: "3.7"

services:
  my-app:
    build: .
    image: ${SWARMLET_REGISTRY}/my-app
    deploy:
      mode: replicated
      replicas: 1

Exposing the registry​

After installation, the registry is exposed by default. Log in using the username and password you've provided during installation. Try logging into the registry using:

docker login registry.yourdomain.com
$ Username: <provide username configured during installation>
$ Password: <provide password configured during installation>
$ Login Succeeded

Exposing the registry on a different domain​

git clone git@swarm:registry
cd registry
echo DOMAIN=yourdomain.com > .env
git add . && commit -m 'update'
git push origin master

# Wait a few moments for Traefik to update it's configuration

docker login registry.yourdomain.com
$ Username: <provide username configured during installation>
$ Password: <provide password configured during installation>
$ Login Succeeded