Traefik #
Traefik is a reverse proxy, used by Kamal for zero-downtime deployments.
We start an instance on the hosts in it’s own container.
During a deployment:
- We start a new container which Traefik automatically detects due to the labels we have applied
- Traefik starts routing traffic to the new container
- We force the old container to fail it’s healthcheck, causing Traefik to stop routing traffic to it
- We stop the old container
Traefik settings #
Traekik is configured in the root configuration under traefik.
traefik:
Image #
The Traefik image to use, defaults to traefik:v2.10
image: traefik:v2.9
Host port #
The host port to publish the Traefik container on, defaults to 80
host_port: "8080"
Disabling publishing #
To avoid publishing the Traefik container, set this to false
publish: false
Labels #
Additional labels to apply to the Traefik container
labels:
traefik.http.routers.catchall.entryPoints: http
traefik.http.routers.catchall.rule: PathPrefix(`/`)
traefik.http.routers.catchall.service: unavailable
traefik.http.routers.catchall.priority: "1"
traefik.http.services.unavailable.loadbalancer.server.port: "0"
Arguments #
Additional arguments to pass to the Traefik container
args:
entryPoints.http.address: ":80"
entryPoints.http.forwardedHeaders.insecure: true
accesslog: true
accesslog.format: json
Options #
Additional options to pass to docker run
options:
cpus: 2
Environment variables #
env:
...