Warm externally-started instances

Seed a session for managed instances that start without Sablier having initiated them, keeping them running instead of stopping them on arrival.

# compose.yml
services:
  sablier:
    image: sablierapp/sablier:next
    command:
      - start
      - --provider.name=docker
      - --provider.auto-stop-on-startup=false
      - --provider.auto-warm-externally-started=true
      - --sessions.default-duration=1m
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

  managed:
    image: acouvreur/whoami:v1.10.2
    labels:
      - "sablier.enable=true"
      - "sablier.group=managed"

An externally-started managed container receives a seeded session and keeps running; once the session expires without traffic, Sablier stops it. A container with no Sablier labels is ignored.

This is the non-destructive counterpart to stopping externally-started instances. A container labelled sablier.enable=true can start without Sablier having initiated it, for example through docker compose up, a deployment tool, or a manual docker start. When that happens, Sablier seeds a session for it using the default session duration instead of stopping it. The container keeps running until that session expires without traffic, then hibernates through the normal scale-to-zero lifecycle.

    flowchart LR
    ext[Container starts externally] --> seed[Sablier seeds a session]
    seed --> warm[Kept running]
    warm -->|session expires without traffic| stop[Sablier stops it]
  

When to use it

Use this when fresh deployments should be adopted into the session lifecycle rather than killed on arrival, so a just-deployed instance stays up long enough to serve initial traffic.

Flags

• --provider.auto-warm-externally-started: continuously seed a session for managed instances that were started externally.
• --provider.auto-stop-on-startup: keep this false so already-running managed instances are not stopped at startup.
• --sessions.default-duration: how long the seeded session lasts.

See the runnable example.