Skip to main content

Restart policies

Overview​

Restart policies in Docker help ensure that containers automatically restart under specified conditions, making deployments more resilient to failures. In a docker-compose.yaml file, you can define restart policies to control how a container behaves when it stops or encounters an issue. This tutorial explains different restart policies available in Docker Compose and provides a hands-on example using the Filebrowser image.

Understanding Restart Policies​

Docker provides four restart policies that can be configured in docker-compose.yaml under the restart directive:

  • no: The container will not restart automatically if it stops (default behavior).
  • always: Forbidden in Barbara The container will restart regardless of the reason it stopped.
  • unless-stopped: The container will restart unless it is manually stopped by the user.
  • on-failure: The container will restart only if it exits with a non-zero status, optionally specifying a maximum number of retries.

Restart Policies Forbidden in Barbara​

The option "ALWAYS" is forbidden in Barbara Edge Nodes. Do not use it.

Example Configuration​

The following docker-compose.yaml file demonstrates how to configure a restart policy for a Filebrowser container:

version: '3.8'

services:
  filebrowser:
    image: filebrowser/filebrowser:latest
    ports:
      - "8080:80"
    restart: unless-stopped

Explanation:​

  • restart: unless-stopped ensures that the container restarts automatically after a failure or system reboot but does not restart if manually stopped.

Summary​

By configuring restart policies in docker-compose.yaml, you can ensure that containers recover from failures and remain available without manual intervention. Understanding and properly setting these policies can improve the reliability of your containerized applications.