Always-up

Always up is a ultra-lightweight script automating the restart-on-unhealthy policy for docker containers. It regularly checks for unhealthy containers and restart them.

Installation

Using docker-compose

version: "3"

services:
  always-up:
    image: yooooomi/always-up
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      CHECK_INTERVAL: 60
      SHUTDOWN_TIMEOUT: 5

Configuration

The configuration of always-up is done through labels assigned to a container.

Using docker-compose

version: "3"

services:
  unstable_service:
    image: unstable_program
    healthcheck:
      test: ["CMD", "some_command"]
      interval: 30s
      timeout: 10s
      retries: 3
    labels:
      always-up.enabled: true

Using docker

docker run --label always-up.enabled=true unstable_program

Dependencies

It can happen that an unhealthy container has other containers depending on it (i.g a container uses the other container network)

Containers with dependencies are first stopped from the most dependant one to the least, then started again from the least dependant one to the most.

You can specify dependencies through labels too.

Using docker-compose

version: "3"

services:
  vpn:
    image: some_vpn
    healthcheck:
      test: ["CMD", "curl", "-f", "https://google.com"]
      interval: 30s
      timeout: 10s
      retries: 3
    labels:
      always-up.enabled: true

  unstable_service:
    image: unstable_program
    network_mode: container:vpn
    labels:
      always-up.enabled: true # necessary
      always-up.depends_on: vpn

always-up.enabled: true without specifying a health check will act as container always healthy.

Using docker

docker run --label always-up.enabled=true --label always-up.depends_on=vpn unstable_program