Docker-Compose Restart Policy

Question

I looked thru the docs for docker-compose and I see that Version 3 has a deploy restart policy but it's only for swarm. I tried setting restart_policy on my service but got this error:

ERROR: The Compose file './docker-compose.yml' is invalid because:
Unsupported config option for services.web: 'restart_policy'

Is there any way to set a restart policy on services created using docker-compose outside of a swarm?

Solution 1

Version 2 supports restart policies, using the restart keyword, and should work fine for you if you don't need Swarm (which you said you don't need/want).

version: '2'
services:
  web:
    image: apache
    restart: always

https://docs.docker.com/compose/compose-file/compose-file-v2/#restart

Compose format version 3 has a parameter called restart_policy, but so far as I can tell from documentation it is only valid as part of deploy, which is only used when deploying to a Swarm. So version 3 is probably not useful in your case.

Solution 2

It looks like a gap in the documentation

In 3rd version, we can still use "restart" inside services same as before in v.2 (except for deploy into swarm)

version: '3'
services:
  my-service:
    restart: on-failure:5 

https://docs.docker.com/compose/compose-file/compose-file-v3/#restart_policy

Solution 3

Even if you're NOT in swarm mode, there is an option called --compatibility which will work with restart_policy, this will attempt to restart even if you're not deploying. The only glitch, is the sub-keys of 'delay' and 'window' will be ignored. Here is an example:

version: '3.7'
services:
  build:
    context: .
    dockerfile: Dockerfile
  container_name: example
  deploy:
    restart_policy:
      condition: on-failure
      max-attempts: 3

run this command:

docker-compose -f docker-compose.yml --compatability up

Comments

[OneCricketeer]

Question was about version 3, try updating the answer? docs.docker.com/compose/compose-file/#/restartpolicy

[OneCricketeer]

I think the error in the question was because a non version 3 compose file was used

[Dan Lowe]

@cricket_007 AFAICT from docs, restart_policy is only valid inside deploy, which is only even used when doing Swarm. Since OP asked about not using Swarm, I feel my original answer should just stay as-is.

[OneCricketeer]

Version 3 says it is recommended for all new compose files. restart was simply renamed, AFAICT

[Dan Lowe]

@cricket_007 restart_policy is a sub-option of deploy, and deploy in docs says "This only takes effect when deploying to a swarm with docker stack deploy, and is ignored by docker-compose up and docker-compose run."

[cdaringe]

i don't see the :5 as a documented part of the API. did i miss it? can you clarify the intent of that?

[riverhorse]

It seems they fixed that gap in the documentation. The :5 is still not documented, and apparently is the "maximum retry count". I used it like that: restart: unless-stopped:5 and got maximum retry count cannot be used with restart policy 'unless-stopped'. I put a 0 instead of 5 and it worked

[Lokesh]

Sorry for this silly question but I didn't get what you meant by "except for deploy into swarm". Would restart: on-failure:5 work outside of swarm i.e. what I do docker-compose up in version 3?

[samayo]

does the restart mean when you launch docker via docker-compose up?? it thought doing that always restarts the daemons

[emersonwood]

The maximum retry count, while undocumented, can be found in the source code here.

[Wade Williams]

From the documentation: Do not use this in production! docs.docker.com/compose/compose-file/compose-versioning/…

[Hritik]

Now version 3 also supports restart: github.com/compose-spec/compose-spec/blob/master/…

[Magnetron]

@riverhorse it appears the gap in the documentation was unfixed.

[riverhorse]

@Magnetron yeah, it seems they did unfix it.