Restart Helper

DevSpace provides a small shell script that can used as container entrypoint (PID 1 process) to start the container instead of your actual container start command.

For example, if your entrypoint would be python main.py, DevSpace would rewrite the container start command to:

/.devspace/devspace-restart-helper python main.py

This has the advantage that DevSpace (or you) can restart your application without crashing the container because normally, the python command would be the PID 1 and if that gets killed, the container will be destroyed. If the restart helper script is PID 1, we can kill the python process without impacting the container. Then, the restart helper will just restart the python command again.

Inject Restart Helper

To tell DevSpace to inject the restart helper into the container, set inject: true for the restartHelper field:

devspace.yaml

dev:
  app:
    imageSelector: ghcr.io/org/project/image
    command: ["restart", "this", "command"]
    args: ["with", "these", "args"]
    restartHelper:
      inject: true

Trigger Restarts

The restart helper per se does not do much except restarting your application if it has been killed. You can either manually kill your application to trigger a restart or you can configure DevSpace to trigger a restart automatically, e.g. when the file sync changes specific files.

Manually

You can manually trigger a restart using the devspace restart command:

devspace restart
devspace restart -n my-namespace --pod my-pod
devspace restart -n my-namespace --label-selector abc=def

You can also trigger a restart manually via kubectl:

kubectl exec my-pod -- sh -c 'PID=$(cat /.devspace/devspace-pid) && rm /.devspace/devspace-pid && kill -9 -$PID' 

Here is a more verbose version of the above kubectl exec command as it will be run inside the container:

# 1. Get the PID of your applications process
PID=$(cat /.devspace/devspace-pid)

# 2. Remove the PID file to tell the restart helper that this is an intended restart
# (otherwise the restart helper will terminate as well which will kill the container)
rm /.devspace/devspace-pid

# 3. Kill the application process group (restart helper on PID 1 will detect this and restart it again)
kill -9 -$PID

On File Sync

You can use the sync-triggered action restartContainer: true to restart your application inside the container every time DevSpace syncs files into the container.

Restart Helper Script

To view the script used for the restart helper, view this link to the DevSpace source code.

Custom Restart Helper Script

To provide a custom script instead of using the default restart helper in DevSpace, use the path option to point to a script:

devspace.yaml

dev:
  app:
    imageSelector: ghcr.io/org/project/image
    restartHelper:
      inject: true
      path: ./my-custom-script.sh

In the example above, DevSpace would inject the script you provide into the dev container instead of using the default script.

Config Reference

restartHelper required

RestartHelper holds restart helper specific configuration. The restart helper is used to delay starting of the container and restarting it and is injected via an annotation in the replaced pod.

path required string

Path defines the path to the restart helper that might be used if certain config options are enabled

inject required boolean false

Inject signals DevSpace to inject the restart helper