Apache process shutting down on SIGWINCH

[merlinscholz]

Hi, when using the docker:stable container (and all other non-fpm labels), viewing the Docker logs on some systems (for example on Synology DiskStations) causes a SIGWINCH to be send to the Apache2 process. This causes it to shutdown gracefully. If auto-restarting is enabled, this process repeats as long as the according log window is left open.

A workaround is to only use docker command over ssh on those systems.

[J0WI]

I suspect this is an issue with Docker on Synology and not caused by the Nextcloud image.

[merlinscholz]

I was mainly wondering if terminating on SIGWINCH is a function that should be enabled in the Nextcloud image, since I do not see any reason in which a SIGWINCH should cause Nextcloud to stop. Apache2 mainly implemented this feature to allow graceful shutdowns (https://bz.apache.org/bugzilla/show_bug.cgi?id=50669). Other projects have the same issue and worked around it: https://github.com/GrahamDumpleton/mod_wsgi/issues/105#issuecomment-359783948

[James-Quigley]

[mpm_prefork:notice] [pid 1] AH00170: caught SIGWINCH, shutting down gracefully

Also getting a SIGWINCH error running the apache container

[James-Quigley]

Also appears to be an issue when running within kubernetes if the system is using containerd. And apache uses SIGWINCH as a graceful termination signal (https://httpd.apache.org/docs/2.4/en/stopping.html#gracefulstop)

[J0WI]

See also https://github.com/docker-library/php/issues/877 and https://github.com/docker-library/php/issues/907

[AndrStnz]

Do we have a workaround for this? We see this behaviour with k8s and containerd too. This is kinda a show stopper :(

[J0WI]

Maybe https://github.com/docker-library/php/issues/64#issuecomment-71124775= has a workaround for you. We consume apache from https://github.com/docker-library/php.

[bambam247]

Same behaviour here k8s and containerd. showstopper.

[SNThrailkill]

Also having this issue with K8s and using the helm chart

[grglzrv]

the same here, you need to use nextcloud:fpm (with fpm tag) + nginx enabled

[robproject]

same error with bare metal installation and opening nextcloud talk app

[golgotow]

still no fix ?

[jsalatiel]

Also broken here on k8s + crio.

[umarmughal824]

I am also facing that issue.

[QuinnBast]

Just wanted to comment here. I was running into this problem as well. I fixed this problem after properly setting my config.php files. When using the default docker image, the default configurations that come with don't quite work I guess, so I had to (with docker: use -v to volume mount additional configuration files into the right spot), or, with the kubernetes helm chart, I had to set the proper config settings in either nextcloud.configs or nextcloud.defaultConfigs, or nextcloud.phpConfigs. Once I had the right configuration files in place it started working.

[MannerMan]

I was able to work-around this with nextcloud on k3s without rebuilding the offical docker image by mounting a trap wrapper script that traps the SIGWINCH signal, thereby not passing it to apache.

nextcloud deployment.yml:

[...]
          spec:
            volumes:
            - name: nextcloud-trap
              configMap:
                name: nextcloud-trap
                defaultMode: 0777 # < to ensure script can be executed
            containers:
            - image: nextcloud:26
              name: nextcloud
              command: ["/bin/bash", "-c"]
              args:
              - /nextcloud_trap.sh
[...]
              volumeMounts: 
              - name: nextcloud-trap
                mountPath: /nextcloud_trap.sh
                subPath: nextcloud_trap.sh

nextcloud trap configmap:

      apiVersion: v1
      kind: ConfigMap
      metadata:
        name: nextcloud-trap
        namespace: default
      data:
        nextcloud_trap.sh: |
          trap "" SIGWINCH
          /entrypoint.sh apache2-foreground

[kolAflash]

Workaround to prevent SIGWINCH from reaching the Apache process:
setsid COMMAND
Replace "COMMAND" with the actual command.

 

Workaround keeping the process in foreground and forwarding SIGINT (ctrl-c):

setsid --wait COMMAND &
child_pid=$!
trap "kill -SIGINT $child_pid" SIGINT
wait $child_pid

 

For "setsig" see also: https://en.wikipedia.org/wiki/Process_group

[j-bolivar-lt]

Definitely there's an issue with the image/helm configuration.

This one worked for me:

flavor: apache
version: 4.5.12