Unknown child (SOME_ID)

[mikevandiepen]

Description

My php:8.1-fpm container throws these logs and asks me to report it.

PHP Version

8.1

Operating System

php:8.1-fpm docker container.

[cmb69]

See #9792 (comment), and please provide that feedback.

[bukka]

We have got actually quite a few reports like this. Unfortunately we often don't get enough feedback to properly investigate. It usually happens when the child crashes and somehow its pid is no longer found in children list. It's something that should not be happening but there is probably some bug allowing this to happen. If we had a reliable way to recreate, we could fix it. If you could provide more details about your application, used fpm config (if modified), that would be awesome!

I will try to play with some situations where child crashes and see if I'm able to get anywhere in the meantime.

[bukka]

I have created an issue #10315 and PR #10319 that fixes it. This happened most likely due to some orphan process that got FPM master as a new parent because the master is an init process (PID 1) - that's how it runs in Docker. The fix replaces the ALERT with DEBUG message for this case because it is really not a problem or something that can be changed. Please update this issue if you think that your issue is different.

[mikevandiepen]

please provide that feedback.

Sorry for the late response, what do you need? I haven't changed much in the php configuration, just added some (5) extensions in the dockerfile.

ARG version

FROM php:${version}-fpm

# Installing extensions used for debugging and testing.
RUN pecl install -o -f xdebug \
    && docker-php-ext-enable xdebug

# Installing the database driver for this service.
RUN docker-php-ext-install pdo_mysql \
      && docker-php-ext-enable pdo_mysql

# Installing cache for sessions & caching.
RUN pecl install -o -f redis \
    && docker-php-ext-enable redis

# Installing pcntl for horizon.
RUN docker-php-ext-install pcntl \
    && docker-php-ext-enable pcntl

# Installing zip extensions.
RUN apt-get update \
    && apt-get install -y libzip-dev \
    && docker-php-ext-install zip \
    && docker-php-ext-enable zip

COPY --from=composer /usr/bin/composer /usr/bin/composer

# xDebug socket
zend_extension=xdebug.so

# xDebug configuration.
xdebug.mode=debug
xdebug.idekey=PHPSTORM
xdebug.client_host=host.docker.internal
xdebug.client_port=9003
xdebug.start_upon_error=yes
xdebug.log_level=0

services:
  php:
    build:
      context: ./docker/php
      args:
        version: ${DOCKER_PHP_VERSION}
    container_name: ${DOCKER_CONTAINER_NAME}.php
    hostname: backend.${DOCKER_CONTAINER_NAME}.php
    working_dir: /var/www/html/
    platform: linux/x86_64
    tty: true
    restart: unless-stopped
    environment:
      PHP_DISPLAY_ERRORS: ${PHP_DISPLAY_ERRORS}
      PHP_MEMORY_LIMIT: ${PHP_MEMORY_LIMIT}
      PHP_MAX_EXECUTION_TIME: ${PHP_MAX_EXECUTION_TIME}
      PHP_IDE_CONFIG: serverName=${DOCKER_CONTAINER_NAME}
    volumes:
      - .:/var/www/html/
      - ./docker/php/xdebug.ini:/usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
    depends_on:
      - database
      - cache
    networks:
      - backend

[bukka]

As I mentioned in the linked issue, this is not really an issue if you run it in Docker as it runs as init proces (pid = 1). I just pushed a fix 4199b72 that re-classify this alert to debug messages so you should no longer see that in the logs once you update to the future 8.1.16.

[bukka]

Basically there is like some other process created. My primary candidate was horizon as it uses pcntl but then I noticed it's just catching signals so it should not cause this so not sure but it can be many things. Anyway as I said it is not really an issue.