A php application on docker works fine on Ubuntu 23.10 but crashes on 24.04

Question

I have the following docker configuration for Mautic (A PHP based CRM):

x-mautic-volumes:
  &mautic-volumes
  - ./mautic/config:/var/www/html/config:z
  - ./mautic/logs:/var/www/html/var/logs:z
  - ./mautic/media/files:/var/www/html/docroot/media/files:z
  - ./mautic/media/images:/var/www/html/docroot/media/images:z
  - ./mautic/themes/leeway_newsletter:/var/www/html/docroot/themes/leeway_newsletter:z
  - ./mautic/themes/leeway_responsive:/var/www/html/docroot/themes/leeway_responsive:z
  - ./session.ini:/usr/local/etc/php/conf.d/session.ini:z
  - ./cron:/opt/mautic/cron:z
  - mautic-docroot:/var/www/html/docroot:z
  - mautic-vendor:/var/www/html/vendor:z

services:
  nginx:
    image: nginx
    volumes:
      - ./nginx.conf:/etc/nginx/conf.d/default.conf
      - mautic-docroot:/var/www/html/docroot:z
      - ./mautic/media/files:/var/www/html/docroot/media/files:z
      - ./mautic/media/images:/var/www/html/docroot/media/images:z
      - ./.well-known:/var/www/html/docroot/.well-known
    depends_on:
      - web
    ports:
      - "127.0.0.1:8002:80"
    networks:
      - default
    restart: always

  web:
    image: my_mautic:5.2.1
    build: .
    volumes: *mautic-volumes

    env_file:
      - .mautic_env
    healthcheck:
      test: cgi-fcgi -bind -connect 127.0.0.1:9000
      start_period: 5s
      interval: 5s
      timeout: 5s
      retries: 100
    networks:
      - default
    restart: always

  cron:
    image: my_mautic:5.2.1
    build: .
    volumes: *mautic-volumes
    environment:
      - DOCKER_MAUTIC_ROLE=mautic_cron
    env_file:
      - .mautic_env
    depends_on:
      web:
        condition: service_healthy
    networks:
      - default
    restart: always

volumes:
  mautic-docroot:
    name: mautic-5.2.1
  mautic-vendor:
    name: mautic-5.2.1-vendor

networks:
  default:
    name: ${COMPOSE_PROJECT_NAME}-docker

This application is accessed through an NginX that takes care of SSL and forwards traffic to both this docker container and a regular WordPress hosted directly on the server using php8.2-fpm.

I have my servers on Basic Premium Intel droplets (1 GB Ram, 1vCPU, 25GB disk).

The app is currently running just fine on an Ubuntu 23.10 server.

I tried to put together a new server using Ubuntu 24.04 and, using the exact same configuration, after running for about 20 minutes, the CPU usage will go to 100% and stay there until I manually kill the in-docker php-fpm process.

I tried installing docker from the official sources, re-install the whole thing from scratch to make sure I wasn’t using old volumes, explicitly limited resources for the web container but I always end up in the same place.

Any idea?

Thanks!

alexdo · Answer

Hello, @maurochojrin You can use tools like htop or iotop to identify bottlenecks: It will be useful to check if a process outside Docker is interfering with PHP-FPM. Also you can monitor which exct process is consuming the CPU and memory on the droplet. This willl give you insight which configuration you can tweak - php-fpm, nginx and etc. The high CPU usage is likely due to an issue with PHP-FPM or the Mautic app’s handling of requests: Inspect the PHP-FPM logs within the container to identify errors or repetitive processes. Look for: Too many processes being spawned (pm.max_children being exceeded). High request durations or slow script execution. Also there might be a high disk usage or slow reads/writes could cause processes to hang. Hope that this helps!

KFSys · Answer

If you issue comes from the php-fpm proccesses that are being spawned, you’ll need to tweak them a little bit. pm = dynamic pm.max_children = 10 pm.start_servers = 2 pm.min_spare_servers = 2 pm.max_spare_servers = 4 pm.max_requests = 500 Try something like the above. Now, I am also baffled about why it’s happening on Ubuntu 24.04. The only thing I can think of is that maybe there are some differences between the versions which lead to this. Resource Limits : Check and compare cgroup settings, ulimits, and file system configurations. Dependencies : Compare installed libraries and dependencies across both system.Ensure SELinux/AppArmor settings are not overly restrictive as well.

389bc128c686438f9abf61697c8039 · Answer

It seems like the issue might stem from differences in Ubuntu 24.04 affecting either PHP-FPM or Docker. I’d suggest checking the PHP-FPM error logs inside the container (/var/log/php-fpm.log or similar) to see if there are any warnings or errors pointing to the problem. Additionally, since the CPU spikes are tied to the PHP-FPM process, review your php-fpm.conf and pool.d settings—specifically pm.max_children, pm.max_requests, and pm.start_servers. Misconfigurations in these can easily lead to resource overloads. Another thing to consider is the newer kernel in Ubuntu 24.04. Sometimes, differences in kernel versions can cause unexpected behavior. If possible, try downgrading the kernel to match 23.10 and see if that resolves the issue. You should also check whether the system’s OOM (Out of Memory) killer is interfering—look at dmesg or journalctl for any signs of the kernel stepping in. Lastly, even though you’ve already limited container resources, it might help to tighten those limits further using Docker’s --cpus and --memory options in your docker-compose.yml. If none of these solutions work, you could try using a different PHP-FPM version on the 24.04 setup as a test to isolate the issue. Hope this helps! Let us know how it goes—I’d love to hear if you figure it out!

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A php application on docker works fine on Ubuntu 23.10 but crashes on 24.04

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