Running WordPress Cron the Right Way When Your Site Lives in Docker

We host a travel blog (joyofexploringtheworld.com) on a low-cost VPS with Docker Compose and Cloudflare in front. WordPress’s built-in cron was causing intermittent timeouts in our logs. Here’s how we fixed it.

The problem with WordPress cron in Docker Link to heading

WordPress cron normally “pings itself” on each page load—an HTTP POST to the site from inside the container. Behind a CDN and in Docker, that ping can time out, fail, or hit the wrong instance. We saw cURL timeouts in Datadog and unreliable scheduled tasks.

The solution: a cron sidecar Link to heading

We set DISABLE_WP_CRON and run cron from a small sidecar container that executes wp cron event run --due-now every minute. The sidecar needs the same database and Redis config as the main WordPress service, and enough PHP memory (e.g. php -d memory_limit=512M when using a custom entrypoint).

# docker-compose.yml — wp-cron sidecar service
wp-cron:
  image: wordpress:cli
  volumes_from:
    - wordpress
  entrypoint: /bin/sh
  command: >-
    -c 'while true; do php -d memory_limit=512M /usr/local/bin/wp cron event run --due-now; sleep 60; done'
  environment:
    WORDPRESS_DB_HOST: db
    WORDPRESS_DB_USER: $MYSQL_USER
    WORDPRESS_DB_PASSWORD: $MYSQL_PASSWORD
    WORDPRESS_DB_NAME: $MYSQL_DATABASE
    PHP_MEMORY_LIMIT: 512M
    WORDPRESS_CONFIG_EXTRA: |
      define('WP_REDIS_HOST', 'redis');
      define('WP_REDIS_PORT', '6379');
      define('WP_CACHE', true);
      define('DISABLE_WP_CRON', true);
      define('WP_MEMORY_LIMIT', '512M');
  depends_on:
    - wordpress
  restart: always

What you can do Link to heading

Set DISABLE_WP_CRON in wp-config.php or via WORDPRESS_CONFIG_EXTRA.
Add a cron sidecar to your Docker Compose that runs wp cron event run --due-now every 60 seconds.
Give the sidecar the same WORDPRESS_DB_* and Redis config as the main service.
Ensure sufficient PHP memory for the CLI container.

In containerised or CDN setups, scheduled tasks are more reliable when run by a dedicated process instead of page loads.

The full docker-compose.yml is in the companion repo.

Built for a travel blog on a budget. This stack powers Joy of Exploring the World — curated travel itineraries, restaurant reviews, and destination guides. If you're planning your next trip, come explore with us.

All config files from this post are in the companion GitHub repo.