# How to Use Single Pass Mode with Cron for Scheduled Synchronization in docker-icloudpd > Learn to schedule iCloud backups with docker-icloudpd using single pass mode and cron. Configure icloudpd.conf for efficient, single-cycle synchronizations and exits. - Repository: [boredazfcuk/docker-icloudpd](https://github.com/boredazfcuk/docker-icloudpd) - Tags: how-to-guide - Published: 2026-02-26 --- **Enable `single_pass=true` in [`/config/icloudpd.conf`](https://github.com/boredazfcuk/docker-icloudpd/blob/main//config/icloudpd.conf), set the Docker restart policy to `no`, and invoke the container via host cron to run one synchronization cycle and exit.** The `boredazfcuk/docker-icloudpd` container runs continuously by default, polling for new iCloud photos at configured intervals. By activating **single pass mode with cron for scheduled synchronization**, you transform the container into an ephemeral task that performs one sync and terminates, allowing precise control over execution timing via the host's cron daemon. ## Understanding Single Pass Mode in docker-icloudpd In standard operation, the container daemonizes indefinitely, sleeping between downloads according to the `download_interval` setting. Single pass mode disables this persistence, making the container suitable for external schedulers. ### Core Implementation in sync-icloud.sh According to the source code in [`sync-icloud.sh`](https://github.com/boredazfcuk/docker-icloudpd/blob/main/sync-icloud.sh) (lines 100-108), the script evaluates the `single_pass` configuration variable during initialization. When set to `true`, the script assigns `skip_check=true`, which bypasses the periodic download-check loop and allows the process to terminate after completing the initial synchronization cycle. ## Configuring Single Pass Mode Setting up single pass mode requires two distinct configuration changes: one internal to the container's configuration and one in the container runtime parameters. ### Step 1 – Enable single_pass in icloudpd.conf Set the `single_pass` variable to `true` in your [`/config/icloudpd.conf`](https://github.com/boredazfcuk/docker-icloudpd/blob/main//config/icloudpd.conf) file. When this flag is active, the `download_interval` setting becomes irrelevant because the container exits immediately after the first sync completes. ```ini # /config/icloudpd.conf single_pass=true # Exit after one synchronisation download_interval=60 # Ignored when single_pass is enabled apple_id=user@example.com ``` ### Step 2 – Set Docker Restart Policy to "no" As documented in [`CONFIGURATION.md`](https://github.com/boredazfcuk/docker-icloudpd/blob/main/CONFIGURATION.md) (lines 106-107), you must override the default restart behavior. The [`docker-compose/docker-compose.example.yml`](https://github.com/boredazfcuk/docker-icloudpd/blob/main/docker-compose/docker-compose.example.yml) (lines 30-31) specifies `restart: always` by default, which must be changed to `"no"` for single pass usage. Without this change, Docker immediately restarts the container upon exit, potentially flooding Apple's authentication servers with requests. ```yaml # docker-compose.yml services: icloudpd: image: boredazfcuk/icloudpd restart: "no" # Required for single-pass mode environment: - TZ=Europe/London volumes: - icloudpd_config:/config - ./photos:/home/user/iCloud/ ``` ## Scheduling with Cron With the container configured to exit after a single run, use the host system's cron daemon to trigger synchronizations at specific times. ### Docker Run Method Use `docker run --rm` in your crontab to create an ephemeral container that is automatically removed after exit. Explicitly include `--restart=no` to ensure Docker does not respawn the container. ```cron 30 2 * * * /usr/bin/docker run --rm \ --name icloudpd_sync \ --restart=no \ -v icloudpd_config:/config \ -v /srv/photos/iCloud:/home/user/iCloud \ -e TZ=Europe/London \ boredazfcuk/icloudpd ``` ### Docker Compose Alternative If you manage the container with Docker Compose, use the `run` subcommand with the `--rm` flag. This executes a one-off container that inherits the `restart: "no"` setting from your compose file. ```cron 0 */6 * * * cd /opt/icloudpd && \ /usr/bin/docker compose run --rm --no-deps icloudpd ``` The `--no-deps` flag ensures only the icloudpd service runs without spawning dependent containers, while `--rm` cleans up the container after the single synchronization completes. ## Summary - Set `single_pass=true` in [`/config/icloudpd.conf`](https://github.com/boredazfcuk/docker-icloudpd/blob/main//config/icloudpd.conf) to disable the continuous execution loop in [`sync-icloud.sh`](https://github.com/boredazfcuk/docker-icloudpd/blob/main/sync-icloud.sh) - Configure Docker with `restart: "no"` to prevent automatic container respawning after single-pass exit - Use host cron with `docker run --rm` or `docker compose run --rm` to schedule ephemeral synchronization jobs - This architecture prevents resource waste and avoids excessive authentication requests to Apple's servers ## Frequently Asked Questions ### What happens if I don't set the Docker restart policy to "no"? If the restart policy remains set to `always` or `unless-stopped`, Docker immediately restarts the container when single pass mode exits. This creates a rapid restart loop that continuously authenticates with Apple's servers, potentially triggering rate limits or account restrictions as noted in the project documentation. ### Does single_pass mode ignore the download_interval setting? Yes. When `single_pass=true` is configured, the `download_interval` variable is ignored because [`sync-icloud.sh`](https://github.com/boredazfcuk/docker-icloudpd/blob/main/sync-icloud.sh) sets `skip_check=true` and exits after the first synchronization cycle rather than entering the sleep loop defined for continuous operation. ### Can I use single pass mode with Kubernetes CronJobs? Yes. Single pass mode is ideal for Kubernetes CronJobs. Configure your Job template with `restartPolicy: Never` (equivalent to Docker's `no`) and mount a configuration file with `single_pass=true`. The container runs once per scheduled Job execution and exits cleanly without lingering pods. ### Where does the container check the single_pass configuration? The container reads the `single_pass` variable from [`/config/icloudpd.conf`](https://github.com/boredazfcuk/docker-icloudpd/blob/main//config/icloudpd.conf) during the initialization phase. This value is processed in [`sync-icloud.sh`](https://github.com/boredazfcuk/docker-icloudpd/blob/main/sync-icloud.sh) between lines 100-108, where it determines whether to set the `skip_check` internal flag that controls the main execution loop's persistence.