Docker Redis备份示例中--rm与--volumes-from参数作用咨询

Hey there! Let's break down those two Docker parameters in your backup command—they're total lifesavers for one-off tasks like this.

1. What does --rm do? #

The --rm flag tells Docker to automatically delete the container the second it finishes running and exits.

In your example, you're using a debian container just to run a single cp command. Once that copy is done, the container has no more purpose. Without --rm, that container would linger in an "exited" state (you'd spot it if you ran docker ps -a). Over time, these leftover containers can clutter your system and eat up unnecessary disk space.

Using --rm is perfect for short-lived, throwaway containers like this backup helper. It saves you from having to manually run docker rm <container-id> later to clean up the mess.

2. What does --volumes-from do? #

The --volumes-from flag lets your new container mount all the volumes that are attached to another existing container.

In your command, you're targeting the myredis container. That Redis container almost definitely has a volume mounted at /data (where Redis stores its dump.rdb database file). By adding --volumes-from myredis, your debian container gets full access to that same /data directory—so it can read the dump.rdb file and copy it to your local backup folder (connected via -v $(pwd)/backup:/backup).

This is a smart way to share data between containers without having to explicitly name or create volumes yourself. It's especially useful for tasks like backups, where you need temporary access to another container's data without touching or modifying the original container at all.

Quick recap of your command #

Your backup workflow is clean and efficient:

• Use a lightweight debian container to handle the file copy (no need to install tools on your host or Redis container)
• --volumes-from myredis gives the container access to Redis's data volume
• -v $(pwd)/backup:/backup links your local folder to the container for the backup output
• --rm ensures the container vanishes right after the backup completes

内容的提问来源于stack exchange，提问作者MikiBelavista