I'm trying to understand what kind of important data can be lost when I run the command `docker system prune -a`. It says it will remove all stopped containers, networks not used by at least one container, images without associated containers, and the build cache. Since Docker containers are ephemeral, I get that data is lost when they stop if it isn't saved in volumes. For networks, I assume they can be recreated when needed. Images are immutable, so I don't think they hold irrecoverable data. The build cache seems minor as well. I can't really see a scenario where this leads to significant data loss unless I have to pull images again. Can anyone clarify this for me?
1 Answer
If you have custom networks created manually (not defined in Docker Compose), you'll lose those if you prune them without knowing. Also, if you only occasionally use locally built images and haven’t pushed them to a registry, you might face a hassle when needing to rebuild them later. Some folks use unusual methods like `docker save`, making certain images tricky to re-create if they get pruned. So, while pruning is generally fine, it can come with some hidden complications. Just be cautious if you're in the middle of debugging or if you lack solid documentation of your setups!
Thanks! This explanation really clears things up for me.