Building docker images inside instance and /data/docker

Questions / Help
1

Hi,

I’m running a Fly instance that is building docker images, as part of my setup described in Is fly planning instances larger than 8 cores? - #3 by leighmcculloch.

I keep running out of disk space and need to keep deleting images. I attempted to mount a persistent volume that was larger, but it appears the /data/docker directory where docker is writing images to is already a mount of some kind with a small fixed size.

Does Fly mount a persistent volume already for /data/docker? Is there anyway to override it and set a larger size?

Thanks!
Leigh

2

Your image might already have that directory in it. What does your fly.toml look like?

This is the app I use for my remote Docker daemon: GitHub - fly-apps/docker-daemon: A Docker daemon to run in Fly and access via a WireGuard peer.

In fly.toml, you’ll see that it mounts the volume to /data, and then the Docker config specifies /data/docker:

There’s a script in there that creates the /data/docker directory if necessary: docker-daemon/docker at main · fly-apps/docker-daemon · GitHub

3

Thanks, that helped. I realized I was configuring the /data/docker directory myself too, I’d just forgotten about that. And mounting at /data works a charm.

Another question: I had planned to have two mounts, but looks like only one persistent volume is supported now. Is that right?

4

Yes, that’s right. We currently can’t mount more than one volume per VM.

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