Docker is great, slow Rails apps is not
It’s apparently a known issue to have slow Rails apps under Docker in development due to folder sharing in VirtualBox.
There are many suggestions as to how to fix this, so I tried a few.
- Sharing Host Volumes with Docker Containers is a good overview of multiple things to try by Oliver Günther.
- I started with docker-osx-dev but received rsync errors after running it for a few minutes.
- Switched to VMWare Fusion and that didn’t help so maybe it’s not VirtualBox file sharing.
- Tried docker-rysnc under Fusion but it gave me:
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at /BuildRoot/Library/Caches/com.apple.xbs/Sources/rsync/rsync-47/rsync/io.c(453) [sender=2.6.9]
error: exit status 12
Watching for file changes ...
Maybe this magic bullet shit won’t work, let’s try using an image as part of compose so that we’re more explicit about this syncing process.
- Looks like docker-unison works to sync files and it syncs them quickly but the application still takes 20 seconds to load a simple page.
- dinghy created a VM as a wrapper to docker-machine and no luck with that too.
Other NFS scripting options:
- Boot2docker: Using nfs instead of vboxsf to mount /Users
- How Blackfire leverages Docker under the File Sharing section
- boot2docker-nfs.rb is a simple gist working with VirtualBox
Since I have Fusion installed though, this seems like a lot of work to just get a basic Rails app to run.
My solution:
- Use Docker for everything not Rails or Guard. Postgres and workers seem fast enough.
- Run Rails locally with your standard
gem install bundler; bundle. - Leave the app running in Docker Compose if I need to check out anything in Linux but avoid it at all costs.
I’ve got too much real work to do.