The impact of the Docker clean command

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AI-generated summary

Truest encountered a Discourse bootstrap failure during an update, traced to Nginx and Unicorn instability, likely due to insufficient disk space. After rebooting and rebuilding, they were prompted to clean Docker images/containers via a system prune option — which they accepted — and Discourse subsequently worked. They questioned whether this cleanup (equivalent to docker system prune -a) could damage Discourse files or packages, given the large space reclaimed. pfaffman reassured them that the issue was almost certainly disk space exhaustion, and that the prune command is safe and equivalent to the manual Docker command — no harm to Discourse. Truest followed up, confirming their concern stemmed from distrust of the large space freed (unlike ./launcher apt-get auto-clean), but accepted the reassurance that Discourse remains unaffected.

1 
assets
' failed with return #<Process::Status: pid 1222 exit 1>
Location of failure: /usr/local/lib/ruby/gems/3.3.0/gems/pups-1.2.1/lib/pups/exec_command.rb:132
`spawn'
exec failed with the params {"cd"=>"$home", "tag"=>"precompile", "hook"=>"assets_precompile", "cmd"=>["su discourse -c 'SKIP_EMBER_CLI_COMPILE=1 bundle exec rake themes
assets
'"]}
bootstrap failed with exit code 1
** FAILED TO BOOTSTRAP ** please scroll up and look for earlier error messages, there may be more than one.
./discourse-doctor may help diagnose the problem.

I tried this update and ran into this error.

I immediately looked in the logs and found that Nginx was not starting properly and Unicorn was restarting frequently. So I completely restarted the Ubuntu server and tried to rebuild Discourse once again.

I got the following message: “Would you like to attempt to recover space by cleaning docker images and containers in the system? (y/N)”

I pressed Y.

After the command finished working, I rebuilt Discourse again.

It’s working fine now.

I have a few questions.

  1. if Nginx is not working properly or Unicorn is restarting frequently, what is the problem in general?
  2. I noticed that the action of the command “Would you like to attempt to recover space by cleaning docker images and containers in the system?” (y/N) → “docker system prune -a” is similar to the action of the command “docker system prune -a”. Is there something about running this command that breaks packages or files related to Discourse?
    I have freed up quite a bit of disk space since running this command.
    Speaking of freeing up quite a bit, it’s been nagging at me like an obsession…
    I’ve looked around the site a bit, and there doesn’t seem to be anything wrong, but it’s keeping me awake at night.
2

My guess is that your problem was that you were out of disk space, but the error is above where you started copying the logs.

It’s the same as running the docker prune command except you don’t have to know about the docker prune command.

I think it’s safe to sleep.

3

So, since this frees up quite a bit of capacity, can i just assume that Discourse is unaffected?

Why i Asked Again
Cleaning up “./launcher
apt-get auto-clean
apt-get auto-remove” command didn’t do much, but the prune command freed up a lot of space, which I didn’t trust, so I asked.:slightly_smiling_face: