DevOps

1669 readers

34 users here now

DevOps integrates and automates the work of software development (Dev) and IT operations (Ops) as a means for improving and shortening the systems development life cycle.

Rules:

Posts must be relevant to DevOps
No NSFW content
No hate speech, bigotry, etc
Try to keep discussions on topic
No spam of tools/companies/advertisements
It’s OK to post your own stuff part of the time, but the primary use of the community should not be promotional content.

Icon base by Lorc under CC BY 3.0 with modifications to add a gradient

founded 1 year ago

MODERATORS

[email protected]

What's the biggest docker footgun you've experienced? (programming.dev)

submitted 1 year ago by [email protected] to c/[email protected]

22 comments fedilink hide all child comments

I'll start:

When I was first learning to use Docker, I didn't realize that most tutorials that include a database don't configure the database to persist. Imagine my surprise when I couldn't figure out why the database kept getting wiped!

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (3 children)

The biggest footgun I encounter every time I set up a raspberry pi or other linux host for a side project is forgetting that Docker doesn't do log rotation for containers' logs by default, which results in the service going down and seeing a sweat inducing ENOSPC error when you ssh in to check it out.

You can configure this by creating /etc/docker/daemon.json and either setting up log rotation with log-opts or using the local logging driver (it defaults to json) if you're not shipping container logs anywhere and just read the logs locally. The local driver compresses the logs and automatically does log rotation:

{
  "log-driver": "local",
  "log-opts": {
     "max-size": "10m",
     "max-file": "3"
  }
}

[–] [email protected] 3 points 1 year ago (1 children)

I prefer this method:

{
  "log-driver": "syslog",
  "log-opts": {
    "tag": "docker.{{.Name}}"
  }
}

This way container logs are forwarded to /var/log/syslog, which already contains all other services logs, and has sane rotation rules by default (and it allows rsyslog to manage log forwarding/shipping if needed).

[–] [email protected] 2 points 1 year ago

Thanks, good to know! I had no idea about the tags. Looks like there's a lot more variables available.

I just reread the docs on the log drivers - they mentioned that as of docker 20.x local logs now work with all drivers as it buffers the logs locally as well. I think this is probably why I hadn't explored the other drivers before - couldn't use docker-compose logs.

load more comments (1 replies)