title: Docker daemon recently takes over 1 min to start - why?
body: <h1>Problem</h1>
  
  <p>The Docker systemd daemon takes over a minute to start on my Fedora 27 laptop. This was not always the case – I first noticed the slowdown about 1-2 months ago. How can I speed up the Docker daemon start time?</p>
  
  <h1>Analysis</h1>
  
  <p>I looked at the logs for the Docker engine, but it wasn't helpful. There's a large window where it doesn't seem like anything is happening.</p>
  
  <pre><code># journalctl -fu docker
  Jan 23 15:10:05 fossbook.justinwflory.com systemd[1]: Starting Docker Application Container Engine...
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.830665755-05:00" level=warning msg="devmapper: Usage of loopback devices is strongly discouraged for production use. Please use `--storage-opt dm.thinpooldev` or use `man docker` to refer to dm.thinpooldev section."
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.869370589-05:00" level=warning msg="devmapper: Base device already exists and has filesystem xfs on it. User specified filesystem  will be ignored."
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.885762067-05:00" level=info msg="[graphdriver] using prior storage driver: devicemapper"
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.893578695-05:00" level=info msg="Graph migration to content-addressability took 0.00 seconds"
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.894872003-05:00" level=warning msg="Your kernel does not support cgroup rt period"
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.895330760-05:00" level=warning msg="Your kernel does not support cgroup rt runtime"
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.896277400-05:00" level=info msg="Loading containers: start."
  Jan 23 15:11:35 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:35.917175821-05:00" level=info msg="Firewalld running: true"
  Jan 23 15:11:36 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:36.695388606-05:00" level=info msg="Default bridge (docker0) is assigned with an IP address 172.17.0.0/16. Daemon option --bip can be used to set a preferred IP address"
  Jan 23 15:11:36 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:36.961050250-05:00" level=info msg="Loading containers: done."
  Jan 23 15:11:36 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:36.975477466-05:00" level=warning msg="failed to retrieve docker-init version: unknown output format: tini version 0.16.1\n"
  Jan 23 15:11:36 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:36.976280875-05:00" level=info msg="Daemon has completed initialization"
  Jan 23 15:11:36 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:36.976323468-05:00" level=info msg="Docker daemon" commit=caba767-unsupported graphdriver=devicemapper version=1.13.1
  Jan 23 15:11:36 fossbook.justinwflory.com dockerd-current[20839]: time="2018-01-23T15:11:36.993394464-05:00" level=info msg="API listen on /var/run/docker.sock"
  Jan 23 15:11:36 fossbook.justinwflory.com systemd[1]: Started Docker Application Container Engine.
  </code></pre>
  
  <p>I'm not aware of other helpful information to help me debug this. I know past behavior was almost instantaneous – this seems like a regression or a configuration error.</p>
  
  <h1>How to debug?</h1>
  
  <p>I'm not sure how to debug this correctly because the logs are unhelpful. Is there more detailed information I can get on startup? How can I figure out what's taking so long?</p>