Where is the Docker daemon log?

Question

Where is the Docker daemon log? Oddly cannot find an answer to this via man, StackOverflow or Docker Docs. Note I am not asking for the docker container STDOUT, but the daemon log for troubleshooting communications between the client and container via daemon / proxy.

Answer 1

Using CentOS7, logs are available using the command journalctl -u docker. Answering distinctly, because @sabin's answer might be accurate for older versions of CentOS but was not true for me.

systemd has its own logging system called the journal. The logs for the docker daemon can be viewed using journalctl -u docker

Ref: https://docs.docker.com/engine/admin/configuring/

Answer 2

If your OS is using systemd then you can view docker daemon log with:

sudo journalctl -fu docker.service

Answer 3

For Mac with Docker Toolbox, ssh into the VM first with docker-machine ssh %VM-NAME% and then check /var/log/docker.log

Answer 4

In my environment(docker for mac 17.07), there is no log file at ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/log/d‌​ocker.log

Instead I can find log file as below.

1. Enter into VM.

   $ screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty

2. Check log file

   / # tail -f /var/log/docker.log