Docker look at the log of an exited container
DockerDocker Problem Overview
Is there any way I can see the log of a container that has exited?
I can get the container id of the exited container using docker ps -a but I want to know what happened when it was running.
Docker Solutions
Solution 1 - Docker
Use docker logs. It also works for stopped containers and captures the entire STDOUT and STDERR streams of the container's main process:
$ docker run -d --name test debian echo "Hello World"
02a279c37d5533ecde76976d7f9d1ca986b5e3ec03fac31a38e3dbed5ea65def
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
49daa9d41a24 debian "echo test" 2 minutes ago Exited (0) 2 minutes ago test
$ docker logs -t test
2016-04-16T15:47:58.988748693Z Hello World
Solution 2 - Docker
docker logs --tail=50 <container id> for the last fifty lines - useful when your container has been running for a long time.
Solution 3 - Docker
You can use below command to copy logs even from an exited container :
> docker cp container_name:path_of_file_in_container destination_path_locally
Eg:
docker cp sample_container:/tmp/report /root/mylog
Solution 4 - Docker
To directly view the logfile of an exited container in less, scrolled to the end of the file, I use:
docker inspect $1 | grep 'LogPath' | sed -n "s/^.*\(\/var.*\)\",$/\1/p" | xargs sudo less +G
run as ./viewLogs.sh CONTAINERNAME
This method has the benefit over docker logs based approaches, that the file is directly opened, instead of streamed.
sudo is necessary, as the LogPath/File usually is under root-owned
Solution 5 - Docker
@icyerasor comment above actually helped me solve the issue. In my particular situation the container that has stopped running had no container name only container id.
Steps that found the logs also listed in this post
- Find the stopped container via
docker ps - a - grab the container id of the failed container
- Substitute it in this command
cat /var/lib/docker/containers/<container id>/<container id>-json.log