Where is a log file with logs from a container? - docker

Question

I am running several containers using docker-compose. I can see application logs with command docker-compose logs. However I would like to access raw log file to send it somewhere for example? Where is it located? I guess it's separate log per each container (inside container?) but where I can find it?

Answer 1

A container's logs can be found in :
/var/lib/docker/containers/<container id>/<container id>-json.log
(if you use the default log format which is json)

Answer 2

You can docker inspect each container to see where their logs are:
docker inspect --format='{{.LogPath}}' $INSTANCE_ID
And, in case you were trying to figure out where the logs were to manage their collective size, or adjust parameters of the logging itself you will find the following relevant.
Fixing the amount of space reserved for the logs
This is taken from Request for the ability to clear log history (issue 1083)):
Docker 1.8 and docker-compose 1.4 there is already exists a method to limit log size using docker compose log driver and log-opt max-size:
mycontainer:
...
log_driver: "json-file"
log_opt:
# limit logs to 2MB (20 rotations of 100K each)
max-size: "100k"
max-file: "20"
In docker compose files of version '2' , the syntax changed a bit:
version: '2'
...
mycontainer:
...
logging:
#limit logs to 200MB (4rotations of 50M each)
driver: "json-file"
options:
max-size: "50m"
max-file: "4"
(note that in both syntaxes, the numbers are expressed as strings, in quotes)
Possible issue with docker-compose logs not terminating
issue 1866: command logs doesn't exit if the container is already stopped

Answer 3

To see how much space each container's log is taking up, use this:
docker ps -qa | xargs docker inspect --format='{{.LogPath}}' | xargs ls -hl
(you might need a sudo before ls).

Answer 4

docker inspect <containername> | grep log

Answer 5

On Windows, the default location is: C:\ProgramData\Docker\containers\<container-id>-json.log.

Answer 6

Here is the location for
Windows 10 + WSL 2 (Ubuntu 20.04), Docker version 20.10.2, build 2291f61
Lets say
DOCKER_ARTIFACTS == \\wsl$\docker-desktop-data\version-pack-data\community\docker
Location of container logs can be found in
DOCKER_ARTIFACTS\containers\[Your_container_ID]\[Your_container_ID]-json.log
Here is an example

Answer 7

To directly view the logfile in less, I use:
docker inspect $1 | grep 'LogPath' | sed -n "s/^.*\(\/var.*\)\",$/\1/p" | xargs sudo less
run as ./viewLogs.sh CONTAINERNAME

Answer 8

As of 8/22/2018, the logs can be found in :
/data/docker/containers/<container id>/<container id>-json.log

Answer 9

To see the size of logs per container, you can use this bash command :
for cont_id in $(docker ps -aq); do cont_name=$(docker ps | grep $cont_id | awk '{ print $NF }') && cont_size=$(docker inspect --format='{{.LogPath}}' $cont_id | xargs sudo ls -hl | awk '{ print $5 }') && echo "$cont_name ($cont_id): $cont_size"; done
Example output:
container_name (6eed984b29da): 13M
elegant_albattani (acd8f73aa31e): 2.3G