How to tail a docker log from the current position in the log without seeing the whole file or waiting for it to traverse the whole file

Question

If you use the Coreutils tail command in Linux, you have a -f option that lets you follow a log file from the log's current position (it does not go to the very beginning of the file and display everything).

Is this functionality available in docker logs without waiting for it to traverse the whole log?

I have tried:

docker logs --since 1m somecontainer

and

docker logs -f --since 1m somecontainer

It appears that it actually traverses the entire log file (which can take a long time) and then starts echoing to the screen once it reaches the time frame you specify.

Is there a way to start tailing from the current point without waiting? Is my best option to always log out to some external file and tail that with the Coreutils tail command?

Answer 1

Please read docker logs --help for help. Try below, starting from the last 10 lines. More details here.

docker logs -f --tail 10 container_name

Answer 2

Alternatively, we can check the log by time (eg. since last 2mins) as:

docker logs --since=2m <container_id> // since last 2 minutes
docker logs --since=1h <container_id> // since last 1 hour

Answer 3

use the --tail switch:

>  docker logs -f <container name> --tail 10

this will show the log starting from the last 10 lines onwards