Description:
when starting docker container with journald log-driver, I found container logs were successfully stored into journald, but could not be read out through docker daemon
It maybe caused by a pkgconfig bug of upstream (https://github.com/docker/docker/issues/20497)
However, as the upstream had fixed this problem (https://github.com/docker/docker/pull/20617), I think we can update the docker package now.

Additional info:
pacman -Qi docker
Name : docker
Version : 1:1.10.2-2
Description : Pack, ship and run any application as a lightweight container
Architecture : x86_64
URL : https://www.docker.com/
Licenses : Apache
Groups : None
Provides : None
Depends On : bridge-utils iproute2 device-mapper sqlite systemd
Optional Deps : btrfs-progs: btrfs backend support
lxc: lxc backend support
Required By : docker-compose
Optional For : None
Conflicts With : None
Replaces : None
Installed Size : 40.56 MiB
Packager : Sébastien Luttringer <seblu@seblu.net>
Build Date : Thu 25 Feb 2016 04:30:20 PM CST
Install Date : Mon 07 Mar 2016 04:02:49 PM CST
Install Reason : Explicitly installed
Install Script : Yes
Validated By : Signature



Steps to reproduce:
1. run docker images with journald log-driver
docker run --log-driver journald hello-world

2. find the <CONTAINER ID> and <NAME>
docker ps --all |head

3. check the logs, FAIL!!!
docker logs <CONTAINER ID>

Error running logs job: configured logging reader does not support reading

but journalctl works
journalctl CONTAINER_NAME=<NAME>

-- Logs begin at Mon 2015-10-19 11:47:33 CST, end at Tue 2016-03-08 09:56:39 CST. --
Mar 08 09:56:39 A1 docker[11614]:
Mar 08 09:56:39 A1 docker[11614]: Hello from Docker.
Mar 08 09:56:39 A1 docker[11614]: This message shows that your installation appears to be working correctly.
Mar 08 09:56:39 A1 docker[11614]:
Mar 08 09:56:39 A1 docker[11614]: To generate this message, Docker took the following steps:
Mar 08 09:56:39 A1 docker[11614]: 1. The Docker client contacted the Docker daemon.
Mar 08 09:56:39 A1 docker[11614]: 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
Mar 08 09:56:39 A1 docker[11614]: 3. The Docker daemon created a new container from that image which runs the
Mar 08 09:56:39 A1 docker[11614]: executable that produces the output you are currently reading.
Mar 08 09:56:39 A1 docker[11614]: 4. The Docker daemon streamed that output to the Docker client, which sent it
Mar 08 09:56:39 A1 docker[11614]: to your terminal.
Mar 08 09:56:39 A1 docker[11614]:
Mar 08 09:56:39 A1 docker[11614]: To try something more ambitious, you can run an Ubuntu container with:
Mar 08 09:56:39 A1 docker[11614]: $ docker run -it ubuntu bash
Mar 08 09:56:39 A1 docker[11614]:
Mar 08 09:56:39 A1 docker[11614]: Share images, automate workflows, and more with a free Docker Hub account:
Mar 08 09:56:39 A1 docker[11614]: https://hub.docker.com
Mar 08 09:56:39 A1 docker[11614]:
Mar 08 09:56:39 A1 docker[11614]: For more examples and ideas, visit:
Mar 08 09:56:39 A1 docker[11614]: https://docs.docker.com/userguide/
Mar 08 09:56:39 A1 docker[11614]: