Docker failed to start after installation in centos7

  docker, question

[root@localhost Desktop]# rpm -qi docker
Name : docker
Version : 1.5
Release : 5.el6
Architecture: x86_64
Install Date: Sat 02 May 2015 12:12:36 PM CST
Group : User Interface/X
Size : 37603
License : GPL+
Signature : RSA/SHA256, Fri 02 Jul 2010 05:28:52 AM CST, Key ID 3b49df2a0608b895
Source RPM : docker-1.5-5.el6.src.rpm
Build Date : Fri 02 Jul 2010 02:32:06 AM CST
Build Host : x86-05.phx2.fedoraproject.org
Relocations : (not relocatable)
Packager : Fedora Project
Vendor : Fedora Project
URL :http://icculus.org/openbox/2/docker/
Summary : KDE and GNOME2 system tray replacement docking application
Description :
Docker is a docking application (WindowMaker dock app) which acts as a system
tray for KDE and GNOME2. It can be used to replace the panel in either
environment, allowing you to have a system tray without running the KDE/GNOME
panel or environment.

[root@localhost Desktop]# systemctl start docker.service
Failed to issue method call: Unit docker.service failed to load: No such file or directory.

For example, the rgba value of each point is taken as an average value, and according to this strategy, how each pixel point is calculated to obtain the merged pixel point data is obtained. Get a merged iamgeData,
Then get it into the merged canvas through the putImage method.