Install docker(CentOS7)

[root@mail ~]# yum install -y yum-utils
Loaded plugins: auto-update-debuginfo, fastestmirror, langpacks
Determining fastest mirrors
 * base: ftp.kaist.ac.kr
 * extras: ftp.kaist.ac.kr
 * updates: ftp.kaist.ac.kr
base-debuginfo                                                                                 | 2.5 kB  00:00:00  
base-debuginfo/x86_64/primary_db                                                               | 2.6 MB  00:00:04  
Package yum-utils-1.1.31-50.el7.noarch already installed and latest version
Nothing to do

[root@mail ~]# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
Loaded plugins: auto-update-debuginfo, fastestmirror, langpacks
adding repo from: https://download.docker.com/linux/centos/docker-ce.repo
grabbing file https://download.docker.com/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo

[root@mail ~]# yum install -y docker-ce
Loaded plugins: auto-update-debuginfo, fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: ftp.kaist.ac.kr
 * extras: ftp.kaist.ac.kr
 * updates: ftp.kaist.ac.kr
docker-ce-stable                                                                               | 3.5 kB  00:00:00  
docker-ce-stable-debuginfo                                                                     | 3.5 kB  00:00:00  
(1/4): docker-ce-stable/x86_64/updateinfo                                                      |   55 B  00:00:00  
(2/4): docker-ce-stable/x86_64/primary_db                                                      |  29 kB  00:00:00  
(3/4): docker-ce-stable-debuginfo/x86_64/updateinfo                                            |   55 B  00:00:00  
(4/4): docker-ce-stable-debuginfo/x86_64/primary_db                                            | 6.4 kB  00:00:00  
Resolving Dependencies
There are unfinished transactions remaining. You might consider running yum-complete-transaction, or "yum-complete-transaction --cleanup-only" and "yum history redo last", first to finish them. If those don't work you'll have to try removing/installing packages by hand (maybe package-cleanup can help).
--> Running transaction check
---> Package docker-ce.x86_64 3:18.09.7-3.el7 will be installed
--> Processing Dependency: container-selinux >= 2.9 for package: 3:docker-ce-18.09.7-3.el7.x86_64
--> Processing Dependency: containerd.io >= 1.2.2-3 for package: 3:docker-ce-18.09.7-3.el7.x86_64
--> Processing Dependency: docker-ce-cli for package: 3:docker-ce-18.09.7-3.el7.x86_64
--> Running transaction check
---> Package container-selinux.noarch 2:2.99-1.el7_6 will be installed
---> Package containerd.io.x86_64 0:1.2.6-3.3.el7 will be installed
---> Package docker-ce-cli.x86_64 1:18.09.7-3.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

======================================================================================================================
 Package                        Arch                Version                       Repository                     Size
======================================================================================================================
Installing:
 docker-ce                      x86_64              3:18.09.7-3.el7               docker-ce-stable               19 M
Installing for dependencies:
 container-selinux              noarch              2:2.99-1.el7_6                extras                         39 k
 containerd.io                  x86_64              1.2.6-3.3.el7                 docker-ce-stable               26 M
 docker-ce-cli                  x86_64              1:18.09.7-3.el7               docker-ce-stable               14 M

Transaction Summary
======================================================================================================================
Install  1 Package (+3 Dependent packages)

Total download size: 59 M
Installed size: 243 M
Downloading packages:
(1/4): container-selinux-2.99-1.el7_6.noarch.rpm                                               |  39 kB  00:00:00  
warning: /var/cache/yum/x86_64/7/docker-ce-stable/packages/docker-ce-18.09.7-3.el7.x86_64.rpm: Header V4 RSA/SHA512 Signature, key ID 621e9f35: NOKEY
Public key for docker-ce-18.09.7-3.el7.x86_64.rpm is not installed
(2/4): docker-ce-18.09.7-3.el7.x86_64.rpm                                                      |  19 MB  00:00:01  
(3/4): containerd.io-1.2.6-3.3.el7.x86_64.rpm                                                  |  26 MB  00:00:01  
(4/4): docker-ce-cli-18.09.7-3.el7.x86_64.rpm                                                  |  14 MB  00:00:00  
----------------------------------------------------------------------------------------------------------------------
Total                                                                                  29 MB/s |  59 MB  00:00:02  
Retrieving key from https://download.docker.com/linux/centos/gpg
Importing GPG key 0x621E9F35:
 Userid     : "Docker Release (CE rpm) "
 Fingerprint: 060a 61c5 1b55 8a7f 742b 77aa c52f eb6b 621e 9f35
 From       : https://download.docker.com/linux/centos/gpg
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : 2:container-selinux-2.99-1.el7_6.noarch                                                            1/4
setsebool:  SELinux is disabled.
  Installing : containerd.io-1.2.6-3.3.el7.x86_64                                                                 2/4
  Installing : 1:docker-ce-cli-18.09.7-3.el7.x86_64                                                               3/4
  Installing : 3:docker-ce-18.09.7-3.el7.x86_64                                                                   4/4
  Verifying  : 3:docker-ce-18.09.7-3.el7.x86_64                                                                   1/4
  Verifying  : 1:docker-ce-cli-18.09.7-3.el7.x86_64                                                               2/4
  Verifying  : containerd.io-1.2.6-3.3.el7.x86_64                                                                 3/4
  Verifying  : 2:container-selinux-2.99-1.el7_6.noarch                                                            4/4

Installed:
  docker-ce.x86_64 3:18.09.7-3.el7                                                                                  

Dependency Installed:
  container-selinux.noarch 2:2.99-1.el7_6  containerd.io.x86_64 0:1.2.6-3.3.el7  docker-ce-cli.x86_64 1:18.09.7-3.el7

Complete!

[root@mail ~]# systemctl start docker

[root@mail ~]# ps -ef | grep docker

root      82984      1  0 07:09 ?        00:00:00 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

root      83623  69874  0 07:09 pts/0    00:00:00 grep --color=auto docker

[root@mail ~]# docker info

Containers: 0

 Running: 0

 Paused: 0

 Stopped: 0

Images: 0

Server Version: 18.09.7

Storage Driver: overlay2

 Backing Filesystem: xfs

 Supports d_type: true

 Native Overlay Diff: true

Logging Driver: json-file

Cgroup Driver: cgroupfs

Plugins:

 Volume: local

 Network: bridge host macvlan null overlay

 Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog

Swarm: inactive

Runtimes: runc

Default Runtime: runc

Init Binary: docker-init

containerd version: 894b81a4b802e4eb2a91d1ce216b8817763c29fb

runc version: 425e105d5a03fabd737a126ad93d62a9eeede87f

init version: fec3683

Security Options:

 seccomp

  Profile: default

Kernel Version: 3.10.0-957.1.3.el7.x86_64

Operating System: CentOS Linux 7 (Core)

OSType: linux

Architecture: x86_64

CPUs: 1

Total Memory: 1.777GiB

Name: mail.naver.com

ID: 7XS6:53U6:SGZI:WRQU:QQJ4:T2W5:CRAW:JJL4:4CH4:NX3J:OF34:653B

Docker Root Dir: /var/lib/docker

Debug Mode (client): false

Debug Mode (server): false

Registry: https://index.docker.io/v1/

Labels:

Experimental: false

Insecure Registries:

 127.0.0.0/8

Live Restore Enabled: false

Product License: Community Engine

[root@mail ~]# docker -v
Docker version 18.09.7, build 2d0083d