修改docker镜像的默认存储目录

1.首先停掉docker

# systemctl stop docker

2.修改系统服务的docker启动文件

[root@ecs docker]# vi /usr/lib/systemd/system/docker.service 

[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.com
After=network.target rhel-push-plugin.socket registries.service
Wants=docker-storage-setup.service
Requires=docker-cleanup.timer

[Service]
Type=notify
NotifyAccess=all
EnvironmentFile=-/run/containers/registries.conf
EnvironmentFile=-/etc/sysconfig/docker
EnvironmentFile=-/etc/sysconfig/docker-storage
EnvironmentFile=-/etc/sysconfig/docker-network
Environment=GOTRACEBACK=crash
Environment=DOCKER_HTTP_HOST_COMPAT=1
Environment=PATH=/usr/libexec/docker:/usr/bin:/usr/sbin
ExecStart=/usr/bin/dockerd-current 
          -g /datas/storage/docker   #添加你自己的新的存储镜像的目录
          --add-runtime docker-runc=/usr/libexec/docker/docker-runc-current 
          --default-runtime=docker-runc 
          --exec-opt native.cgroupdriver=systemd 
          --userland-proxy-path=/usr/libexec/docker/docker-proxy-current 
          --init-path=/usr/libexec/docker/docker-init-current 
          --seccomp-profile=/etc/docker/seccomp.json 
          $OPTIONS 
          $DOCKER_STORAGE_OPTIONS 
          $DOCKER_NETWORK_OPTIONS 
          $ADD_REGISTRY 
          $BLOCK_REGISTRY 
          $INSECURE_REGISTRY 
          $REGISTRIES
ExecReload=/bin/kill -s HUP $MAINPID
LimitNOFILE=1048576
LimitNPROC=1048576
LimitCORE=infinity
TimeoutStartSec=0
Restart=on-abnormal
KillMode=process

[Install]
WantedBy=multi-user.target

3.重新加载守护进程

# systemctl daemon-reload

4.重启docker服务

systemctl start docker

5.验证结果

（1）

[root@ecs]# docker info
Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 0
Server Version: 1.13.1
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: journald
Cgroup Driver: systemd
Plugins: 
 Volume: local
 Network: bridge host macvlan null overlay
Swarm: inactive
Runtimes: docker-runc runc
Default Runtime: docker-runc
Init Binary: /usr/libexec/docker/docker-init-current
containerd version:  (expected: aa8187dbd3b7ad67d8e5e3a15115d3eef43a7ed1)
runc version: e9c345b3f906d5dc5e8100b05ce37073a811c74a (expected: 9df8b306d01f59d3a8029be411de015b7304dd8f)
init version: 5b117de7f824f3d3825737cf09581645abbe35d4 (expected: 949e6facb77383876aeff8a6944dde66b3089574)
Security Options:
 seccomp
  WARNING: You're not using the default seccomp profile
  Profile: /etc/docker/seccomp.json
Kernel Version: 3.10.0-693.11.1.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
Number of Docker Hooks: 3
CPUs: 4
Total Memory: 7.639 GiB
Name: ecs-d68e-0003.novalocal
ID: 2UIG:WL75:4G6D:2VFS:YL7I:2OLN:O6IU:TTZQ:DBY2:F5VW:QOJQ:QJFS
Docker Root Dir: /datas/storage/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
WARNING: bridge-nf-call-iptables is disabled
WARNING: bridge-nf-call-ip6tables is disabled
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false
Registries: docker.io (secure)
 

（2）

[root@ecs docker]# cd /datas/storage/docker/
[root@ecs docker]# ls
containers  image  network  overlay2  plugins  swarm  tmp  trust  volumes

完成