更改Centos7 Docker 1.12文件系统为overlay

1. Centos 系统Docker默认文件存储使用devicemapper (loop), 官方建议生产环境下将默认的devicemapper (loop) 方式改为devicemapper (direct-lvm).
2. 本文直接将默认的devicemapper 改为 overlay
3. 需要删除Docker默认的/var/lib/docker 数据 (原有数据回丢失!)

查看Docker 信息

[[email protected]~]# docker info
Containers: 
 Running: 
 Paused: 
 Stopped: 
Images: 
Server Version: 
Storage Driver: devicemapper
...
           

停止Docker服务

删除Docker数据

增加overlay module

[[email protected]~]# echo "overlay" > /etc/modules-load.d/overlay.conf
           

重启主机

确认overlay生效

[[email protected]~]# lsmod |grep over
overlay         
           

修改Docker启动方式,指定storage-driver

[root@~]# mkdir -p /etc/systemd/system/docker.service.d
[root@~]# cat >/etc/systemd/system/docker.service.d/override.conf<<EOF
[Service] 
ExecStart= 
ExecStart=/usr/bin/docker daemon --storage-driver=overlay
EOF
           

启动Docker daemon

[[email protected]~]# service docker start
Redirecting to /bin/systemctl start  docker.service
           

[[email protected]~]# docker info |grep overlay
Storage Driver: overlay
...
           

修改后Docker启动失败, 重装Docker

[[email protected]~]#rpm -qa |grep docker
docker-engine-selinux--el7.centos.noarch
docker-engine--el7.centos.x86_64
           

下面使用的是1.12 实验版本

[root@~]# cat > /etc/yum.repos.d/docker.repo <<-EOF
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/experimental/centos/7/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF