docker的存储目录迁移

docker的默认存储目录是/var/lib/docker,目录结构如下:

[root@ztscshop docker]# cd /var/lib/docker [root@ztscshop docker]# ll total 64 drwx------ 2 root root 4096 Jan 24 2019 builder drwx------ 4 root root 4096 Jan 24 2019 buildkit drwx--x--x 3 root root 4096 Jan 24 2019 containerd drwx------ 4 root root 4096 Oct 24 15:05 containers drwx------ 3 root root 4096 Jan 24 2019 image drwxr-x--- 3 root root 4096 Jan 24 2019 network drwx------ 80 root root 16384 Oct 24 15:25 overlay2 drwx------ 4 root root 4096 Jan 24 2019 plugins drwx------ 2 root root 4096 Oct 22 11:57 runtimes drwx------ 2 root root 4096 Jan 24 2019 swarm drwx------ 2 root root 4096 Oct 24 15:13 tmp drwx------ 2 root root 4096 Jan 24 2019 trust drwx------ 15 root root 4096 Feb 7 2019 volumes [root@ztscshop docker]#  

docker所有自身的东西都会存在这些文件夹下面包括镜像文件和容器,所以会占用越来越多的磁盘空间。

如果docker所在的磁盘空间比较小,磁盘空间被占满没有空间的时候,显然会导致docker容器运行失败,此时必然要迁移docker的存储目录到一个更大的磁盘下面

1.查看磁盘占用情况:df -h

[root@ecs-8f49 ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 7.8G 0 7.8G 0% /dev tmpfs 7.8G 0 7.8G 0% /dev/shm tmpfs 7.8G 73M 7.7G 1% /run tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup /dev/vda1 40G 13G 25G 33% / tmpfs 1.6G 0 1.6G 0% /run/user/0 overlay 40G 13G 25G 33% /var/lib/docker/overlay2/53eb033fae8fadc98df74b118e743092fcd0ee68b579c2b771288c3c023b0b8b/merged shm 64M 0 64M 0% /var/lib/docker/containers/8ecb90f024c08468c5f32e7c8b8b0d1ff87616536e6c2155cfb58447bded3071/shm 

2.查看docker自身的内存占用:docker system df

[root@ecs-8f49 ~]# docker system df TYPE TOTAL ACTIVE SIZE RECLAIMABLE Images 16 12 2.893 GB 1.535 GB (53%) Containers 12 1 155.6 MB 155.6 MB (100%) Local Volumes 1 1 4.212 GB 0 B (0%) 

3.docker system prune命令可以用于清理磁盘,删除关闭的容器、无用的数据卷和网络,以及dangling镜像(即无tag的镜像)。

[root@ecs-8f49 ~]# docker system prune WARNING! This will remove:
        - all stopped containers
        - all volumes not used by at least one container
        - all networks not used by at least one container
        - all dangling images
    Are you sure you want to continue? [y/N] y
    Deleted Containers: 9bd48276fcd28b3882605fd67a156a7ea848f8fbfe16c3588b630955dfda253d 74af4504bdefbc58b83a476c12d6ce10260f91349eed0e5bfca5e51b86fb8474
    d405d43eeb7908472b4b8712f668ca3b97f3796f6afc1c1d19a15879140ddf64 9f645670de22840d04249351d07b2f68f77754e4dfebdb4b39c56d827d6b6805 79d32c6b3c34bb359cbbf8309d7be34074da391d3b48083f456a5911259a5213
    ad7137d7e018144e17790a3c86a8217a95faecd07a39003bc4df275c8c8d351d
    b02eb42677a52663e50fc4a2b1344d37a8d2a2cca445fe5eae49648a0ca54b13 0813454a5421cf380b72265c2e6832411a590479424dbc3470e47e1cc9cdd740
    a58b5f545ce1cd03a2899ba277641b5f52203802d9672c72f281f2d5a31fc219 936e65f72c60d754cb2a1441d0cdeb18f9a7ebde353f091fc44a034733fed52c
    ad86565bd85af04f5847703ba213d226c7d7b69e5210211e4170671d3ea4051c

    Deleted Volumes: 37620879ca58c052c47e7677a1851f45c25cbc0437c8883cc2fe8e70e1cb921a

    Total reclaimed space: 4.368 GB

4.docker system prune -a命令清理得更加彻底,可以将没有容器使用Docker镜像都删掉。注意,这两个命令会把你暂时关闭的容器,以及暂时没有用到的Docker镜像都删掉了…所以使用之前一定要想清楚.。我没用过,因为会清理 没有开启的 Docker 镜像。

5.迁移/var/lib/docker目录。

5.1 停止docker服务

systemctl stop docker

5.2 创建新的docker目录,执行命令df -h,找一个大的磁盘。 我在 /home目录下面建了 /home/docker/lib目录,执行的命令是:

mkdir -p /home/docker/lib

5.3 迁移/var/lib/docker目录下面的文件到 /home/docker/lib:

(rsync是linux文件夹同步的命令,参数要加一个-r,因为文件夹要递归copy,如果在同一台服务器上面,直接cp也是可以的)

 

rsync -r -avz /var/lib/docker /home/docker/lib/

5.4 配置 /etc/systemd/system/docker.service.d/devicemapper.conf。查看 devicemapper.conf 是否存在。如果不存在,就新建。

mkdir -p /etc/systemd/system/docker.service.d/
    vi /etc/systemd/system/docker.service.d/devicemapper.conf

5.5 然后在 devicemapper.conf 写入:(同步的时候把父文件夹一并同步过来,实际上的目录应在 /home/docker/lib/docker )

[Service] ExecStart= ExecStart=/usr/bin/dockerd --graph=/home/docker/lib/docker

5.6 重新加载 docker

 systemctl daemon-reload   systemctl restart docker   systemctl enable docker 

5.7 为了确认一切顺利,运行

docker info 

命令检查Docker 的根目录.它将被更改为 /home/docker/lib/docker

... Docker Root Dir: /home/docker/lib/docker Debug Mode (client): false Debug Mode (server): false Registry: https://index.docker.io/v1/ ... 

5.8 启动成功后,再确认之前的镜像还在:

root@nn0:~$ docker images REPOSITORY TAG IMAGE ID CREATED SIZE AAA/AAA v2 7331b8651bcc 27 hours ago 3.85GB BBB/BBB v1 da4a80dd8424 28 hours ago 3.47GB

5.9 确定容器没问题后删除/var/lib/docker/目录中的文件。

6.迁移/var/lib/docker目录后,Docker无法启动 (error initializing graphdriver: driver not supported)

启动信息

[root@nn0 ~]# systemctl start docker Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.

启动详情

8 31 01:47:25 localhost.localdomain systemd[1]: Starting Docker Application Container Engine... -- Subject: Unit docker.service has begun start-up -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit docker.service has begun starting up. 8 31 01:47:25 localhost.localdomain dockerd[2390]: time="2018-08-31T01:47:25.197015872+08:00" level=info msg="libcontainerd: new containerd process, pid: 2393"
    8月 31 01:47:26 localhost.localdomain dockerd[2390]: time="2018-08-31T01:47:26.204103195+08:00" level=error msg="[graphdriver] prior storage driver overlay2 failed: driver not supported" 8 31 01:47:26 localhost.localdomain dockerd[2390]: Error starting daemon: error initializing graphdriver: driver not supported 8 31 01:47:26 localhost.localdomain systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE 8 31 01:47:26 localhost.localdomain systemd[1]: Failed to start Docker Application Container Engine. 

错误原因:error initializing graphdriver: driver not supported

解决办法:在 /etc/docker 目录下创建daemon.json文件,并且加入以下配置

touch daemon.json  vi daemon.json  { "storage-driver": "overlay2", "storage-opts": [ "overlay2.override_kernel_check=true" ]
    }

再次启动:systemctl start docker

7. docker-runc not installed on system 问题

问题描述

docker运行镜像的时候,报错如下:
(如果报错端口映射的错误,那就先不映射端口直接启动镜像,试一下是不是这个错误,因为如果直接映射端口启动镜像的话,这个错误导致容器启动失败,但是报错是端口映射失败)

[root@nn0 k8s]# docker run -it registry.helloworld.com/test/atsd:latest bash WARNING: IPv4 forwarding is disabled. Networking will not work.
    /usr/bin/docker-current: Error response from daemon: shim error: docker-runc not installed on system.

问题解决:

[root@nn0 k8s]# cd /usr/libexec/docker/ [root@nn0 docker]# ln -s docker-runc-current docker-runc
较验修改是否生效
docker info|grep "Root Dir"