Docker各种目录的作用

来源：互联网发布：食物热量软件编辑：程序博客网时间：2024/04/30 22:16

查看一下宿主机的分区挂载情况

[root@localhost ~]# dfFilesystem              1K-blocks     Used Available Use% Mounted on/dev/mapper/centos-root  52403200 26388668  26014532  51% /devtmpfs                  1923288        0   1923288   0% /devtmpfs                     1933472        0   1933472   0% /dev/shmtmpfs                     1933472    17200   1916272   1% /runtmpfs                     1933472        0   1933472   0% /sys/fs/cgroup/dev/mapper/centos-home  47760604    32928  47727676   1% /home/dev/sda1                  508588   155828    352760  31% /boottmpfs                      386696        0    386696   0% /run/user/0

同时运行两个个容器，一个基于busybox镜像，一个基于ubuntu镜像

[root@localhost /]# docker run -it busybox /bin/sh[root@localhost ~]# docker run -it ubuntu /bin/bash

可以看到两个个运行的容器：

[root@localhost ~]# docker ps -aCONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES29f3173876a6        busybox             "/bin/sh"           20 seconds ago      Up 18 seconds                           agitated_jones720a3161bf18        ubuntu              "/bin/bash"         3 minutes ago       Up 3 minutes                            wizardly_khorana

再次查看分区挂载情况：

[root@localhost ~]# dfFilesystem              1K-blocks     Used Available Use% Mounted on/dev/mapper/centos-root  52403200 26388668  26014532  51% /devtmpfs                  1923288        0   1923288   0% /devtmpfs                     1933472        0   1933472   0% /dev/shmtmpfs                     1933472    17200   1916272   1% /runtmpfs                     1933472        0   1933472   0% /sys/fs/cgroup/dev/mapper/centos-home  47760604    32928  47727676   1% /home/dev/sda1                  508588   155828    352760  31% /boottmpfs                      386696        0    386696   0% /run/user/0/dev/dm-4                10474496    34660  10439836   1% /var/lib/docker/devicemapper/mnt/2b35dda0f86ac7d4700621892343a498ea9ff8eb2ca9bcc2599456de997258a3shm                         65536        0     65536   0% /var/lib/docker/containers/a18d392e6d01cb7ab9dfcf728a1cd50fd1b4db087a9c3b3373db7f37d594f35a/shm/dev/dm-5                10474496   141224  10333272   2% /var/lib/docker/devicemapper/mnt/5ea73d5812e830cf15918fecec87e4119ade209c7af9342dca60f86d67d3ab4fshm                         65536        0     65536   0% /var/lib/docker/containers/720a3161bf18a175136a25c065b97f045e481dd5ee46d4288ea08a58e4205f3d/shm

可以看到后面多出了四个分区，/dev/dm-4和/dev/dm-5分别对应两个容器的文件系统，使用tree命令查看两个挂载点的目录结构：

[root@localhost ~]# tree -L 2 /var/lib/docker/devicemapper/mnt/5ea73d5812e830cf15918fecec87e4119ade209c7af9342dca60f86d67d3ab4f/var/lib/docker/devicemapper/mnt/5ea73d5812e830cf15918fecec87e4119ade209c7af9342dca60f86d67d3ab4f├── id└── rootfs    ├── bin    ├── boot    ├── dev    ├── etc    ├── home    ├── lib    ├── lib64    ├── media    ├── mnt    ├── opt    ├── proc    ├── root    ├── run    ├── sbin    ├── srv    ├── sys    ├── tmp    ├── usr    └── var20 directories, 1 file[root@localhost ~]# tree -L 2 /var/lib/docker/devicemapper/mnt/2b35dda0f86ac7d4700621892343a498ea9ff8eb2ca9bcc2599456de997258a3/var/lib/docker/devicemapper/mnt/2b35dda0f86ac7d4700621892343a498ea9ff8eb2ca9bcc2599456de997258a3    ├── id    └── rootfs        ├── bin        ├── dev        ├── etc        ├── home        ├── proc        ├── root        ├── sys        ├── tmp        ├── usr        └── var    11 directories, 1 file

可以看出，两个目录中存放的是两个容器对应的文件系统根节点。

这时候，再运行一个容器基于镜像busybox，再次查看分区：

[root@localhost ~]# dfFilesystem              1K-blocks     Used Available Use% Mounted on/dev/mapper/centos-root  52403200 26388668  26014532  51% /devtmpfs                  1923288        0   1923288   0% /devtmpfs                     1933472        0   1933472   0% /dev/shmtmpfs                     1933472    17200   1916272   1% /runtmpfs                     1933472        0   1933472   0% /sys/fs/cgroup/dev/mapper/centos-home  47760604    32928  47727676   1% /home/dev/sda1                  508588   155828    352760  31% /boottmpfs                      386696        0    386696   0% /run/user/0/dev/dm-4                10474496    34660  10439836   1% /var/lib/docker/devicemapper/mnt/2b35dda0f86ac7d4700621892343a498ea9ff8eb2ca9bcc2599456de997258a3shm                         65536        0     65536   0% /var/lib/docker/containers/a18d392e6d01cb7ab9dfcf728a1cd50fd1b4db087a9c3b3373db7f37d594f35a/shm/dev/dm-5                10474496   141224  10333272   2% /var/lib/docker/devicemapper/mnt/5ea73d5812e830cf15918fecec87e4119ade209c7af9342dca60f86d67d3ab4fshm                         65536        0     65536   0% /var/lib/docker/containers/720a3161bf18a175136a25c065b97f045e481dd5ee46d4288ea08a58e4205f3d/shm/dev/dm-6                10474496    34660  10439836   1% /var/lib/docker/devicemapper/mnt/e5cb5359515b967a6af0a8e115ed343b8bc8c3df3f22645e0d3c8bd9de81851cshm                         65536        0     65536   0% /var/lib/docker/containers/29f3173876a6660ae495d15a28094e60f6a96106be483a4ad4ed39c4af29044b/shm

可以看到，又生成了两个分区，可见，每次启动一个容器，都会对应生成一个分区，并挂载到对应的容器id命名的目录中去，这个目录里面rootfs就是容器中对应的系统的根挂载点。

[root@localhost ~]# tree -L 2 /var/lib/docker/devicemapper/mnt/e5cb5359515b967a6af0a8e115ed343b8bc8c3df3f22645e0d3c8bd9de81851c/var/lib/docker/devicemapper/mnt/e5cb5359515b967a6af0a8e115ed343b8bc8c3df3f22645e0d3c8bd9de81851c├── id└── rootfs    ├── bin    ├── dev    ├── etc    ├── home    ├── mnt    ├── proc    ├── root    ├── sys    ├── tmp    ├── usr    └── var12 directories, 1 file

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