docker 数据卷类型

[lvycoder]

前言

docker 的镜像是分层设计,镜像层是只读的,通过镜像启动的容器添加了一层可读写的文件系统,用户写入的数据都保存在这一层 如果要将写入到容器的数据永久保存,则需要将容器的数据保存在宿主机的指定目录.

• 1. 通过以下命令可以查看容器的数据目录信息

     [pre] root@m1:/home/lixie# docker inspect 99a1202bd98a | jq '.[].GraphDriver'
     {
     "Data": {
     "LowerDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20-init/diff:/var/lib/docker/overlay2/9a9dfb4184248a5a40fd1b6fa8aaf8e89dd44168c2e7222c2f152aec72a553bc/diff",
     "MergedDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20/merged",
     "UpperDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20/diff",
     "WorkDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20/work"
     },
     "Name": "overlay2"
     }

• 2. 此时我们停止 ubuntu 容器(GraphDriver依然存在)

     [pre] root@m1:/home/lixie# docker ps -a  |grep ubuntu
     99a1202bd98a   ubuntu:22.04                                                    "/bin/bash"               12 minutes ago   Exited (137) 5 seconds ago                                               ubuntu
     [pre] root@m1:/home/lixie#
     [pre] root@m1:/home/lixie# docker inspect 99a1202bd98a | jq '.[].GraphDriver'
     {
     "Data": {
     "LowerDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20-init/diff:/var/lib/docker/overlay2/9a9dfb4184248a5a40fd1b6fa8aaf8e89dd44168c2e7222c2f152aec72a553bc/diff",
     "MergedDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20/merged",
     "UpperDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20/diff",
     "WorkDir": "/var/lib/docker/overlay2/e6b65593cb86b4a72aa6e5ae540e6dbabcede9227d166f184d50bebcf7c2ff20/work"
     },
     "Name": "overlay2"
     }

• 如果删除 ubuntu 容器查看(发现容器信息全部被删除)

  [pre] root@m1:/home/lixie# docker rm 99a1202bd98a
  99a1202bd98a
  [pre] root@m1:/home/lixie# docker inspect 99a1202bd98a | jq '.[].GraphDriver'
  Error: No such object: 99a1202bd98a