Volume特点

1. 持久化存储文件
2. 容器间共享文件
3. 修改文件立即生效

docker提出的Vlolume概念，简单来说，就是目录
或者是文件，他可以绕过联合文件系统，而以
正常的文件或者目录的形式存于宿主机上

为容器添加卷

[root@bogon /]# docker run -dit --name test -v /test redis /bin/bash
root@9d7e5b04b3ac:/data# ls
root@9d7e5b04b3ac:/data# cd /
root@9d7e5b04b3ac:/# ls
bin  boot  data  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  test  tmp  usr  var
root@9d7e5b04b3ac:/# cd test
root@e96a304b9270:/test# echo "hello,docker">txt
[root@bogon /]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
e96a304b9270        redis               "docker-entrypoint..."   3 minutes ago       Up 3 minutes        6379/tcp            test
[root@bogon /]# docker inspect e96a304b9270
      "Mounts": [
            {
                "Type": "volume",
                "Name": "47e324fbd7beb5cc91e7b130108cab3e7c53cc86dcc1b6e3a020d18e878c8366",
                "Source": "/var/lib/docker/volumes/47e324fbd7beb5cc91e7b130108cab3e7c53cc86dcc1b6e3a020d18e878c8366/_data",
                "Destination": "/test",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            },
            {
                "Type": "volume",
                "Name": "cd005b9b9b79bfade620ea744741f51e4c05956ed890a0215e07ab6d26b0c94a",
                "Source": "/var/lib/docker/volumes/cd005b9b9b79bfade620ea744741f51e4c05956ed890a0215e07ab6d26b0c94a/_data",
                "Destination": "/data",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }
        ]

上面显示挂在了data和test到容器中

在宿主机中可以看到容器中的文件

[root@bogon /]# cat /var/lib/docker/volumes/47e324fbd7beb5cc91e7b130108cab3e7c53cc86dcc1b6e3a020d18e878c8366/_data/txt 
hello,docker

删除容器和相应的卷

docker rm -f -v test

运行一个容器，使用前面容器使用的卷,卷可以被多个容器共享

docker run -it --name test2 --volumes-from test nginx /bin/bash

注意：上面创建一个test2容器，使用到了test的卷，这样，即使删除了容器test，相应的卷也不会被删除;在test2中修改文件，可以同步到test

本地文件映射到容器

docker run -dit -v /test1/:/test1/ redis /bin/bash

用途：数据库文件放到本地硬盘

备份

[root@bogon ~]#docker run -dit --name test01 -v /test1 /bin/bash 
[root@bogon ~]#docker exec -it test01 /bin/bash
[root@f664684c31b1 /]# cat /test1/tt 
xxxxxxxxx
[root@f664684c31b1 /]# exit
[root@bogon ~]#docker run --volumes-from test01 -v $(pwd):/backup redis tar cvf /backup/backup.tar /test1
[root@bogon ~]# ls
backup.tar

#创建一个redis镜像的容器，共享test01容器的卷，打包test1目录，备份到本地磁盘

这个命令运行一个redis镜像的一个容器实例，共享test01容器的卷，把/test1打包成backup.tar,然后复制到本地

恢复到新容器中

[root@bogon ~]# docker run -v $(pwd):/backup redis tar xf /backup/backup.tar
[root@bogon ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                      PORTS               NAMES
ca884f53b748        redis               "docker-entrypoint..."   36 seconds ago      Exited (0) 35 seconds ago                       jovial_heisenberg
1c60f322e204        redis               "docker-entrypoint..."   25 minutes ago      Exited (0) 23 minutes ago                       naughty_lalande
86abe2926755        redis               "docker-entrypoint..."   25 minutes ago      Exited (2) 25 minutes ago                       priceless_heyrovsky
c23fea7f72ba        redis               "docker-entrypoint..."   26 minutes ago      Exited (2) 26 minutes ago                       thirsty_lovelace
f664684c31b1        b5e4ce650f0d        "/bin/bash"              About an hour ago   Up About an hour                                test01
[root@bogon ~]# docker run -dit --name recovery --volumes-from ca884f53b748 redis /bin/bash
7087d6e9db40f4870655b86ef767271cfb073f4b2c7ebe98633c5c053bd111a1
#ca884f53b748是前面解压的容器
[root@bogon ~]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
7087d6e9db40        redis               "docker-entrypoint..."   7 seconds ago       Up 6 seconds        6379/tcp            recovery
f664684c31b1        b5e4ce650f0d        "/bin/bash"              About an hour ago   Up About an hour                        test01
[root@bogon ~]# docker exec -it recovery /bin/bash
root@7087d6e9db40:/data# ls
test1
root@7087d6e9db40:/data# ls test1/
tt
root@7087d6e9db40:/data# cat test1/tt 
xxxxxxxxx
root@7087d6e9db40:/data# 
root@7087d6e9db40:/data# cd ..
root@7087d6e9db40:/# ls
backup    bin  boot  data  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
root@7087d6e9db40:/# ls backup/
anaconda-ks.cfg  backup.tar  centos_latest.tar
root@7087d6e9db40:/#