Docker容器数据卷的基本操作
一、概念
1.定义
卷就是目录或文件,存在于一个或多个容器中,由docker挂载到容器,但不属于联合文件系统,因此能够绕过Union File System提供一些用于持续存储或共享数据的特性。
卷的设计目的就是数据的持久化,完全独立于容器的生存周期,因此Docker不会在容器删除时删除其挂载的数据卷
2.作用:
- 将运用与运行的环境打包镜像,run后形成容器实例运行 ,但是我们对数据的要求希望是持久化的。
- Docker容器产生的数据,如果不备份,那么当容器实例删除后,容器内的数据自然也就没有了。
- 为了能保存数据在docker中则使用卷。
3.特点:
- 数据卷可在容器之间共享或重用数据
- 卷中的更改可以直接实时生效
- 数据卷中的更改不会包含在镜像的更新中
- 数据卷的生命周期一直持续到没有容器使用它为止
二、添加容器卷
运行一个带有容器卷存储功能的容器实例:docker run -it --privileged=true -v /宿主机绝对路径目录:/容器内目录 镜像名
Docker挂载主机目录访问如果出现cannot open directory .: Permission denied
解决办法:在挂载目录后多加一个--privileged=true参数
1.宿主vs容器之间映射添加容器卷
容器操作:
hongcaixia@hongcaixiadeMacBook-Pro ~ % docker run -it --privileged=true -v /Users/hongcaixia/Documents/host_data:/tmp/docker_data --name=my_centos centos [root@c61d4745b6e8 /]# cd /tmp/docker_data [root@c61d4745b6e8 docker_data]# ls [root@c61d4745b6e8 docker_data]# touch docker.txt [root@c61d4745b6e8 docker_data]# ls docker.txt [root@c61d4745b6e8 docker_data]# ls -- 宿主机在该目录建立了host.txt docker.txt host.txt [root@c61d4745b6e8 docker_data]# echo 'write in docker'>docker.txt [root@c61d4745b6e8 docker_data]# cat docker.txt write in docker [root@c61d4745b6e8 docker_data]# cat docker.txt -- 宿主机在该文件写入了write in host write in docker write in host [root@c61d4745b6e8 docker_data]#
主机操作:
hongcaixia@hongcaixiadeMacBook-Pro ~ % cd /Users/hongcaixia/Documents/host_data hongcaixia@hongcaixiadeMacBook-Pro host_data % ls docker.txt hongcaixia@hongcaixiadeMacBook-Pro host_data % touch host.txt hongcaixia@hongcaixiadeMacBook-Pro host_data % ls docker.txt host.txt hongcaixia@hongcaixiadeMacBook-Pro host_data % vi docker.txt hongcaixia@hongcaixiadeMacBook-Pro host_data % cat docker.txt write in docker write in host hongcaixia@hongcaixiadeMacBook-Pro host_data %
使用docker inspect 容器id 命令查看容器挂载信息:
hongcaixia@hongcaixiadeMacBook-Pro ~ % docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES dd1b08d9fd2a centos "/bin/bash" 14 minutes ago Up 14 minutes docker_centos hongcaixia@hongcaixiadeMacBook-Pro ~ % docker inspect dd1b08d9fd2a [ ... "Mounts": [ { "Type": "bind", "Source": "/Users/hongcaixia/Documents/host_data", "Destination": "/tmp/docker_data", "Mode": "", "RW": true, "Propagation": "rprivate" } ], ... ]
如果容器停止了,主机在挂载目录修改内容,当容器启动之后依旧可以同步到信息:
容器操作:
hongcaixia@hongcaixiadeMacBook-Pro ~ % docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES dd1b08d9fd2a centos "/bin/bash" 22 minutes ago Up 22 minutes docker_centos hongcaixia@hongcaixiadeMacBook-Pro ~ % docker stop dd1b08d9fd2a dd1b08d9fd2a hongcaixia@hongcaixiadeMacBook-Pro ~ % docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES hongcaixia@hongcaixiadeMacBook-Pro ~ % docker start dd1b08d9fd2a dd1b08d9fd2a hongcaixia@hongcaixiadeMacBook-Pro ~ % docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES dd1b08d9fd2a centos "/bin/bash" 24 minutes ago Up 2 seconds docker_centos hongcaixia@hongcaixiadeMacBook-Pro ~ % docker exec -it dd1b08d9fd2a bash [root@dd1b08d9fd2a /]# cd /tmp/docker_data/ [root@dd1b08d9fd2a docker_data]# ls docker.txt docker_in.txt docker_in.txt~ docker_in.txz~ host.txt host1.txt [root@dd1b08d9fd2a docker_data]#
主机操作:在容器停止之后创建host1.txt:
hongcaixia@hongcaixiadeMacBook-Pro host_data % touch host1.txt hongcaixia@hongcaixiadeMacBook-Pro host_data % ls docker.txt docker_in.txt docker_in.txt~ docker_in.txz~ host.txt host1.txt hongcaixia@hongcaixiadeMacBook-Pro host_data %
2.添加读写映射规则
默认是可读可写
设置只读限制:容器实例内部被限制,只能读取不能写 docker run -it --privileged=true -v /宿主机绝对路径目录:/容器内目录:ro 镜像名
容器操作:
hongcaixia@hongcaixiadeMacBook-Pro ~ % docker run -it --privileged=true -v /Users/hongcaixia/Documents/host_data2:/tmp/docker_data2:ro --name=hcx_centos2 centos [root@f12971f08fb1 /]# ls bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var [root@f12971f08fb1 /]# cd /tmp/docker_data2/ [root@f12971f08fb1 docker_data2]# ls -- 在主机中创建的文件 host.txt [root@f12971f08fb1 docker_data2]# touch docker.txt touch: cannot touch 'docker.txt': Read-only file system [root@f12971f08fb1 docker_data2]#
主机操作:
hongcaixia@hongcaixiadeMacBook-Pro Documents % cd host_data2 hongcaixia@hongcaixiadeMacBook-Pro host_data2 % ls hongcaixia@hongcaixiadeMacBook-Pro host_data2 % touch host.txt hongcaixia@hongcaixiadeMacBook-Pro host_data2 % ls host.txt hongcaixia@hongcaixiadeMacBook-Pro host_data2 %
三、卷的继承和共享
docker run -it --privileged=true --volumes-from 父类 --name 容器名 镜像名
第一个容器my_centos3:
hongcaixia@hongcaixiadeMacBook-Pro ~ % docker run -it --privileged=true -v /Users/hongcaixia/Documents/host_data3:/tmp/docker_data3 --name=my_centos3 centos [root@1e7c088b1b4d /]# cd /tmp/docker_data3 [root@1e7c088b1b4d docker_data3]# ls [root@1e7c088b1b4d docker_data3]# touch docker3.txt [root@1e7c088b1b4d docker_data3]# ls docker3.txt [root@1e7c088b1b4d docker_data3]# ls docker3.txt docker4.txt [root@1e7c088b1b4d docker_data3]# ls docker3.txt docker4.txt host.txt [root@1e7c088b1b4d docker_data3]# -- 停掉父容器,不影响子容器和主机的同步 hongcaixia@hongcaixiadeMacBook-Pro ~ % docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 671ef51c2961 centos "/bin/bash" 6 minutes ago Up 6 minutes my_centos4 hongcaixia@hongcaixiadeMacBook-Pro ~ % docker stop 671ef51c2961 671ef51c2961 hongcaixia@hongcaixiadeMacBook-Pro ~ % docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES hongcaixia@hongcaixiadeMacBook-Pro ~ % -- 父容器恢复,主机和子容器的操作可以同步过来 hongcaixia@hongcaixiadeMacBook-Pro ~ % docker start 671ef51c2961 671ef51c2961 hongcaixia@hongcaixiadeMacBook-Pro ~ % docker exec -it 671ef51c2961 /bin/bash [root@671ef51c2961 /]# cd /tmp/docker_data3/ [root@671ef51c2961 docker_data3]# ls docker3.txt docker4.txt host.txt host2.txt [root@671ef51c2961 docker_data3]#
第二个容器my_centos4: 继承3的容器卷
hongcaixia@hongcaixiadeMacBook-Pro ~ % docker run -it --privileged=true --volumes-from my_centos3 --name=my_centos4 centos [root@671ef51c2961 /]# cd /tmp/docker_data3 [root@671ef51c2961 docker_data3]# ls docker3.txt [root@671ef51c2961 docker_data3]# touch docker4.txt [root@671ef51c2961 docker_data3]# ls docker3.txt docker4.txt host.txt [root@671ef51c2961 docker_data3]# -- 停掉父容器,不影响子容器和主机的同步 [root@671ef51c2961 docker_data3]# ls docker3.txt docker4.txt host.txt host2.txt [root@671ef51c2961 docker_data3]#
主机:
hongcaixia@hongcaixiadeMacBook-Pro Documents % cd host_data3 hongcaixia@hongcaixiadeMacBook-Pro host_data3 % ls hongcaixia@hongcaixiadeMacBook-Pro host_data3 % ls docker3.txt hongcaixia@hongcaixiadeMacBook-Pro host_data3 % ls docker3.txt docker4.txt hongcaixia@hongcaixiadeMacBook-Pro host_data3 % touch host.txt hongcaixia@hongcaixiadeMacBook-Pro host_data3 % ls docker3.txt docker4.txt host.txt hongcaixia@hongcaixiadeMacBook-Pro host_data3 % hongcaixia@hongcaixiadeMacBook-Pro host_data3 % touch host2.txt hongcaixia@hongcaixiadeMacBook-Pro host_data3 % ls docker3.txt docker4.txt host.txt host2.txt hongcaixia@hongcaixiadeMacBook-Pro host_data3 %
父容器stop,不会影响子容器和主机之间的同步
到此这篇关于Docker容器数据卷的基本操作的文章就介绍到这了,更多相关Docker容器数据卷内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!
相关文章
使用Docker配置redis sentinel哨兵的方法步骤
本文主要介绍了Docker配置redis sentinel哨兵的方法步骤,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友们下面随着小编来一起学习学习吧2022-07-07
最新评论