docker深入1-docker的数据卷
参考： http://docs.docker.com/userguide/dockervolumes/ 针对数据的存储，有个data volume的概念。 使用参数： -v 在container中创建一个volume，或者类似目录映射的方式，挂载一个数据盘或者目录到docker的container中。 环境准备： [root@svr200-10 ~]# yum install docker-io -y [root@svr200-10 ~]# docker -v Docker version 1.5.0, build a8a31ef/1.5.0 [root@svr200-10 ~]# service docker start [root@svr200-10 ~]# useradd Jack && usermod -a -G docker Jack [root@svr200-10 ~]# su Jack [Jack@svr200-10 bin]$ docker pull centos [Jack@svr200-10 bin]$ docker p_w_picpaths REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE centos 7 fd44297e2ddb 11 days ago 215.7 MB centos centos7 fd44297e2ddb 11 days ago 215.7 MB centos latest fd44297e2ddb 11 days ago 215.7 MB 一、简单的方式是：挂载一个数据目录到container中 [Jack@svr200-10 bin]$ docker run -d -it -v /home/datacenter:/datacenter --name datacenter centos 66f5e0e0e7042e371c092ff24117598055b7f65d4224f9738efbf13ba6273127 [Jack@svr200-10 bin]$ docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 66f5e0e0e704 centos:7 "/bin/bash" 12 seconds ago Up 11 seconds datacenter [Jack@svr200-10 bin]$ docker attach test01 [root@66f5e0e0e704 /]# ll / total 60 lrwxrwxrwx. 1 root root 7 Apr 15 14:28 bin -> usr/bin drwxr-xr-x. 2 root root 4096 May 4 02:55 datacenter drwxr-xr-x. 5 root root 380 May 4 02:51 dev drwxr-xr-x. 47 root root 4096 May 4 02:51 etc drwxr-xr-x. 2 root root 4096 Jun 10 2014 home lrwxrwxrwx. 1 root root 7 Apr 15 14:28 lib -> usr/lib lrwxrwxrwx. 1 root root 9 Apr 15 14:28 lib64 -> usr/lib64 drwx------. 2 root root 4096 Apr 15 14:26 lost+found drwxr-xr-x. 2 root root 4096 Jun 10 2014 media drwxr-xr-x. 2 root root 4096 Jun 10 2014 mnt drwxr-xr-x. 2 root root 4096 Jun 10 2014 opt dr-xr-xr-x. 235 root root 0 May 4 02:51 proc dr-xr-x---. 2 root root 4096 Apr 15 14:29 root drwxr-xr-x. 10 root root 4096 Apr 15 14:29 run lrwxrwxrwx. 1 root root 8 Apr 15 14:28 sbin -> usr/sbin drwxr-xr-x. 2 root root 4096 Jun 10 2014 srv dr-xr-xr-x. 13 root root 0 May 4 02:51 sys -rw-r--r--. 1 root root 11 May 4 02:52 test01 -rw-r--r--. 1 root root 11 May 4 02:52 test04 drwxrwxrwt. 7 root root 4096 May 4 02:51 tmp drwxr-xr-x. 13 root root 4096 Apr 15 14:28 usr drwxr-xr-x. 19 root root 4096 Apr 15 14:29 var [root@66f5e0e0e704 /]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/docker-252:0-262241-66f5e0e0e7042e371c092ff24117598055b7f65d4224f9738efbf13ba6273127 9.8G 254M 9.0G 3% / tmpfs 1.9G 0 1.9G 0% /dev shm 64M 0 64M 0% /dev/shm /dev/mapper/vg_svr20010-lv_root 50G 9.3G 38G 20% /etc/hosts /dev/mapper/vg_svr20010-lv_home 405G 48G 338G 13% /datacenter tmpfs 1.9G 0 1.9G 0% /proc/kcore 写入数据： [root@66f5e0e0e704 /]# echo "`date` aaa" >/datacenter/test01 [root@66f5e0e0e704 /]# echo "`date` 123" >/datacenter/test02 [root@66f5e0e0e704 /]# ls /datacenter/ test01 test02 [root@66f5e0e0e704 /]# cat /datacenter/test0* Mon May 4 02:57:19 UTC 2015 aaa Mon May 4 02:57:27 UTC 2015 123 [root@66f5e0e0e704 /]# exit exit 查看宿主机挂载目录的文件和内容： [Jack@svr200-10 bin]$ ll /home/datacenter total 8 -rw-r--r--. 1 root root 33 May 4 10:57 test01 -rw-r--r--. 1 root root 33 May 4 10:57 test02 [Jack@svr200-10 bin]$ cat /home/datacenter/test0* Mon May 4 02:57:19 UTC 2015 aaa Mon May 4 02:57:27 UTC 2015 123 [Jack@svr200-10 bin]$ docker stop datacenter datacenter [Jack@svr200-10 bin]$ docker rm datacenter datacenter 二、复杂一点儿：创建一个data volume container，共享给其他container 如官网所示： If you have some persistent data that you want to share between containers, or want to use from non-persistent containers, it's best to create a named Data Volume Container, and then to mount the data from it. 1）创建一个container，提供一个数据卷供其他container使用： [Jack@svr200-10 bin]$ docker run -d -it -v /home/datacenter:/datacenter --name Data_Vol centos 7691eccc73f6e4e2e2c3d6816cf6ba6a80a5f98f5067d48db6e8bafb4e4db021 [Jack@svr200-10 bin]$ docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 7691eccc73f6 centos:7 "/bin/bash" 7 seconds ago Up 5 seconds Data_Vol 再创建2个container，使用刚才创建的数据卷Data_Vol来存储数据。 在启动container时，用这个参数：--volumes-from Data_Vol，而不是之前提到的-v参数，来挂载数据卷。 2）创建一个container：app1 ，写入一点儿数据 [Jack@svr200-10 bin]$ docker run -d -it --volumes-from Data_Vol --name app1 centos 1474f622b7f04c98da98e320d10864538b50b0b053677bbda039c8fb657062c1 [Jack@svr200-10 bin]$ docker attach app1 [root@1474f622b7f0 /]# ll / total 52 lrwxrwxrwx. 1 root root 7 Apr 15 14:28 bin -> usr/bin drwxr-xr-x. 2 root root 4096 May 4 02:56 datacenter drwxr-xr-x. 5 root root 380 May 4 03:40 dev drwxr-xr-x. 47 root root 4096 May 4 03:40 etc drwxr-xr-x. 2 root root 4096 Jun 10 2014 home lrwxrwxrwx. 1 root root 7 Apr 15 14:28 lib -> usr/lib lrwxrwxrwx. 1 root root 9 Apr 15 14:28 lib64 -> usr/lib64 drwx------. 2 root root 4096 Apr 15 14:26 lost+found drwxr-xr-x. 2 root root 4096 Jun 10 2014 media drwxr-xr-x. 2 root root 4096 Jun 10 2014 mnt drwxr-xr-x. 2 root root 4096 Jun 10 2014 opt dr-xr-xr-x. 244 root root 0 May 4 03:40 proc dr-xr-x---. 2 root root 4096 Apr 15 14:29 root drwxr-xr-x. 10 root root 4096 Apr 15 14:29 run lrwxrwxrwx. 1 root root 8 Apr 15 14:28 sbin -> usr/sbin drwxr-xr-x. 2 root root 4096 Jun 10 2014 srv dr-xr-xr-x. 13 root root 0 May 4 03:40 sys drwxrwxrwt. 7 root root 4096 May 4 03:40 tmp drwxr-xr-x. 13 root root 4096 Apr 15 14:28 usr drwxr-xr-x. 19 root root 4096 Apr 15 14:29 var [root@1474f622b7f0 /]# ls /datacenter/ test01 test02 [root@1474f622b7f0 /]# touch /datacenter/app1 [root@1474f622b7f0 /]# ls /datacenter/ app1 test01 test02 [root@1474f622b7f0 /]# echo "`date` hello app1" >/datacenter/app1 [root@1474f622b7f0 /]# cat /datacenter/app1 Mon May 4 03:43:11 UTC 2015 hello app1 [root@1474f622b7f0 /]# exit exit 2）再创建一个container：app2 ，写入一点儿数据 [Jack@svr200-10 bin]$ docker run -d -it --volumes-from Data_Vol --name app2 centos c4d743681ec95d78b21a52d3a558b4cab40a9f7ba43e884e4686c57c313b6923 [Jack@svr200-10 bin]$ docker attach app2 [root@c4d743681ec9 /]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/docker-252:0-262241-c4d743681ec95d78b21a52d3a558b4cab40a9f7ba43e884e4686c57c313b6923 9.8G 254M 9.0G 3% / tmpfs 1.9G 0 1.9G 0% /dev shm 64M 0 64M 0% /dev/shm /dev/mapper/vg_svr20010-lv_root 50G 9.3G 38G 20% /etc/hosts /dev/mapper/vg_svr20010-lv_home 405G 48G 338G 13% /datacenter tmpfs 1.9G 0 1.9G 0% /proc/kcore [root@c4d743681ec9 /]# ls /datacenter/ app1 test01 test02 [root@c4d743681ec9 /]# cat /datacenter/app1 Mon May 4 03:43:11 UTC 2015 hello app1 [root@c4d743681ec9 /]# echo "`date` this is app2" >/datacenter/app2 [root@c4d743681ec9 /]# exit exit [Jack@svr200-10 bin]$ docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c4d743681ec9 centos:7 "/bin/bash" 6 minutes ago Exited (0) 6 seconds ago app2 1474f622b7f0 centos:7 "/bin/bash" 6 minutes ago Exited (130) About a minute ago app1 7691eccc73f6 centos:7 "/bin/bash" 7 minutes ago Up 7 minutes Data_Vol [Jack@svr200-10 bin]$ 3）我们停止Data_Vol这个容器，再试试写入数据 [Jack@svr200-10 bin]$ docker stop Data_Vol Data_Vol [Jack@svr200-10 bin]$ [Jack@svr200-10 bin]$ docker start app1 app1 [Jack@svr200-10 bin]$ docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c4d743681ec9 centos:7 "/bin/bash" 7 minutes ago Exited (0) About a minute ago app2 1474f622b7f0 centos:7 "/bin/bash" 8 minutes ago Up 7 seconds app1 7691eccc73f6 centos:7 "/bin/bash" 8 minutes ago Exited (137) 16 seconds ago Data_Vol [Jack@svr200-10 bin]$ docker attach app1 [root@1474f622b7f0 /]# ls /datacenter/ app1 app2 test01 test02 [root@1474f622b7f0 /]# echo "`date` app1 is back here" >>/datacenter/app1 [root@1474f622b7f0 /]# cat /datacenter/app1 Mon May 4 03:43:11 UTC 2015 hello app1 Mon May 4 03:48:53 UTC 2015 app1 is back here [root@1474f622b7f0 /]# exit exit 看起来，，这个用来持久化的Data_Vol不用启动，，其他的container用--volumes-from Data_Vol来挂载数据卷，也是可以正常使用的。 4）回到宿主机了，我们看下数据 [Jack@svr200-10 bin]$ ls /home/datacenter/ app1 app2 test01 test02 看起来，文件都在这里呢，再看下数据： [Jack@svr200-10 bin]$ cat /home/datacenter/app1 Mon May 4 03:43:11 UTC 2015 hello app1 Mon May 4 03:48:53 UTC 2015 app1 is back here [Jack@svr200-10 bin]$ cat /home/datacenter/app2 Mon May 4 03:46:37 UTC 2015 this is app2 看，符合预期。
