本篇内容介绍了“docker怎么管理容器的数据”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
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管理容器的数据
可以通过两种方式管理容器中的数据,数据卷(Data Volumns),数据卷容器(Data Volumns containers)
数据卷(Data Volumns)
概念:
data volume存在一个或多个容器中的特殊的目录,它绕过容器的Union File System.用来持久或共享数据.它是独立于容器的生命周期的. 它有几个特点:
容器创建好后会初始化数据卷.如果基础镜像在此挂载点上有数据,它会将数据复制到数据卷里.(挂在主机的目录则不会复制)
数据卷可以被多个容器共享使用
对数据卷的修改是直接的.
对数据卷的更改,不会因为你更新镜像而被包括进去.
就算容器被删除,数据卷还继续存在.
添加数据卷
[root@srv00 ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hippo/nginx v1 2e1513eeaa0a 2 days ago 281.1 MB
hippo/nginx v1.10 1e20546f8434 2 days ago 281.1 MB
[root@srv00 ~]# docker run -it -v /etc/nginx hippo/nginx:v1.10
[root@bab2e5725220 /]# ll /etc/nginx/
total 32
drwxr-xr-x 2 root root 25 May 20 07:40 conf.d
...
可以看到容器内的数据卷目录中,是原有的/etc/nginx目录的内容.
可以修改一个文件配置看看.并检查主机上对应的数据卷内容.
[root@srv00 ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
bab2e5725220 hippo/nginx:v1.10 "/bin/bash" About a minute ago Exited (0) 15 seconds ago hungry_jennings
[root@srv00 ~]# docker inspect bab2e5725220
...
"Mounts": [
{
"Name": "b6c506a65d5f495ca6ce06aeb30bb6472295d459bfbeb464e89681e17ffe3541",
"Source": "/var/lib/docker/volumes/b6c506a65d5f495ca6ce06aeb30bb6472295d459bfbeb464e89681e17ffe3541/_data",
"Destination": "/etc/nginx",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": ""
}
...
[root@srv00 _data]# docker rm bab2e5725220
bab2e5725220
[root@srv00 ~]# cat /var/lib/docker/volumes/b6c506a65d5f495ca6ce06aeb30bb6472295d459bfbeb464e89681e17ffe3541/_data/nginx.conf
...对数据卷的修改直接持久在主机对应的地方..就算容器已经关闭或删除.
挂载主机目录
[root@srv00 ~]# mkdir nginx
[root@srv00 ~]# docker run -it -v /root/nginx:/etc/nginx hippo/nginx:v1.10
[root@c0750f9779b3 /]# ll /etc/nginx/ <===无内容
[root@srv00 ~]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c0750f9779b3 hippo/nginx:v1.10 "/bin/bash" 23 seconds ago Exited (0) 11 seconds ago agitated_mclean
[root@srv00 ~]# docker inspect c0750f9779b3
...
"Mounts": [
{
"Source": "/root/nginx",
"Destination": "/etc/nginx",
"Mode": "",
"RW": true,
"Propagation": "rprivate"
}
...可以看到是主机的对应目录挂载到容器内.RW是可读写标志,效果和mount命令一致.
如果是相对目录:
[root@srv00 ~]# mkdir -p a/b
[root@srv00 ~]# touch a/b/c
[root@srv00 ~]# docker run -it -v a/b:/etc/nginx hippo/nginx:v1.10
docker: Error response from daemon: create a/b: "a/b" includes invalid characters for a local volume name, only "[a-zA-Z0-9][a-zA-Z0-9_.-]" are allowed.
See 'docker run --help'.
[root@srv00 ~]# docker run -it -v nginx:/etc/nginx hippo/nginx:v1.10
e4e2f137a7412f6474018e88985e2f605b5f77f2cd1ce27280142994e5feb030
[root@srv00 ~]# docker inspect e4e2f137a7412f6474018e88985e2f605b5f77f2cd1ce27280142994e5feb030
...
"Mounts": [
{
"Name": "nginx",
"Source": "/var/lib/docker/volumes/nginx/_data",
"Destination": "/etc/nginx",
"Driver": "local",
"Mode": "z",
"RW": true,
"Propagation": "rprivate"
}
...主机不可以指定相对目录,只可以对数据卷命名.
当然你可以以只读方式挂载.
[root@srv00 ~]# docker run -itd -v nginx:/etc/nginx:ro hippo/nginx:v1.10
b0a67f835eaac812ab37086bef05be6b0726ba080d73113221a5cf8a25bfb513
[root@srv00 ~]# docker inspect b0a67f835eaac812ab37086bef05be6b0726ba080d73113221a5cf8a25bfb513
...
"Mounts": [
{
"Name": "nginx",
"Source": "/var/lib/docker/volumes/nginx/_data",
"Destination": "/etc/nginx",
"Driver": "local",
"Mode": "ro",
"RW": false,
"Propagation": "rprivate"
}
...单独创建数据卷
之前都是通过运行容器的同时创建数据卷.当然也可以先创建好数据卷.然后挂载到容器中使用. 数据卷管理使用docker volume命令.我们看一下刚才创建了哪些数据卷.
[root@srv00 ~]# docker volume ls
DRIVER VOLUME NAME
local 0159a70ae1a86b5c2947d323b5e6d539101770b66af5cb0ba6d87c12a1c2c742
local b6c506a65d5f495ca6ce06aeb30bb6472295d459bfbeb464e89681e17ffe3541
local nginx
[root@srv00 ~]# docker volume inspect 0159a70ae1a86b5c2947d323b5e6d539101770b66af5cb0ba6d87c12a1c2c742
[
{
"Name": "0159a70ae1a86b5c2947d323b5e6d539101770b66af5cb0ba6d87c12a1c2c742",
"Driver": "local",
"Mountpoint": "/var/lib/docker/volumes/0159a70ae1a86b5c2947d323b5e6d539101770b66af5cb0ba6d87c12a1c2c742/_data",
"Labels": null
}
]
[root@srv00 ~]# docker volume inspect nginx
[
{
"Name": "nginx",
"Driver": "local",
"Mountpoint": "/var/lib/docker/volumes/nginx/_data",
"Labels": null
}
]Driver是local,就是映射到本地主机.也可以使用其他驱动.映射到比如iscsi,NFS,FC 等共享磁盘上.
我们来单独创建一个数据卷并使用
[root@srv00 ~]# docker volume create --name dbdata
dbdata
[root@srv00 ~]# docker volume ls
DRIVER VOLUME NAME
local 0159a70ae1a86b5c2947d323b5e6d539101770b66af5cb0ba6d87c12a1c2c742
local b6c506a65d5f495ca6ce06aeb30bb6472295d459bfbeb464e89681e17ffe3541
local dbdata
local nginx
[root@srv00 ~]# docker volume inspect dbdata
[
{
"Name": "dbdata",
"Driver": "local",
"Mountpoint": "/var/lib/docker/volumes/dbdata/_data",
"Labels": {}
}
]
[root@srv00 ~]# docker run -itd -v dbdata:/etc/nginx hippo/nginx:v1.10数据卷容器(Data Volumns containers)
我们先创建个数据卷容器.然后运行两个单独的容器,挂载数据卷容器.
[root@srv00 ~]# docker create -v /opt --name datastore centos
e5c37981c4f9e16f92b0d5215f5dfa5f79c86282e3018435a5e380350a5cce2c
[root@srv00 ~]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e5c37981c4f9 centos "/bin/bash" 11 seconds ago Created datastore
[root@srv00 ~]# docker run -itd --volumes-from datastore --name db1 centos
[root@srv00 ~]# docker run -itd --volumes-from datastore --name db2 centos
看看数据是否互相可访问.
[root@srv00 ~]# docker exec -it db1 /bin/bash
[root@cd8fa62d3b29 ~]# echo "db111111" > /opt/txt
[root@cd8fa62d3b29 ~]# exit
exit
[root@srv00 ~]# docker exec -it db2 /bin/bash
[root@72c21395c72b /]# cat /opt/txt
db111111
[root@72c21395c72b /]# exit
exit
[root@srv00 ~]# docker inspect datastore
[root@srv00 ~]# docker inspect db1
[root@srv00 ~]# docker inspect db2
...
"Mounts": [
{
"Name": "6b650687d6d2a448006dcb2b966b5f69bb31d34cf3e93f5e3c3460b6fd6eea4a",
"Source": "/var/lib/docker/volumes/6b650687d6d2a448006dcb2b966b5f69bb31d34cf3e93f5e3c3460b6fd6eea4a/_data",
"Destination": "/opt",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": ""
}
...
[root@srv00 ~]# docker volume inspect 6b650687d6d2a448006dcb2b966b5f69bb31d34cf3e93f5e3c3460b6fd6eea4a
[
{
"Name": "6b650687d6d2a448006dcb2b966b5f69bb31d34cf3e93f5e3c3460b6fd6eea4a",
"Driver": "local",
"Mountpoint": "/var/lib/docker/volumes/6b650687d6d2a448006dcb2b966b5f69bb31d34cf3e93f5e3c3460b6fd6eea4a/_data",
"Labels": null
}
]几个容器挂在的数据卷都是相同的.内部其实是创建了一个数据卷. 就算删除所有相关的运行的容器..数据卷不会删除.
“docker怎么管理容器的数据”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注创新互联网站，小编将为大家输出更多高质量的实用文章！
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