docker容器数据卷
Posted SmallForest
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背景
将应用和运行环境打包成一个镜像
为了数据安全，数据不能放在容器中
数据需要持久化存储
卷技术说白了，将容器内目录挂载到Linux中的目录，文件同步的机制
卷的目的：为了做持久化和同步，容器间也可以实现数据共享
使用数据卷 方式一
docker run -it -v 宿主机目录:容器内目录 centos /bin/bash
启动之后可以使用
docker inspect 容器id
查看Mounts
- 请手敲代码！
- code
#执行挂载命令-v
➜ ~ docker run -it -d --name centos01 -v /Users/dada/Downloads/docker-centos/etc:/etc centos
6080c9748915bd8c64d2cc218ff3f3431a155fd360be60620184eb80ba6a6add
#查看运行中的容器列表
➜ ~ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6080c9748915 centos "/bin/bash" 3 seconds ago Up 2 seconds centos01
#进入容器
➜ ~ docker exec -it 6080c9748915 /bin/bash
#进入etc 创建文件并写入数据
bash-4.4# cd /etc/
bash-4.4# touch index.html & echo \'hi! smallForest\'>index.html
# ls一下
bash-4.4# ls
hostname hosts index.html resolv.conf
# 退出容器
bash-4.4# exit
# 查看容器信息 inspect
➜ ~ docker inspect 6080c9748915
返回结果巨长，只写Mounts部分
"Mounts": [
{
"Type": "bind",
"Source": "/Users/dada/Downloads/docker-centos/etc",
"Destination": "/etc",
"Mode": "",
"RW": true,
"Propagation": "rprivate"
}
],
# 回到宿主机目录/Users/dada/Downloads/docker-centos/etc。校验index.html是否存在，内容是否是\'hi! smallForest\'容器停止宿主机修改文件重启后会同步吗？
- 请手敲命令
code
# 查看运行中的容器 ➜ ~ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 6080c9748915 centos "/bin/bash" 12 minutes ago Up 12 minutes centos01 # 停止容器 ➜ ~ docker stop 6080c9748915 6080c9748915 ➜ ~ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES #在宿主机中修改index.html追加一句话 ➜ ~ vim /Users/dada/Downloads/docker-centos/etc/index.html ➜ ~ cat /Users/dada/Downloads/docker-centos/etc/index.html hi! smallForest update on MacOS #启动容器 ➜ ~ docker start 6080c9748915 6080c9748915 #进入容器 ➜ ~ docker exec -it 6080c9748915 /bin/bash #进入配置目录 bash-4.4# cd /etc/ #查看index.html已经同步更新 bash-4.4# cat index.html hi! smallForest update on MacOS结论：容器停止宿主机修改文件重启后会同步
挂载到宿主机目录之后删除容器，数据会删除吗？
mysql数据同步 持久化问题。需要配置pwd
- code
docker run -d -p 3306:3306 -v /Users/dada/Downloads/docker-centos/mysql/conf:/etc/mysql/conf.d -v /Users/dada/Downloads/docker-centos/mysql/data:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 --name mysql01 mysql:5.7
Unable to find image \'mysql:5.7\' locally
5.7: Pulling from library/mysql
69692152171a: Already exists
1651b0be3df3: Pull complete
951da7386bc8: Pull complete
0f86c95aa242: Pull complete
37ba2d8bd4fe: Pull complete
6d278bb05e94: Pull complete
497efbd93a3e: Pull complete
a023ae82eef5: Pull complete
e76c35f20ee7: Pull complete
e887524d2ef9: Pull complete
ccb65627e1c3: Pull complete
Digest: sha256:a682e3c78fc5bd941e9db080b4796c75f69a28a8cad65677c23f7a9f18ba21fa
Status: Downloaded newer image for mysql:5.7
bcc85b93643d2c1cb84f786eed080f55d346a8df15260327a673b8cd98224d14
# 使用密码123456连接Navicat 并创建一个数据库
# 删除容器
➜ ~ docker stop bcc85b93643d & docker rm bcc85b93643d
➜ ~ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
#回到宿主机目录/Users/dada/Downloads/docker-centos/mysql/data 查看数据库文件是否存在结论：挂载到宿主机目录之后删除容器，数据不会删除
匿名挂载
-v 容器内目录！不指定宿主机路径
code
# 启动nginx容器，匿名挂载，-P表示自动指定端口 ➜ ~ docker run -d -P --name nginx01 -v /etc/nginx nginx:latest 8f2ea2ad93a0e3d98560c9f59e7d7f05a90375b909d7b265f14151e845256694 # 查看容器详情 ➜ ~ docker inspect 8f2ea2ad93a0 #简略展示 "Mounts": [ { "Type": "volume", "Name": "f50a729cba7814d70f11dbb0862c5aefc1b076b142c84bc5133986cdc2a869ce", "Source": "/var/lib/docker/volumes/f50a729cba7814d70f11dbb0862c5aefc1b076b142c84bc5133986cdc2a869ce/_data", "Destination": "/etc/nginx", "Driver": "local", "Mode": "", "RW": true, "Propagation": "" } ], # 查看本地所有卷的列表 ➜ ~ docker volume ls具名挂载
给卷设置名字
-v 卷名:容器内目录- code
# 创建nginx容器 具名挂载
➜ ~ docker run -d -P --name nginx03 -v juming-nginx:/etc/nginx nginx:latest
cae84c37d3f4278815fd7793b59b54250dfc65355d9748d30dcebe6bf0e1de2e
# 查看本地所有的卷
➜ ~ docker volume ls
DRIVER VOLUME NAME
local juming-nginx
local portainer_data
local user_cert
# 查看卷名“juming-nginx”的信息，Mountpoint就是宿主机存储文件位置
➜ ~ docker volume inspect juming-nginx
[
{
"CreatedAt": "2021-05-26T09:10:55Z",
"Driver": "local",
"Labels": null,
"Mountpoint": "/var/lib/docker/volumes/juming-nginx/_data",
"Name": "juming-nginx",
"Options": null,
"Scope": "local"
}
]
具名挂载方式方便找卷
区分匿名挂载，具名挂载，指定宿主路径挂载
- -v 容器内路径
- -v 卷名:容器内路径
- -v /宿主机路径:容器内路径
扩展知识：
-v juming-nginx:/etc/nginx:ro
ro rw 分别表示只读 读写
ro表示挂载的路径只能在宿主机内修改，不能在容器内修改
code ==失败中==
➜ ~ docker run -d -P --name nginx05 -v /Users/dada/Downloads/docker-centos/nginx/conf:/etc/nginx:ro nginx:latest ➜ ~ docker inspect 容器id使用数据卷 方式二
初识Dockerfile
Dockerfile就是用来构建docker镜像的构建文件，命令脚本，通过脚本可以生成镜像。- 可以完成数据卷挂载，
- 镜像生成 docker build -f Dockerfile -t 镜像名称:TAG . #末尾必须有个点
- 在Dockerfile文件的名字是Dockerfile的时候,docker build 可以不用指定-f
- code
# 打印当前路径
➜ file pwd
/Users/dada/Downloads/docker-centos/file
# file路径下执行创建文件命令
➜ file touch Dockerfile1
# 编辑文件写入内容
➜ file vim Dockerfile1
# 查看是否写入成功
➜ file cat Dockerfile1
FROM centos
VOLUME ["volume01","volume02"]
CMD echo "----end----"
CMD /bin/bash
# 命令行末尾缺少点 报错
➜ file docker build -f Dockerfile1 -t mycentos:02
"docker build" requires exactly 1 argument.
See \'docker build --help\'.
Usage: docker build [OPTIONS] PATH | URL | -
Build an image from a Dockerfile
# 命令增加点 生成成功
➜ file docker build -f Dockerfile1 -t mycentos:02 .
[+] Building 0.1s (5/5) FINISHED
=> [internal] load build definition from Dockerfile1 0.0s
=> => transferring dockerfile: 123B 0.0s
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/library/centos:latest 0.0s
=> CACHED [1/1] FROM docker.io/library/centos 0.0s
=> exporting to image 0.0s
=> => exporting layers 0.0s
=> => writing image sha256:231feafd3348cc7cb6a2eeed8b19effe7b15fd2a723a287669e6d06 0.0s
=> => naming to docker.io/library/mycentos:02 0.0s
Use \'docker scan\' to run Snyk tests against images to find vulnerabilities and learn how to fix them
# 查看新创建镜像
➜ file docker images|grep mycentos
mycentos 02 231feafd3348 5 months ago 209MB
➜ file
# 启动容器
➜ file docker run -d -it --name mycentos02 mycentos:02
0ff56e3d5516174f39c9eb63bbced886d8470d963ef6dcf77ce67082226860b9
#查看容器列表
➜ file docker ps|grep mycentos
0ff56e3d5516 mycentos:02 "/bin/sh -c /bin/bash" 37 seconds ago Up 36 seconds mycentos02
# inspect 查看容器数据卷挂载情况
➜ file docker inspect 0ff56e3d5516
"Mounts": [
{
"Type": "volume",
"Name": "15a00b422c3ad4f7eac181566b51fc10d40e546b06a8d57100375aa58a0cc2b1",
"Source": "/var/lib/docker/volumes/15a00b422c3ad4f7eac181566b51fc10d40e546b06a8d57100375aa58a0cc2b1/_data",
"Destination": "volume02",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": ""
},
{
"Type": "volume",
"Name": "9e520b5a5872379b57c8ade61125cedfd6f0e180712ade07d25d2d8808ce5a0a",
"Source": "/var/lib/docker/volumes/9e520b5a5872379b57c8ade61125cedfd6f0e180712ade07d25d2d8808ce5a0a/_data",
"Destination": "volume01",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": ""
}
],
......
# 可以查看到volume01 volume02挂载成功测试不加 -f 生成镜像
结论：在项目中Dockerfile文件的名字请使用“Dockerfile”，这是行业规范eg:composer.json go.mod等➜ file ls Dockerfile1 ➜ file mv Dockerfile1 Dockerfile ➜ file docker build -t mycentos1:03 . [+] Building 0.1s (5/5) FINISHED => [internal] load build definition from Dockerfile 0.0s => => transferring dockerfile: 122B 0.0s => [internal] load .dockerignore 0.0s => => transferring context: 2B 0.0s => [internal] load metadata for docker.io/library/centos:latest 0.0s => CACHED [1/1] FROM docker.io/library/centos 0.0s => exporting to image 0.0s => => exporting layers 0.0s => => writing image sha256:231feafd3348cc7cb6a2eeed8b19effe7b15fd2a723a287669e6d06e35aa6261 0.0s => => naming to docker.io/library/mycentos1:03 0.0s Use \'docker scan\' to run Snyk tests against images to find vulnerabilities and learn how to fix them ➜ file docker images|grep mycentos1 mycentos1 03 231feafd3348 5 months ago 209MB ➜ file容器数据卷可以实现的功能1
两个容器间数据同步，备份
举例：两个MySQL同步数据库数据- --volumes-from 两个容器数据同步命令
- code
# 启动3个容器
# docker01
➜ ~ docker run -d -it --name docker01 centos:latest
1a3e373b0d690d7f2c41577384e3a929d8c2067401d26eda2646e1547927952e
➜ ~ docker ps|grep docker0
1a3e373b0d69 centos:latest "/bin/bash" 55 seconds ago Up 54 seconds docker01
# docker02 docker01的数据会同步到docker02
➜ ~ docker run -d -it --name docker02 --volumes-from docker01 centos:latest
297b7cbf22910888056b991abbb8e7ef141ed92b58ff60171025f7cb39cc27f1
#docker03 docker01的数据会同步到docker03
➜ ~ docker run -d -it --name docker03 --volumes-from docker01 centos:latest
9c5366c63559aac7a78aa9eec0bd7933de4de475652780d9e6e1cd94a113838c
#docker01 02 03会使用共同的数据卷
➜ ~ docker ps|grep docker0
9c5366c63559 centos:latest "/bin/bash" 57 seconds ago Up 56 seconds docker03
297b7cbf2291 centos:latest "/bin/bash" About a minute ago Up About a minute docker02
1a3e373b0d69 centos:latest "/bin/bash" 5 minutes ago Up 5 minutes docker01
# 删除docker01对数据有什么影响吗？
# 删除docker01对02 03没有影响，数据依旧在，备份机制- MySQL数据同步例子
code
# mysql01 ➜ ~ docker run -d -p 3301:3306 -v /etc/mysql/conf.d -v /var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 --name mysql01 mysql:5.7 2e20d35d29b85d7474d7e6c873db800022dcbf1f0a5f2a2402309691f354672a ➜ ~ docker ps|grep mysql01 2e20d35d29b8 mysql:5.7 "docker-entrypoint.s…" 13 seconds ago Up 11 seconds 33060/tcp, 0.0.0.0:3301->3306/tcp, :::3301->3306/tcp mysql01 # mysql02 ➜ ~ docker run -d -p 3302:3306 -e MYSQL_ROOT_PASSWORD=123456 --name mysql02 --volumes-from mysql01 mysql:5.7 b6804fef3d73dd9648e35a18345d2dc654f6bf607f3aea1d274fe6d9edd720ba ➜ ~ docker ps|grep mysql02 b6804fef3d73 mysql:5.7 "docker-entrypoint.s…" 7 seconds ago Up 5 seconds 33060/tcp, 0.0.0.0:3302->3306/tcp, :::3302->3306/tcp mysql02 ➜ ~- 容器之间配置信息传递，数据卷容器生命周期一直持续到没有容器使用为止。但是一旦持久化到了宿主机，那么永远不会删除。
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