docker容器数据卷

什么是容器数据卷

需求：我们在容器中运行mysql服务. 怎么做到容器销毁我们的数据不丢失 实现数据的持久化

猜想： 我们要是能够将我们的数据 存储到我们的容器的宿主机上这样我们就不担心我们的数据丢失了（物理故障除外）

技术实现： 数据卷技术就能实现这个需求

使用数据卷

1.直接使用数据卷

docker run -it -v 主机目录:容器目录

[root@localhost ~]# docker run -d -it --name=centos05 -v /root/test:/home/ centos
95c671f317f397e996177282559fea96b86698283c45c5d3806dca7ec5f40194
[root@localhost ~]# docker inspect centos05

测试文件同步:

1、宿主机操作文件容器同步操作

2、容器操作宿主机同步

3.关闭容器测试：

我们能惊奇的发现数据的同步哪怕容器处于关闭的状态也是可以同步的

实战： mysql数据持久化

1.安装MySQL数据库
docker run -d -p 3310:3306 -v /home/mysql/conf:/etc/mysql/conf.d -v /home/mysql/data:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 --name mysql01 m
ysql:5.7
Unable to find image 'mysql:5.7' locally
5.7: Pulling from library/mysql
d121f8d1c412: Already exists 
f3cebc0b4691: Already exists 
1862755a0b37: Already exists 
489b44f3dbb4: Already exists 
690874f836db: Already exists 
baa8be383ffb: Already exists 
55356608b4ac: Already exists 
277d8f888368: Pull complete 
21f2da6feb67: Pull complete 
2c98f818bcb9: Pull complete 
031b0a770162: Pull complete 
Digest: sha256:14fd47ec8724954b63d1a236d2299b8da25c9bbb8eacc739bb88038d82da4919
Status: Downloaded newer image for mysql:5.7
0b80fee1e472fa46f234cc02c04a7bf62f8466bcecb219c4bc1ef4ee5c8acb33

2.查看我们宿主机目录 看看是否有我们的mysql数据
[root@localhost mysql]# pwd
/home/mysql
[root@localhost mysql]# ls
conf  data
[root@localhost mysql]# cd data/
[root@localhost data]# ls
auto.cnf    ca.pem           client-key.pem  ibdata1      ib_logfile1  mysql               private_key.pem  server-cert.pem  sys
ca-key.pem  client-cert.pem  ib_buffer_pool  ib_logfile0  ibtmp1       performance_schema  public_key.pem   server-key.pem
[root@localhost data]# 

3.删除docker 容器
[root@localhost data]# docker ps 
CONTAINER ID        IMAGE                    COMMAND                  CREATED             STATUS              PORTS                               NAMES
0b80fee1e472        mysql:5.7                "docker-entrypoint.s…"   6 minutes ago       Up 6 minutes        33060/tcp, 0.0.0.0:3310->3306/tcp   mysql01
[root@localhost data]# docker rm -f mysql01
mysql01
[root@localhost data]# docker ps 
CONTAINER ID        IMAGE                    COMMAND                  CREATED             STATUS              PORTS                              NAMES
4.我们的数据文件是否还在
[root@localhost data]# ls
auto.cnf    ca.pem           client-key.pem  ibdata1      ib_logfile1  mysql               private_key.pem  server-cert.pem  sys
ca-key.pem  client-cert.pem  ib_buffer_pool  ib_logfile0  ibtmp1       performance_schema  public_key.pem   server-key.pem   test

5.我们的持久化存储实现

那么想这样的挂载有几种呢？

匿名挂载和具名挂载

# 匿名挂载
-v 容器内路径
root@localhost ~]# docker run -d -it --name=Nginx01 -v /etc/nginx nginx
[root@localhost ~]# docker inspect Nginx01
				....
"Mounts": [
            {
                "Type": "volume",
                "Name": "0eef256e6a4c6ef5e0b2e5376294e25d498b5caba98733f7ce5641add15bdfb5",
                "Source": "/var/lib/docker/volumes/0eef256e6a4c6ef5e0b2e5376294e25d498b5caba98733f7ce5641add15bdfb5/_data",
                "Destination": "/etc/nginx",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }
         .....
 # 查看所有卷的情况
[root@localhost ~]# docker volume ls
DRIVER              VOLUME NAME
local               0eef256e6a4c6ef5e0b2e5376294e25d498b5caba98733f7ce5641add15bdfb5
local               00d9a09b3f3bf62352e563ee6fbd191c13af9939d58974f11c2d98a1cc832f99
local               25702591833c4618d78e2fc32598437a1c388f787210846d14ceb6eb5ab88cb7

#具名挂载

-v 挂载卷名:容器内路径

[root@localhost ~]# docker run  -d -it --name=Nginx02 -P -v Nginx-conf:/etc/nginx nginx
[root@localhost ~]# docker ps 
CONTAINER ID        IMAGE                    COMMAND                  CREATED             STATUS              PORTS                              NAMES
a87e394c3794        nginx                    "/docker-entrypoint.…"   5 seconds ago       Up 4 seconds        0.0.0.0:32768->80/tcp              Nginx02
fbfb104587c9        nginx                    "/docker-entrypoint.…"   9 minutes ago       Up 9 minutes        80/tcp                             Nginx01
[root@localhost ~]# docker volume ls
DRIVER              VOLUME NAME
local               0eef256e6a4c6ef5e0b2e5376294e25d498b5caba98733f7ce5641add15bdfb5
local               00d9a09b3f3bf62352e563ee6fbd191c13af9939d58974f11c2d98a1cc832f99
local               25702591833c4618d78e2fc32598437a1c388f787210846d14ceb6eb5ab88cb7
local               Nginx-conf

#查看数据卷详细信息

[root@localhost ~]# docker volume inspect Nginx-conf
[
    {
        "CreatedAt": "2020-09-10T12:46:44+08:00",
        "Driver": "local",
        "Labels": null,
        "Mountpoint": "/var/lib/docker/volumes/Nginx-conf/_data",
        "Name": "Nginx-conf",
        "Options": null,
        "Scope": "local"
    }
]

#加上前面说的指定目录挂载 总共三种方法

挂载卷是否有权限限制？有哪几种？

拓展：

# 默认是 rw
# ro 只要看到ro就说明这个路径只能通过宿主机来操作，容器内部是无法操作！

# 通过 -v 容器内路径：ro 或 rw   改变读写权限
# 一旦创建容器时设置了容器权限，容器对我们挂载出来的内容就有限定了！
docker run -d -P --name nginx05 -v Nginx-conf:/etc/nginx:ro nginx
docker run -d -P --name nginx05 -v Nginx-conf:/etc/nginx:rw nginx

数据卷之dockerFIle

初识DockerFile

什么是dockerfile?

Dockerfile是一个文本文档，其中包含用户可以在命令行上调用以组合图像的所有命令。使用docker build 用户可以创建一个自动执行的构建，该构建可以连续执行多个命令行指令。

Dockerfile 就是用来构建 docker镜像的构建文件！命令脚本！ 先体验一下！

通过这个脚本可以生成镜像，镜像是一层一层的，脚本是一个个的命令，每个命令都是最终镜像的一层！

实战：dockerfile匿名挂载数据卷

#1.创建dockerfile文件
[root@localhost volume]# cat dockerfile 
FROM centos

VOLUME ["volume01","volume02"]

CMD  echo"-----------build secccessful!---------"

CMD  /bin/bash

#2.build dockerfile
[root@localhost volume]# docker build -f dockerfile -t martin/centos-volume . 
Sending build context to Docker daemon  2.048kB
Step 1/4 : FROM centos
 ---> 0d120b6ccaa8
Step 2/4 : VOLUME ["volume01","volume02"]
 ---> Running in 08bd38fc2b20
Removing intermediate container 08bd38fc2b20
 ---> 5373c024b9bd
Step 3/4 : CMD  echo"-----------build secccessful!---------"
 ---> Running in 47e69c382a92
Removing intermediate container 47e69c382a92
 ---> 5294966f9a51
Step 4/4 : CMD  /bin/bash
 ---> Running in 6b63ec9c5d91
Removing intermediate container 6b63ec9c5d91
 ---> 0080b2fa0c13
Successfully built 0080b2fa0c13
Successfully tagged martin/centos-volume:latest
#3查看镜像
[root@localhost volume]# docker images
REPOSITORY               TAG                 IMAGE ID            CREATED                  SIZE
martin/centos-volume     latest              0080b2fa0c13        18 seconds ago           215MB
martin/tomcat02          0.1                 75448ab28707        2 hours ago              652MB
#4以新生成的镜像创建容器
[root@localhost volume]# docker run -d -it --name=test-dof-vol martin/centos-volume
38452f2db864f1c0136cb63021af8b66ac1dfae29ab0c451479b85840a6f7637
[root@localhost volume]# docker ps
CONTAINER ID        IMAGE                    COMMAND                  CREATED             STATUS              PORTS                              NAMES
38452f2db864        martin/centos-volume     "/bin/sh -c /bin/bash"   8 seconds ago       Up 7 seconds                                           test-dof-vol
5.查看和测试数据卷
[root@localhost volume]# docker inspect test-dof-vol
 "Mounts": [
            {
                "Type": "volume",
                "Name": "d577c8ff3c360963159e3631d2c307a1a44ce068c2888b167b035e527bb4005b",
                "Source": "/var/lib/docker/volumes/d577c8ff3c360963159e3631d2c307a1a44ce068c2888b167b035e527bb4005b/_data",
                "Destination": "volume01",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            },
            {
                "Type": "volume",
                "Name": "0745d3159fe5295f1262c872a487614c563147aadcb2ec519f449817f3804521",
                "Source": "/var/lib/docker/volumes/0745d3159fe5295f1262c872a487614c563147aadcb2ec519f449817f3804521/_data",
                "Destination": "volume02",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }

测试：

数据卷容器

需求： 多个容器同步数据

#数据卷容器
 在启动容器是 使用 --volumes-from 容器id|容器名    #会将容器id的数据卷作为数据容器挂载到新的容
 #启动容docker01 作为容器卷
 [root@localhost _data]# docker run -d -it --name=docker01 martin/centos-volume
 [root@localhost _data]# docker inspect docker01
 "Mounts": [
            {
                "Type": "volume",
                "Name": "d5c127e77ae816374681bab51f1319e4935d593d20f6a94f7267473727786fc9",
                "Source": "/var/lib/docker/volumes/d5c127e77ae816374681bab51f1319e4935d593d20f6a94f7267473727786fc9/_data",
                "Destination": "volume01",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            },
            {
                "Type": "volume",
                "Name": "4e64fa0f86a8080c25a92829f70f1350b6c6a7ac75cd0d877b14ed04ac6d9dbd",
                "Source": "/var/lib/docker/volumes/4e64fa0f86a8080c25a92829f70f1350b6c6a7ac75cd0d877b14ed04ac6d9dbd/_data",
                "Destination": "volume02",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }
        ]
#启动dcoker02 以docker01 为容器卷启动
[root@localhost _data]# docker run -d -it --name=docker02 --volumes-from docker01 centos 
a4006a8881b55527db8fb50dec272dbd5670b923a70a9eadc951300a003fce77
[root@localhost _data]# docker inspect docker02
"Mounts": [
            {
                "Type": "volume",
                "Name": "d5c127e77ae816374681bab51f1319e4935d593d20f6a94f7267473727786fc9",
                "Source": "/var/lib/docker/volumes/d5c127e77ae816374681bab51f1319e4935d593d20f6a94f7267473727786fc9/_data",
                "Destination": "volume01",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            },
            {
                "Type": "volume",
                "Name": "4e64fa0f86a8080c25a92829f70f1350b6c6a7ac75cd0d877b14ed04ac6d9dbd",
                "Source": "/var/lib/docker/volumes/4e64fa0f86a8080c25a92829f70f1350b6c6a7ac75cd0d877b14ed04ac6d9dbd/_data",
                "Destination": "volume02",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }
        ]
#我们发现容器docker02 数据卷是用共享了docker01的数据卷

#以docker01为数据容器启动docker03
[root@localhost _data]# docker run -d -it --name=docker03 --volumes-from docker01 centos 
9bdb00a12f91300d841f2c26d621f2126c509887af4c9554beaefe60c8062123

docker03 也是共享了docker01的数据卷 此处不板书了 接下来我们测试

测试

1.在数据卷中创建和删除文件看是否同步

2.分别在容器中创建和删除文件文件看是否同步

3.删除docker01 看数据卷是否还能生效

结论 容器只是一种复制容器卷的卷的挂载关系 只要数据存在 我们的映射关系就不会失效