8.容器数据卷
2023-11-19 本文已影响0人
_FireFly_
什么是容器数据卷？
docker的理念回顾
将应用环境打包成一个镜像！
数据该怎么处理？如果数据都在容器中，那么我们在删除容器的时候，数据也会被删除丢失。
此时需要找到一个数据可以持久化的办法
Mysql容器删了，删库跑路？ 需求：Mysql数据可以存储在本地
容器之间可以有一个数据共享的技术，Dokcer容器中产生的数据，同步到本地。
这种技术就是卷技术，也就是目录的挂载，将我们容器内的目录，挂载在linux上面。
目录的挂载
总结一句话：容器的持久化和同步操作，容器之间也是可以数据共享的。
使用数据卷
方式一：直接使用命令来挂载 -v
直接使用命令来挂载 -v
运行centos
docker run -it -v /home/ceshi:/home centos /bin/bash
#-v: linux上的home文件夹下的ceshi文件 与docker镜像中的home文件进行映射挂载
# 此时俩个文件夹内容只要有一方进行修改，另一方相应也会发生同样的变化
运行centos
查看镜像上的/home文件的内容
查看镜像上的/home文件的内容
查看linux上的/home/ceshi内容
查看linux上的/home/ceshi内容
查看docker容器中的centos镜像元数据
docker inspect 4b919874be24
[root@localhost ~]# docker inspect 4b919874be24
[
{
"Id": "4b919874be24d51856fdeb447c19956a51765f6a44f5f0c992916713699044c5",
"Created": "2023-11-19T01:52:42.173286272Z",
"Path": "/bin/bash",
"Args": [],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 1896,
"ExitCode": 0,
"Error": "",
"StartedAt": "2023-11-19T01:52:43.149374434Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:5d0da3dc976460b72c77d94c8a1ad043720b0416bfc16c52c45d4847e53fadb6",
"ResolvConfPath": "/var/lib/docker/containers/4b919874be24d51856fdeb447c19956a51765f6a44f5f0c992916713699044c5/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/4b919874be24d51856fdeb447c19956a51765f6a44f5f0c992916713699044c5/hostname",
"HostsPath": "/var/lib/docker/containers/4b919874be24d51856fdeb447c19956a51765f6a44f5f0c992916713699044c5/hosts",
"LogPath": "/var/lib/docker/containers/4b919874be24d51856fdeb447c19956a51765f6a44f5f0c992916713699044c5/4b919874be24d51856fdeb447c19956a51765f6a44f5f0c992916713699044c5-json.log",
"Name": "/amazing_mclaren",
"RestartCount": 0,
"Driver": "overlay2",
"Platform": "linux",
"MountLabel": "",
"ProcessLabel": "",
"AppArmorProfile": "",
"ExecIDs": null,
"HostConfig": {
"Binds": [
"/home/ceshi:/home"
],
"ContainerIDFile": "",
"LogConfig": {
"Type": "json-file",
"Config": {}
},
"NetworkMode": "default",
"PortBindings": {},
"RestartPolicy": {
"Name": "no",
"MaximumRetryCount": 0
},
"AutoRemove": false,
"VolumeDriver": "",
"VolumesFrom": null,
"ConsoleSize": [
46,
193
],
"CapAdd": null,
"CapDrop": null,
"CgroupnsMode": "host",
"Dns": [],
"DnsOptions": [],
"DnsSearch": [],
"ExtraHosts": null,
"GroupAdd": null,
"IpcMode": "private",
"Cgroup": "",
"Links": null,
"OomScoreAdj": 0,
"PidMode": "",
"Privileged": false,
"PublishAllPorts": false,
"ReadonlyRootfs": false,
"SecurityOpt": null,
"UTSMode": "",
"UsernsMode": "",
"ShmSize": 67108864,
"Runtime": "runc",
"Isolation": "",
"CpuShares": 0,
"Memory": 0,
"NanoCpus": 0,
"CgroupParent": "",
"BlkioWeight": 0,
"BlkioWeightDevice": [],
"BlkioDeviceReadBps": [],
"BlkioDeviceWriteBps": [],
"BlkioDeviceReadIOps": [],
"BlkioDeviceWriteIOps": [],
"CpuPeriod": 0,
"CpuQuota": 0,
"CpuRealtimePeriod": 0,
"CpuRealtimeRuntime": 0,
"CpusetCpus": "",
"CpusetMems": "",
"Devices": [],
"DeviceCgroupRules": null,
"DeviceRequests": null,
"MemoryReservation": 0,
"MemorySwap": 0,
"MemorySwappiness": null,
"OomKillDisable": false,
"PidsLimit": null,
"Ulimits": null,
"CpuCount": 0,
"CpuPercent": 0,
"IOMaximumIOps": 0,
"IOMaximumBandwidth": 0,
"MaskedPaths": [
"/proc/asound",
"/proc/acpi",
"/proc/kcore",
"/proc/keys",
"/proc/latency_stats",
"/proc/timer_list",
"/proc/timer_stats",
"/proc/sched_debug",
"/proc/scsi",
"/sys/firmware",
"/sys/devices/virtual/powercap"
],
"ReadonlyPaths": [
"/proc/bus",
"/proc/fs",
"/proc/irq",
"/proc/sys",
"/proc/sysrq-trigger"
]
},
"GraphDriver": {
"Data": {
"LowerDir": "/var/lib/docker/overlay2/b87a1127a509c3f9ca414a897987fc4720b3c0ab534fe64bfed840439727bc39-init/diff:/var/lib/docker/overlay2/5e980180ea2e6be0c4f4ebaa8e21ef829533f1ae28c06f68c285590ac4de71a7/diff",
"MergedDir": "/var/lib/docker/overlay2/b87a1127a509c3f9ca414a897987fc4720b3c0ab534fe64bfed840439727bc39/merged",
"UpperDir": "/var/lib/docker/overlay2/b87a1127a509c3f9ca414a897987fc4720b3c0ab534fe64bfed840439727bc39/diff",
"WorkDir": "/var/lib/docker/overlay2/b87a1127a509c3f9ca414a897987fc4720b3c0ab534fe64bfed840439727bc39/work"
},
"Name": "overlay2"
},
"Mounts": [
{
"Type": "bind",
"Source": "/home/ceshi",
"Destination": "/home",
"Mode": "",
"RW": true,
"Propagation": "rprivate"
}
],
"Config": {
"Hostname": "4b919874be24",
"Domainname": "",
"User": "",
"AttachStdin": true,
"AttachStdout": true,
"AttachStderr": true,
"Tty": true,
"OpenStdin": true,
"StdinOnce": true,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"/bin/bash"
],
"Image": "centos",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": {
"org.label-schema.build-date": "20210915",
"org.label-schema.license": "GPLv2",
"org.label-schema.name": "CentOS Base Image",
"org.label-schema.schema-version": "1.0",
"org.label-schema.vendor": "CentOS"
}
},
"NetworkSettings": {
"Bridge": "",
"SandboxID": "85394b339d65ff82203c7b7e67247282479aac87562a2a45e15ec73bec735ab2",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {},
"SandboxKey": "/var/run/docker/netns/85394b339d65",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "285ad0cc1ec17789278ac4113497e419b2e40d07a7f49e2bed51eb5dbe33ff32",
"Gateway": "172.17.0.1",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"IPAddress": "172.17.0.2",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"MacAddress": "02:42:ac:11:00:02",
"Networks": {
"bridge": {
"IPAMConfig": null,
"Links": null,
"Aliases": null,
"NetworkID": "d6032c8a10557b37a95ab87aa418a86226166852796e189e4e2880f901955b26",
"EndpointID": "285ad0cc1ec17789278ac4113497e419b2e40d07a7f49e2bed51eb5dbe33ff32",
"Gateway": "172.17.0.1",
"IPAddress": "172.17.0.2",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "02:42:ac:11:00:02",
"DriverOpts": null
}
}
}
}
]
查看docker容器中的centos镜像元数据
查看docker容器中的centos镜像元数据的挂载对应详情
在docker容器中，退出容器 Ctrl +P+Q ：退出窗口 容器继续运行不进行关闭
exit命令：退出窗口 容器停止运行关闭
在docker容器中，退出容器 Ctrl +P+Q
在linux系统中，进入正在运行的docker容器命令
docker exec -it 4b919874be24 /bin/bash
在linux系统中，进入正在运行的docker容器命令
进入容器中的home目录下
进入容器中的home目录下
测试查看同步情况
测试将docker容器停止，在linux上的home/ceshi文件进行修改，发现即使docker容器停止，文件也可以进行同步
解决linux找不到vim命令
linux中的test.java
在linux中的test.java中进行编写
docker attach 4b919874be24 #进入正在运行的命令行
进入正在运行的命令行
查看docker中的home目录下的test.java,发现内容同步成功
结论：我们以后修改只需要在本地修改即可，容器内会自动进行同步~~~
具名挂载和匿名挂载
匿名挂载
-v 容器内路径
使用匿名挂载方式运行nginx
docker run -d -P --name nginx01 -v /etc/nginx nginx
#-P：随机映射端口
#不指定本地位置 直接-v
#只指定了容器内位置 没有指定容器外地址
查看本地所有的卷的情况
docker volume ls #查看所有volume的情况
查看本地所有的卷的情况
匿名卷挂载
具名方式运行nginx
docker run -d -P --name nginx02 -v juming-nginx:/etc/nginx nginx
具名方式运行nginx
此时查看卷 里面有了juming-nginx卷名字
此时查看卷
查看具体数据卷的位置
docker volume inspect juming-nginx
查看具体数据卷的位置
查看具体数据卷的位置
所有的docker容器内的卷的位置
image.png
进入docker的工作目录
[root@localhost /]# cd /var/lib/docker
[root@localhost docker]# ls
进入docker的工作目录
所有docker卷的实际位置
查看juming-nginx卷的内容 发现已经把nginx的配置文件全部都复制过来了
[root@localhost /]# cd /var/lib/docker
[root@localhost docker]# ls
buildkit containers engine-id image network overlay2 plugins runtimes swarm tmp volumes
[root@localhost docker]# cd volumes/
[root@localhost volumes]# ls
584f53911411f2f38e1f19647310868e7faff28c7c227daca2554560783994ab backingFsBlockDev juming-nginx metadata.db
[root@localhost volumes]# cd juming-nginx/
[root@localhost juming-nginx]# ls
_data
[root@localhost juming-nginx]# cd _data/
[root@localhost _data]# ls
conf.d fastcgi_params mime.types modules nginx.conf scgi_params uwsgi_params
查看juming-nginx卷的内容 发现已经把nginx的配置文件全部都复制过来了
具名挂载、匿名挂载、指定路径的挂载 三种挂载的说明
具名挂载、匿名挂载、指定路径的挂载 三种挂载的说明
扩展
多个mysql同步数据
同步原理
运行docker01
docker run -it --name docker01 guobaofeng/centos:1.0
运行docker01
运行docker01
再运行一个docker02 然后通过--volumes-from命令让它同步docker01
docker run -it --name docker02 --volumes-from docker01 guobaofeng/centos:1.0
docker02
再次进入docker01容器
docker attach c7326450eeda
再次进入docker01容器
查看docker02的volume01文件
--volumes-from命令解释
--volumes-from命令解释
再次启动一个docker03也挂在docker01上
docker run -it --name docker03 --volumes-from docker01 guobaofeng/centos:1.0
在docker03的volume01文件夹中再touch一个docker03文件，看看docker01和docker02是否也可以同步创建docker03
在docker03的volume01文件夹中再touch一个docker03文件，看看docker01和docker02是否也可以同步创建docker03
查看docker01的volume01文件夹下是否有docker03
查看docker01的volume01文件夹下是否有docker03
--volumes-from解释
--volumes-from解释
移除docker01 ，查看docker02和docker03的同步是否受影响
docker rm -f c7326450eeda
再次查看docker03的volume01文件，发现虽然docker01移除了，但是docker03的volume01依旧存在
再次查看docker03的volume01文件，发现虽然docker01移除了，但是docker03的volume01依旧存在
--volumes-from 拷贝的概念
多个mysql实现数据共享
结论
