概念：有点类似我们 Redis 里面的 rdb 和 aof 文件

先来看看 Docker 的理念：

将运用与运行的环境打包形成容器运行，运行可以伴随着容器，但是我们对数据的要求希望是持久化的
容器之间希望有可能共享数据

一容器数据卷的作用

卷就是目录或文件，存在于一个或多个容器中，由 docker 挂载到容器，但不属于联合文件系统，因此能够绕过 Union File System 提供一些用于持续存储或共享数据的特性：

卷的设计目的就是数据的持久化，完全独立于容器的生存周期，因此 Docker 不会在容器删除时删除其挂载的数据卷

特点：

1：数据卷可在容器之间共享或重用数据
2：卷中的更改可以直接生效
3：数据卷中的更改不会包含在镜像的更新中
4：数据卷的生命周期一直持续到没有容器使用它为止

总结

容器持久 hua4
容器间继承
数据共享

二添加数据卷

2.1 通过命令添加

添加命令如下

docker run -it -v /宿主机的绝对路径目录:/容器内目录 镜像名

在主机上执行如下命令:

yishui@yishui:~$ docker images 
REPOSITORY           TAG                 IMAGE ID            CREATED             SIZE
yishui/tomcat-demo   1.0                 1323b27a2652        2 hours ago         463MB
<none>               <none>              7cfe70fc34b0        2 hours ago         463MB
tomcat               latest              168588387c68        3 weeks ago         463MB
centos               latest              1e1148e4cc2c        2 months ago        202MB
yishui@yishui:~$ docker run -it -v /home/yishui/桌面/demo:/dataContainer centos
[root@34e873f8dc2b /]# ls
anaconda-post.log  bin  dataContainer  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
[root@34e873f8dc2b /]#

可以看到，本地路径已经被挂在进入了。

2.2 查看数据卷是否挂载成功

yishui@yishui:~$ docker ps 
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
34e873f8dc2b        centos              "/bin/bash"         10 minutes ago      Up 10 minutes                           upbeat_leavitt
yishui@yishui:~$ 
yishui@yishui:~$ docker inspect 34e873f8dc2b
[
    {
        "Id": "34e873f8dc2b2dfb5eb6c759bea5e37282003d6ff45743d5c10a769acba170df",
        "Created": "2019-03-02T14:41:25.607089707Z",
        "Path": "/bin/bash",
        "Args": [],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 8845,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2019-03-02T14:41:27.06209462Z",
            "FinishedAt": "0001-01-01T00:00:00Z"
        },
        "Image": "sha256:1e1148e4cc2c148c6890a18e3b2d2dde41a6745ceb4e5fe94a923d811bf82ddb",
        "ResolvConfPath": "/var/lib/docker/containers/34e873f8dc2b2dfb5eb6c759bea5e37282003d6ff45743d5c10a769acba170df/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/34e873f8dc2b2dfb5eb6c759bea5e37282003d6ff45743d5c10a769acba170df/hostname",
        "HostsPath": "/var/lib/docker/containers/34e873f8dc2b2dfb5eb6c759bea5e37282003d6ff45743d5c10a769acba170df/hosts",
        "LogPath": "/var/lib/docker/containers/34e873f8dc2b2dfb5eb6c759bea5e37282003d6ff45743d5c10a769acba170df/34e873f8dc2b2dfb5eb6c759bea5e37282003d6ff45743d5c10a769acba170df-json.log",
        "Name": "/upbeat_leavitt",
        "RestartCount": 0,
        "Driver": "overlay2",
        "Platform": "linux",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "docker-default",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": [
                "/home/yishui/桌面/demo:/dataContainer"
            ],
            "ContainerIDFile": "",
            "LogConfig": {
                "Type": "json-file",
                "Config": {}
            },
            "NetworkMode": "default",
            "PortBindings": {},
            "RestartPolicy": {
                "Name": "no",
                "MaximumRetryCount": 0
            },
            "AutoRemove": false,
            "VolumeDriver": "",
            "VolumesFrom": null,
            "CapAdd": null,
            "CapDrop": null,
            "Dns": [],
            "DnsOptions": [],
            "DnsSearch": [],
            "ExtraHosts": null,
            "GroupAdd": null,
            "IpcMode": "shareable",
            "Cgroup": "",
            "Links": null,
            "OomScoreAdj": 0,
            "PidMode": "",
            "Privileged": false,
            "PublishAllPorts": false,
            "ReadonlyRootfs": false,
            "SecurityOpt": null,
            "UTSMode": "",
            "UsernsMode": "",
            "ShmSize": 67108864,
            "Runtime": "runc",
            "ConsoleSize": [
                0,
                0
            ],
            "Isolation": "",
            "CpuShares": 0,
            "Memory": 0,
            "NanoCpus": 0,
            "CgroupParent": "",
            "BlkioWeight": 0,
            "BlkioWeightDevice": [],
            "BlkioDeviceReadBps": null,
            "BlkioDeviceWriteBps": null,
            "BlkioDeviceReadIOps": null,
            "BlkioDeviceWriteIOps": null,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "Devices": [],
            "DeviceCgroupRules": null,
            "DiskQuota": 0,
            "KernelMemory": 0,
            "MemoryReservation": 0,
            "MemorySwap": 0,
            "MemorySwappiness": null,
            "OomKillDisable": false,
            "PidsLimit": 0,
            "Ulimits": null,
            "CpuCount": 0,
            "CpuPercent": 0,
            "IOMaximumIOps": 0,
            "IOMaximumBandwidth": 0,
            "MaskedPaths": [
                "/proc/acpi",
                "/proc/kcore",
                "/proc/keys",
                "/proc/latency_stats",
                "/proc/timer_list",
                "/proc/timer_stats",
                "/proc/sched_debug",
                "/proc/scsi",
                "/sys/firmware"
            ],
            "ReadonlyPaths": [
                "/proc/asound",
                "/proc/bus",
                "/proc/fs",
                "/proc/irq",
                "/proc/sys",
                "/proc/sysrq-trigger"
            ]
        },
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/6c2a4ebd1bbe8f6dedc2f074cdde310377e2d9d20be637b9c9a89f7b678d236c-init/diff:/var/lib/docker/overlay2/ff665c5429b28f49965818bdfb616377723719f87ae79ba0fb5c42bdffa87bcf/diff",
                "MergedDir": "/var/lib/docker/overlay2/6c2a4ebd1bbe8f6dedc2f074cdde310377e2d9d20be637b9c9a89f7b678d236c/merged",
                "UpperDir": "/var/lib/docker/overlay2/6c2a4ebd1bbe8f6dedc2f074cdde310377e2d9d20be637b9c9a89f7b678d236c/diff",
                "WorkDir": "/var/lib/docker/overlay2/6c2a4ebd1bbe8f6dedc2f074cdde310377e2d9d20be637b9c9a89f7b678d236c/work"
            },
            "Name": "overlay2"
        },
        "Mounts": [
            {
                "Type": "bind",
                "Source": "/home/yishui/桌面/demo",
                "Destination": "/dataContainer",
                "Mode": "",
                "RW": true,
                "Propagation": "rprivate"
            }
        ],
        "Config": {
            "Hostname": "34e873f8dc2b",
            "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"
            ],
            "ArgsEscaped": true,
            "Image": "centos",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "org.label-schema.build-date": "20181205",
                "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": "9f7f7afba32a3ebd87864c133a755efdbbd5d19edcd57188cd7c3f587931653f",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {},
            "SandboxKey": "/var/run/docker/netns/9f7f7afba32a",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "e2242781e120de2e769a368c7a6182b3db7ed4b73d4da79e39066371809e0a26",
            "Gateway": "172.17.0.1",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "172.17.0.3",
            "IPPrefixLen": 16,
            "IPv6Gateway": "",
            "MacAddress": "02:42:ac:11:00:03",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "2d6916d345929f6d9d83583bcab801903d0061620c1b4669699eb7a7bfd61462",
                    "EndpointID": "e2242781e120de2e769a368c7a6182b3db7ed4b73d4da79e39066371809e0a26",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.3",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:03",
                    "DriverOpts": null
                }
            }
        }
    }
]
yishui@yishui:~$

HostConfig 下面的 Binds 节点表明已经挂载成功。(也可以看 Mounts 节点)

容器停止退出后，修改主机数据，再次进入容器，数据依旧同步

2.3 带权限启动

docker run -it -v /宿主机的绝对路径目录:/容器内目录:ro 镜像名

2.4 通过 DockerFile 添加

tomcat 的官方 DockerFile 示例文件

#
# NOTE: THIS DOCKERFILE IS GENERATED VIA "apply-templates.sh"
#
# PLEASE DO NOT EDIT IT DIRECTLY.
#

FROM openjdk:8-jre-buster

ENV CATALINA_HOME /usr/local/tomcat
ENV PATH $CATALINA_HOME/bin:$PATH
RUN mkdir -p "$CATALINA_HOME"
WORKDIR $CATALINA_HOME

# let "Tomcat Native" live somewhere isolated
ENV TOMCAT_NATIVE_LIBDIR $CATALINA_HOME/native-jni-lib
ENV LD_LIBRARY_PATH ${LD_LIBRARY_PATH:+$LD_LIBRARY_PATH:}$TOMCAT_NATIVE_LIBDIR

# see https://www.apache.org/dist/tomcat/tomcat-9/KEYS
# see also "versions.sh" (https://github.com/docker-library/tomcat/blob/master/versions.sh)
ENV GPG_KEYS 48F8E69F6390C9F25CFEDCD268248959359E722B A9C5DF4D22E99998D9875A5110C01C5A2F6059E7 DCFD35E0BF8CA7344752DE8B6FB21E8933C60243

ENV TOMCAT_MAJOR 9
ENV TOMCAT_VERSION 9.0.58
ENV TOMCAT_SHA512 33c030a312a0a087deeb06fff921d13a23789e152d30620f33a368e7a2244c762fcf9acd55f3b90f08560704ba45bc2be820bccf2058b0cf5801a7b124f9056d

COPY --from=tomcat:9.0.58-jdk8-openjdk-buster $CATALINA_HOME $CATALINA_HOME
RUN set -eux; \
	apt-get update; \
	xargs -rt apt-get install -y --no-install-recommends < "$TOMCAT_NATIVE_LIBDIR/.dependencies.txt"; \
	rm -rf /var/lib/apt/lists/*

# verify Tomcat Native is working properly
RUN set -eux; \
	nativeLines="$(catalina.sh configtest 2>&1)"; \
	nativeLines="$(echo "$nativeLines" | grep 'Apache Tomcat Native')"; \
	nativeLines="$(echo "$nativeLines" | sort -u)"; \
	if ! echo "$nativeLines" | grep -E 'INFO: Loaded( APR based)? Apache Tomcat Native library' >&2; then \
		echo >&2 "$nativeLines"; \
		exit 1; \
	fi

EXPOSE 8080
CMD ["catalina.sh", "run"]

在宿主机上操作:

根目录下新建 demo 文件夹并进入
可在 Dockerfile 中使用 VOLUME 指令 来给镜像添加一个或多个数据卷

命令如下：

VOLUME["/dataVolumeContainer","/dataVolumeContainer2","/dataVolumeContainer3"]

说明：
出于可移植和分享的考虑，用-v 主机目录:容器目录这种方法不能够直接在 Dockerfile 中实现。

由于宿主机目录是依赖于特定宿主机的，并不能够保证在所有的宿主机上都存在这样的特定目录。

文件内容如下:

# volume test
FROM centos
VOLUME ["/containerPath1","/containerPath2"]
CMD echo "完成===========》"
CMD /bin/bash

build 后生成镜像(获得一个新镜像)

命令如下

docker build -f /demo/dockerFile_demo yishui_dockerFile/centos

启动新生成的容器

2.5 获取映射路径

此时，可以通过

docker inspect 容器 Id

获取到 containerPath1，containerPath2 在宿主机上对应的路径

三访问权限报错

Docker 挂载主机目录 Docker 访问出现 cannot open directory .: Permission denied

解决办法：在挂载目录后多加一个—privileged=true 参数即可

四容器数据卷

命名的容器挂载数据卷，其它容器通过挂载这个(父容器)实现数据共享，挂载数据卷的容器，称之为数据卷容器

先启动第一个容器，并将其命名为 doc01
分别启动 doc02 和 doc03 并继承 doc01

docker run -it --name doc02 --volumes-from doc01 yishui_demo/centos

结论：容器之间配置信息的传递，数据卷的生命周期一直持续到没有容器使用它为止

docker入门之数据卷

docker进阶知识---docker数据卷和容器数据卷详解

一容器数据卷的作用

二添加数据卷

2.1 通过命令添加

2.2 查看数据卷是否挂载成功

2.3 带权限启动

2.4 通过 DockerFile 添加

2.5 获取映射路径

三访问权限报错

四容器数据卷

FEATURED TAGS

FRIENDS

一 容器数据卷的作用

二 添加数据卷

2.1 通过命令添加

2.2 查看数据卷是否挂载成功

2.3 带权限启动

2.4 通过 DockerFile 添加

2.5 获取映射路径

三 访问权限报错

四 容器数据卷

FEATURED TAGS

FRIENDS

一容器数据卷的作用

二添加数据卷

三访问权限报错

四容器数据卷