Docker数据存储 Docker数据存储默认情况下，在运行中的容器里创建的文件，被保存在一个可写的容器层：如果容器被删除了，则数据也没有了这个可写的容器层是和特定的容器绑定的，也就是这些数据无法方便的和其它容器共享Docker主要提供了两种方式做数据的持久化Data Volume, 由Docker管理，(/var/lib/docker/volumes/ Linux), 持久化数据的最好方式Bind Mount，由用户指定存储的数据具体mount在系统什么位置一、Data Volume环境准备准备一个Dockerfile 和一个 my-cron的文件$ ls Dockerfile my-cron $ more Dockerfile FROM alpine:latest RUN apk update RUN apk --no-cache add curl ENV SUPERCRONIC_URL=https://github.com/aptible/supercronic/releases/download/v0.1.12/supercronic-linux-amd64 \ SUPERCRONIC=supercronic-linux-amd64 \ SUPERCRONIC_SHA1SUM=048b95b48b708983effb2e5c935a1ef8483d9e3e RUN curl -fsSLO "$SUPERCRONIC_URL" \ && echo "${SUPERCRONIC_SHA1SUM} ${SUPERCRONIC}" | sha1sum -c - \ && chmod +x "$SUPERCRONIC" \ && mv "$SUPERCRONIC" "/usr/local/bin/${SUPERCRONIC}" \ && ln -s "/usr/local/bin/${SUPERCRONIC}" /usr/local/bin/supercronic COPY my-cron /app/my-cron WORKDIR /app VOLUME ["/app"] # RUN cron job CMD ["/usr/local/bin/supercronic", "/app/my-cron"] $ $ more my-cron */1 * * * * date >> /app/test.txt构建镜像$ docker image build -t my-cron . $ docker image ls REPOSITORY TAG IMAGE ID CREATED SIZE my-cron latest e9fbd9a562c9 4 seconds ago 24.7MB创建容器(不指定-v参数)此时Docker会自动创建一个随机名字的volume，去存储我们在Dockerfile定义的volume VOLUME ["/app"]$ docker run -d my-cron 9a8fa93f03c42427a498b21ac520660752122e20bcdbf939661646f71d277f8f $ docker volume ls DRIVER VOLUME NAME local 043a196c21202c484c69f2098b6b9ec22b9a9e4e4bb8d4f55a4c3dce13c15264 $ docker volume inspect 043a196c21202c484c69f2098b6b9ec22b9a9e4e4bb8d4f55a4c3dce13c15264 [ { "CreatedAt": "2021-06-22T23:06:13+02:00", "Driver": "local", "Labels": null, "Mountpoint": "/var/lib/docker/volumes/043a196c21202c484c69f2098b6b9ec22b9a9e4e4bb8d4f55a4c3dce13c15264/_data", "Name": "043a196c21202c484c69f2098b6b9ec22b9a9e4e4bb8d4f55a4c3dce13c15264", "Options": null, "Scope": "local" } ]在这个Volume的mountpoint可以发现容器创建的文件。创建容器(指定-v参数)在创建容器的时候通过 -v 参数我们可以手动的指定需要创建Volume的名字，以及对应于容器内的路径，这个路径是可以任意的，不必需要在Dockerfile里通过VOLUME定义。比如我们把上面的Dockerfile里的VOLUME删除FROM alpine:latest RUN apk update RUN apk --no-cache add curl ENV SUPERCRONIC_URL=https://github.com/aptible/supercronic/releases/download/v0.1.12/supercronic-linux-amd64 \ SUPERCRONIC=supercronic-linux-amd64 \ SUPERCRONIC_SHA1SUM=048b95b48b708983effb2e5c935a1ef8483d9e3e RUN curl -fsSLO "$SUPERCRONIC_URL" \ && echo "${SUPERCRONIC_SHA1SUM} ${SUPERCRONIC}" | sha1sum -c - \ && chmod +x "$SUPERCRONIC" \ && mv "$SUPERCRONIC" "/usr/local/bin/${SUPERCRONIC}" \ && ln -s "/usr/local/bin/${SUPERCRONIC}" /usr/local/bin/supercronic COPY my-cron /app/my-cron WORKDIR /app # RUN cron job CMD ["/usr/local/bin/supercronic", "/app/my-cron"]重新build镜像，然后创建容器，加-v参数$ docker image build -t my-cron . $ docker container run -d -v cron-data:/app my-cron 43c6d0357b0893861092a752c61ab01bdfa62ea766d01d2fcb8b3ecb6c88b3de $ docker volume ls DRIVER VOLUME NAME local cron-data $ docker volume inspect cron-data [ { "CreatedAt": "2021-06-22T23:25:02+02:00", "Driver": "local", "Labels": null, "Mountpoint": "/var/lib/docker/volumes/cron-data/_data", "Name": "cron-data", "Options": null, "Scope": "local" } ] $ ls /var/lib/docker/volumes/cron-data/_data my-cron $ ls /var/lib/docker/volumes/cron-data/_data my-cron test.txt环境清理强制删除所有容器，系统清理和volume清理$ docker rm -f $(docker container ps -aq) $ docker system prune -f $ docker volume prune -f二、Bind Mount只需要将-v的data volume换成指定路径即可。windows下的linux就可以直接挂载到磁盘，linx的可以直接查看。例如mysqldocker run -p 3306:3306 --name mysql \ -v /mydata/mysql/log:/var/log/mysql \ -v /mydata/mysql/data:/var/lib/mysql \ -v /mydata/mysql/conf:/etc/mysql \ -e MYSQL_ROOT_PASSWORD=密码 \ -d mysql:5.7-v /mydata/mysql/log:/var/log/mysql这里就是将容器中/var/log/mysql日志，通过Bind Mount持久化到linux主机的/mydata/mysql/log目录。多个机器之间的容器共享数据官方参考链接 https://docs.docker.com/storage/volumes/#share-data-among-machinesDocker的volume支持多种driver。默认创建的volume driver都是local$ docker volume inspect vscode [ { "CreatedAt": "2021-06-23T21:33:57Z", "Driver": "local", "Labels": null, "Mountpoint": "/var/lib/docker/volumes/vscode/_data", "Name": "vscode", "Options": null, "Scope": "local" } ]这一节我们看看一个叫sshfs的driver，如何让docker使用不在同一台机器上的文件系统做volume环境准备准备三台Linux机器，之间可以通过SSH相互通信。hostnameipssh usernamessh passworddocker-host1192.168.200.10vagrantvagrantdocker-host2192.168.200.11vagrantvagrantdocker-host3192.168.200.12vagrantvagrant安装plugin在其中两台机器上安装一个plugin vieux/sshfs[vagrant@docker-host1 ~]$ docker plugin install --grant-all-permissions vieux/sshfs latest: Pulling from vieux/sshfs Digest: sha256:1d3c3e42c12138da5ef7873b97f7f32cf99fb6edde75fa4f0bcf9ed277855811 52d435ada6a4: Complete Installed plugin vieux/sshfs[vagrant@docker-host2 ~]$ docker plugin install --grant-all-permissions vieux/sshfs latest: Pulling from vieux/sshfs Digest: sha256:1d3c3e42c12138da5ef7873b97f7f32cf99fb6edde75fa4f0bcf9ed277855811 52d435ada6a4: Complete Installed plugin vieux/sshfs创建volume[vagrant@docker-host1 ~]$ docker volume create --driver vieux/sshfs \ -o sshcmd=vagrant@192.168.200.12:/home/vagrant \ -o password=vagrant \ sshvolume查看[vagrant@docker-host1 ~]$ docker volume ls DRIVER VOLUME NAME vieux/sshfs:latest sshvolume [vagrant@docker-host1 ~]$ docker volume inspect sshvolume [ { "CreatedAt": "0001-01-01T00:00:00Z", "Driver": "vieux/sshfs:latest", "Labels": {}, "Mountpoint": "/mnt/volumes/f59e848643f73d73a21b881486d55b33", "Name": "sshvolume", "Options": { "password": "vagrant", "sshcmd": "vagrant@192.168.200.12:/home/vagrant" }, "Scope": "local" } ]创建容器挂载Volume创建容器，挂载sshvolume到/app目录，然后进入容器的shell，在/app目录创建一个test.txt文件[vagrant@docker-host1 ~]$ docker run -it -v sshvolume:/app busybox sh Unable to find image 'busybox:latest' locally latest: Pulling from library/busybox b71f96345d44: Pull complete Digest: sha256:930490f97e5b921535c153e0e7110d251134cc4b72bbb8133c6a5065cc68580d Status: Downloaded newer image for busybox:latest / # / # ls app bin dev etc home proc root sys tmp usr var / # cd /app /app # ls /app # echo "this is ssh volume"> test.txt /app # ls test.txt /app # more test.txt this is ssh volume /app # /app #这个文件我们可以在docker-host3上看到[vagrant@docker-host3 ~]$ pwd /home/vagrant [vagrant@docker-host3 ~]$ ls test.txt [vagrant@docker-host3 ~]$ more test.txt this is ssh volume