docker容器增加端口映射最佳实践（修改配置文件方式）
前言：
在日常的docker运维中，经常遇到这样一个问题：已经配置好且运行的docker容器要根据业务需要增加端口映射到宿主机，如何简单有效的解决呢？
下面以mysql容器为例，详细说明操作步骤。
一、环境准备：
# cat /etc/redhat-release
CentOS Linux release 7.7.1908 (Core)
# docker --version
Docker version 17.09.1-ce, build 19e2cf6
docker-ce 安装说明
1、彻底卸载docker命令（如有安装）
# yum -y remove docker docker-common docker-selinux docker-engine
2、添加yum源
# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
Loaded plugins: fastestmirror, langpacks
adding repo from: https://download.docker.com/linux/centos/docker-ce.repo
grabbing file https://download.docker.com/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo
3、查看版本列表
# yum list docker-ce --showduplicates | sort -r
* updates: mirrors.aliyun.com
Loading mirror speeds from cached hostfile
Loaded plugins: fastestmirror, langpacks
* extras: mirrors.163.com
docker-ce.x86_64 3:19.03.5-3.el7 docker-ce-stable
docker-ce.x86_64 3:19.03.4-3.el7 docker-ce-stable
docker-ce.x86_64 3:19.03.3-3.el7 docker-ce-stable
docker-ce.x86_64 3:19.03.2-3.el7 docker-ce-stable
docker-ce.x86_64 3:19.03.1-3.el7 docker-ce-stable
docker-ce.x86_64 3:19.03.0-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.9-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.8-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.7-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.6-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.5-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.4-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.3-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.2-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.1-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.0-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.3.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.2.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.1.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.0.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 18.03.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.3.ce-1.el7 docker-ce-stable
docker-ce.x86_64 17.03.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.0.ce-1.el7.centos docker-ce-stable
* base: mirrors.aliyun.com
Available Packages
[root@centos7-2 ~]#
4、安装指定版本
# yum -y install yum install docker-ce-17.09.1.ce
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
* base: mirrors.zju.edu.cn
* extras: mirrors.ustc.edu.cn
* updates: mirrors.cqu.edu.cn
Resolving Dependencies
--> Running transaction check
---> Package docker-ce.x86_64 0:17.09.1.ce-1.el7.centos will be installed
--> Processing Dependency: container-selinux >= 2.9 for package: docker-ce-17.09.1.ce-1.el7.centos.x86_64
--> Running transaction check
---> Package container-selinux.noarch 2:2.107-3.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================================================================================================================================================================================================
Package Arch Version Repository Size
================================================================================================================================================================================================================================================================
Installing:
docker-ce x86_64 17.09.1.ce-1.el7.centos docker-ce-stable 21 M
Installing for dependencies:
container-selinux noarch 2:2.107-3.el7 extras 39 k
Transaction Summary
================================================================================================================================================================================================================================================================
Install 1 Package (+1 Dependent package)
Total download size: 21 M
Installed size: 21 M
Is this ok [y/d/N]: y
Downloading packages:
(1/2): container-selinux-2.107-3.el7.noarch.rpm | 39 kB 00:00:00
docker-ce-17.09.1.ce-1.el7.cen FAILED 4% [==== ] 6.1 B/s | 888 kB 967:27:44 ETA
https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: [Errno 12] Timeout on https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
docker-ce-17.09.1.ce-1.el7.cen FAILED 28% [============================= ] 290 B/s | 6.0 MB 15:14:31 ETA
https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: [Errno 12] Timeout on https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
docker-ce-17.09.1.ce-1.el7.cen FAILED 43% [============================================- ] 179 B/s | 9.2 MB 19:30:22 ETA
https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: [Errno 12] Timeout on https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
docker-ce-17.09.1.ce-1.el7.cen FAILED 59% [============================================================= ] 264 B/s | 13 MB 09:29:11 ETA
https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: [Errno 12] Timeout on https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
(2/2): docker-ce-17.09.1.ce-1.el7.centos.x86_64.rpm | 21 MB 00:00:06
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 99 kB/s | 21 MB 00:03:37
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : 2:container-selinux-2.107-3.el7.noarch 1/2
setsebool: SELinux is disabled.
Installing : docker-ce-17.09.1.ce-1.el7.centos.x86_64 2/2
Verifying : docker-ce-17.09.1.ce-1.el7.centos.x86_64 1/2
Verifying : 2:container-selinux-2.107-3.el7.noarch 2/2
Installed:
docker-ce.x86_64 0:17.09.1.ce-1.el7.centos
Dependency Installed:
container-selinux.noarch 2:2.107-3.el7
Complete!
二、建立容器：
1、查看mysql镜像列表
# docker search mysql
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
mysql MySQL is a widely used, open-source relati... 9013 [OK]
mariadb MariaDB is a community-developed fork of M... 3184 [OK]
mysql/mysql-server Optimized MySQL Server Docker images. Crea... 671 [OK]
centos/mysql-57-centos7 MySQL 5.7 SQL database server 67
centurylink/mysql Image containing mysql. Optimized to be li... 61 [OK]
mysql/mysql-cluster Experimental MySQL Cluster Docker images. ... 59
deitch/mysql-backup REPLACED! Please use http://hub.docker.com... 41 [OK]
bitnami/mysql Bitnami MySQL Docker Image 35 [OK]
tutum/mysql Base docker image to run a MySQL database ... 34
schickling/mysql-backup-s3 Backup MySQL to S3 (supports periodic back... 28 [OK]
prom/mysqld-exporter 24 [OK]
linuxserver/mysql A Mysql container, brought to you by Linux... 24
centos/mysql-56-centos7 MySQL 5.6 SQL database server 17
circleci/mysql MySQL is a widely used, open-source relati... 16
mysql/mysql-router MySQL Router provides transparent routing ... 14
arey/mysql-client Run a MySQL client from a docker container 13 [OK]
openshift/mysql-55-centos7 DEPRECATED: A Centos7 based MySQL v5.5 ima... 6
yloeffler/mysql-backup This image runs mysqldump to backup data u... 6 [OK]
genschsa/mysql-employees MySQL Employee Sample Database 4 [OK]
fradelg/mysql-cron-backup MySQL/MariaDB database backup using cron t... 4 [OK]
devilbox/mysql Retagged MySQL, MariaDB and PerconaDB offi... 2
ansibleplaybookbundle/mysql-apb An APB which deploys RHSCL MySQL 2 [OK]
jelastic/mysql An image of the MySQL database server main... 1
monasca/mysql-init A minimal decoupled init container for mysql 0
widdpim/mysql-client Dockerized MySQL Client (5.7) including Cu... 0 [OK]
2、拉取指定镜像
# docker pull mysql:5.6
5.6: Pulling from library/mysql
804555ee0376: Pull complete
c53bab458734: Pull complete
ca9d72777f90: Pull complete
2d7aad6cb96e: Pull complete
8d6ca35c7908: Pull complete
dfc42a380610: Pull complete
fea6d62a8576: Pull complete
f59b0c57b762: Pull complete
aa66d796007b: Pull complete
6ac072c882e7: Pull complete
35f5014f1a5a: Pull complete
Digest: sha256:82a505551c0243ca04df445f1287b2c4da3b23463b1a9c0bc2b2476760179950
Status: Downloaded newer image for mysql:5.6
# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
mysql 5.6 f7ba8643e01a 11 days ago 302MB
3、通过镜像建立容器
这里我们只映射宿主机8080端口到docker容器的80端口
# docker run -it -d --restart always --name mysql-01 -e MYSQL_ROOT_PASSWORD=123456 -p 8080:80 f7ba8643e01a
ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92
查看容器状态
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ce265106bd99 f7ba8643e01a "docker-entrypoint..." 3 seconds ago Up 2 seconds 3306/tcp, 0.0.0.0:8080->80/tcp mysql-01
到这里，我们的环境已经搭建完成，接下来我们就要为容器增加3306 mysql服务器的端口映射
三、增加端口映射：
现在我们来通过修改docker容器的配置文件实现端口映射，文件路径为 /var/lib/docker/containers/容器id
本人环境下的实际路径为：
/var/lib/docker/containers/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92
# cd /var/lib/docker/containers/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92
# ll
total 64
-rw-r----- 1 root root 38507 Jan 9 16:38 ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92-json.log
drwx------ 2 root root 6 Jan 9 16:36 checkpoints
-rw------- 1 root root 2923 Jan 9 16:38 config.v2.json
-rw-r--r-- 1 root root 1199 Jan 9 16:38 hostconfig.json
-rw-r--r-- 1 root root 13 Jan 9 16:36 hostname
-rw-r--r-- 1 root root 174 Jan 9 16:36 hosts
-rw-r--r-- 1 root root 82 Jan 9 16:36 resolv.conf
-rw-r--r-- 1 root root 71 Jan 9 16:36 resolv.conf.hash
drwx------ 2 root root 6 Jan 9 16:36 shm
这里可以看到有两个json文件：
hostconfig.json—— 配置宿主机和docker容器的端口映射关系
{"Binds":null,"ContainerIDFile":"","LogConfig":{"Type":"json-file","Config":{}},"NetworkMode":"default","PortBindings":{"80/tcp":[{"HostIp":"","HostPort":"8080"}],"3306/tcp":[{"HostIp":"","HostPort":"3506"}]},"RestartPolicy":{"Name":"always","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}
config.v2.json —— docker容器的端口
{"StreamConfig":{},"State":{"Running":false,"Paused":false,"Restarting":false,"OOMKilled":false,"RemovalInProgress":false,"Dead":false,"Pid":0,"ExitCode":0,"Error":"","StartedAt":"2020-01-09T08:36:14.519441922Z","FinishedAt":"2020-01-09T08:38:39.994812777Z","Health":null},"ID":"ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92","Created":"2020-01-09T08:36:14.149947925Z","Managed":false,"Path":"docker-entrypoint.sh","Args":["mysqld"],"Config":{"Hostname":"ce265106bd99","Domainname":"","User":"","AttachStdin":false,"AttachStdout":false,"AttachStderr":false,"ExposedPorts":{"3306/tcp":{},"80/tcp":{}},"Tty":true,"OpenStdin":true,"StdinOnce":false,"Env":["MYSQL_ROOT_PASSWORD=123456","PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","GOSU_VERSION=1.7","MYSQL_MAJOR=5.6","MYSQL_VERSION=5.6.46-1debian9"],"Cmd":["mysqld"],"ArgsEscaped":true,"Image":"f7ba8643e01a","Volumes":{"/var/lib/mysql":{}},"WorkingDir":"","Entrypoint":["docker-entrypoint.sh"],"OnBuild":null,"Labels":{}},"Image":"sha256:f7ba8643e01a1b582ffcf90cd5eab5ba97af396703ce9b6e2e292f6bbacd1d04","NetworkSettings":{"Bridge":"","SandboxID":"261f828c8935a0398c3f63cdef17c3bee413a3bb3ac924f3d57f36d4d644860e","HairpinMode":false,"LinkLocalIPv6Address":"","LinkLocalIPv6PrefixLen":0,"Networks":{"bridge":{"IPAMConfig":null,"Links":null,"Aliases":null,"NetworkID":"c10113ebd3a94dfae806c32f17ad37bdd6538ba24584dce63dda3c457b16cea5","EndpointID":"","Gateway":"","IPAddress":"","IPPrefixLen":0,"IPv6Gateway":"","GlobalIPv6Address":"","GlobalIPv6PrefixLen":0,"MacAddress":"","DriverOpts":null,"IPAMOperational":false}},"Service":null,"Ports":null,"SandboxKey":"/var/run/docker/netns/261f828c8935","SecondaryIPAddresses":null,"SecondaryIPv6Addresses":null,"IsAnonymousEndpoint":false,"HasSwarmEndpoint":false},"LogPath":"/var/lib/docker/containers/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92-json.log","Name":"/mysql-01","Driver":"overlay","Platform":"linux","MountLabel":"","ProcessLabel":"","RestartCount":0,"HasBeenStartedBefore":true,"HasBeenManuallyStopped":false,"MountPoints":{"/var/lib/mysql":{"Source":"","Destination":"/var/lib/mysql","RW":true,"Name":"7bac0015730f3eef9b3cb326b3c56c3eb0ae540938165a3c2d3c6e0b92dfe375","Driver":"local","Type":"volume","Spec":{}}},"SecretReferences":null,"ConfigReferences":null,"AppArmorProfile":"","HostnamePath":"/var/lib/docker/containers/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92/hostname","HostsPath":"/var/lib/docker/containers/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92/hosts","ShmPath":"/var/lib/docker/containers/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92/shm","ResolvConfPath":"/var/lib/docker/containers/ce265106bd99eb19cbc7f30db811cbcbc3de9bf0976e23fbaad65cb0e7e6ba92/resolv.conf","SeccompProfile":"","NoNewPrivileges":false}
【注意】修改容器的配置文件之前，一定要停掉docker服务
#service docker stop
在 hostconfig.json 里有 “PortBindings”:{} 这个配置项，可以改成 “PortBindings”:{“80/tcp”:[{“HostIp”:"",“HostPort”:“8080”}],“3306/tcp”:[{“HostIp”:"",“HostPort”:“3506”}]}, 黄色部分为增加内容，这里 3306 是容器端口， 3506是宿主机端口；
在 config.v2.json 里面 “ExposedPorts”:{“3306/tcp”:{},“80/tcp”:{}},“Tty”:true 容器已经开启了3306端口，不用增加；
修改完成后，启动docker服务
# service docker start
Redirecting to /bin/systemctl start docker.service
查看容器，可以看到3306端口已经映射到了主机的3506上
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ce265106bd99 f7ba8643e01a "docker-entrypoint..." 6 minutes ago Up 4 seconds 0.0.0.0:8080->80/tcp, 0.0.0.0:3506->3306/tcp mysql-01
通过mysql客户端连接测试正常，说明端口映射成功！
2020.01.10 周五下班前 深圳南山