How to change the mapped port in docker

1. Edit the configuration file of the container to change the port;

docker run 运行启动时  -p 可以指定容器启动映射端口 （0.0.0.0:18080 8080）

You can edit the configuration file to make changes; (You need to restart the docker service to take effect, not just the container. Only It will still be overwritten if you can restart the container)

2. Find the container that needs to change the port

docker ps

3. Find the docker configuration file according to the CONTAINER ID; (Container The file configuration defaults to /var/lib/docker/containers)

Because I changed the default storage location of docker. (Docker info can view docker information)

4. Change the docker default environment variable. The default configuration is /var/lib/docker

Add the default environment system configuration in the docker startup file" / etc/default/docker ":

Add Environment File configuration:

# vi /usr/lib/systemd/system/docker.service

Add under [Serivce]

EnvironmentFile=-/etc/default/docker #添加配置文件

Add under [Install]

EnvironmentFile=-/etc/default/docker

(Recommended tutorial: docker tutorial)

5. Stop the container

docker stop [ID/name]

6. Stop the docker service

systemctl stop docker

7 . Edit and change the container's configuration file hostconfig.json

config.v2.json. You will only see the mapped address when the container is started, so there is no need to do this.

/data/docker/containers/0731470143a94579b837b295f4c03a5f283e2bc1b0be746e7da451b9eb817120/hostconfig.json
容器配置命名就是 以 CONTAINER ID 容器ID开头的

8. View and edit the hostconfig.json file;

jq . ./hostconfig.json
# jq 查看json 格式文件
# 更改 HostPort 就是映射的宿主机端口。

9. Start the docker service to start the container

docker start [ID/NAME]
systemctl start docker 
docker ps

10. Start the container , iptables will be added automatically; just run server iptables save directly. Or if you are not worried, you can add the port directly:

宿主机添加端口:
iptables -A INPUT -p tcp -m state --state NEW -m tcp --dport 58080 -j ACCEPT

宿主机 nat 映射:
iptables -A DOCKER ! -i docker0 -p tcp -m tcp --dport 58080 -j DNAT --to-destination 172.16.4.3:8080

Note:

When docker operates or adds a container, first service iptables save, then edit and add restart.

Adding a container will add mapping to the firewall by default, but it will become invalid after restarting iptables, so you need to save it first and then restart it.

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