码头构成端口映射

我有一个 docker-compose yml 文件，如下所示

version: '2'
services:
nodejs:
build:
context: .
dockerfile: DockerFile
ports:
- "4000:4000"
links:
- redis
expose:
- "6379"
redis:
build:
context: .
dockerfile: Dockerfile-redis

我的目标是将 nodejs-127.0.0.1端口6379转发到 redis 主机。我已经可以从 nodejs 机器 ping redis，但是端口没有映射。试过暴露选项，但也没有机会。

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小开

If you want to access redis from the host (127.0.0.1), you have to use the ports command.

redis:
build:
context: .
dockerfile: Dockerfile-redis
ports:
- "6379:6379"
小开

If you want to bind to the redis port from your nodejs container you will have to expose that port in the redis container:

version: '2'
services:
nodejs:
build:
context: .
dockerfile: DockerFile
ports:
- "4000:4000"
links:
- redis


redis:
build:
context: .
dockerfile: Dockerfile-redis
expose:
- "6379"

The expose tag will let you expose ports without publishing them to the host machine, but they will be exposed to the containers networks.

https://docs.docker.com/compose/compose-file/#expose

The ports tag will be mapping the host port with the container port HOST:CONTAINER

https://docs.docker.com/compose/compose-file/#ports

小开

It's important to point out that all of the above solutions map the port to every interface on your machine. This is less than desirable if you have a public IP address, or your machine has an IP on a large network. Your application may be exposed to a much wider audience than you'd hoped.

redis:
build:
context:
dockerfile: Dockerfile-redis
ports:
- "127.0.0.1:3901:3901"

127.0.0.1 is the ip address that maps to the hostname localhost on your machine. So now your application is only exposed over that interface and since 127.0.0.1 is only accessible via your machine, you're not exposing your containers to the entire world.

The documentation explains this further and can be found here: https://docs.docker.com/compose/compose-file/#ports

Note: If you're using Docker for mac this will make the container listen on 127.0.0.1 on the Docker for Mac VM and will not be accessible from your localhost. If I recall correctly.

小开

It seems like the other answers here all misunderstood your question. If I understand correctly, you want to make requests to localhost:6379 (the default for redis) and have them be forwarded, automatically, to the same port on your redis container.

https://unix.stackexchange.com/a/101906/38639 helped me get to the right answer.

First, you'll need to install the nc command on your image. On CentOS, this package is called nmap-ncat, so in the example below, just replace this with the appropriate package if you are using a different OS as your base image.

Next, you'll need to tell it to run a certain command each time the container boots up. You can do this using CMD.

# Add this to your Dockerfile
RUN yum install -y --setopt=skip_missing_names_on_install=False nmap-ncat
COPY cmd.sh /usr/local/bin/cmd.sh
RUN chmod +x /usr/local/bin/cmd.sh
CMD ["/usr/local/bin/cmd.sh"]

Finally, we'll need to set up port-forwarding in cmd.sh. I found that nc, even with the -l and -k options, will occasionally terminate when a request is completed, so I'm using a while-loop to ensure that it's always running.

# cmd.sh
#! /usr/bin/env bash


while nc -l -p 6379 -k -c "nc redis 6379" || true; do true; done &


tail -f /dev/null # Or any other command that never exits

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