如何将环境变量传递给Docker容器？ [英] How do I pass environment variables to Docker containers?

问题描述

我是Docker的新手，目前还不清楚如何从容器访问外部数据库。是连接字符串中最好的硬编码方式吗？

I'm new to Docker, and it's unclear how to access an external database from a container. Is the best way to hard-code in the connection string?

# Dockerfile
ENV DATABASE_URL amazon:rds/connection?string

推荐答案

您可以将环境变量传递到容器中

You can pass environment variables to your containers with the -e flag.

启动脚本中的一个示例：

An example from a startup script:

sudo docker run -d -t -i -e REDIS_NAMESPACE='staging' \ 
-e POSTGRES_ENV_POSTGRES_PASSWORD='foo' \
-e POSTGRES_ENV_POSTGRES_USER='bar' \
-e POSTGRES_ENV_DB_NAME='mysite_staging' \
-e POSTGRES_PORT_5432_TCP_ADDR='docker-db-1.hidden.us-east-1.rds.amazonaws.com' \
-e SITE_URL='staging.mysite.com' \
-p 80:80 \
--link redis:redis \  
--name container_name dockerhub_id/image_name

或者，如果您不想在命令行上具有该值它将由 ps 显示等等， -e 可以从当前环境中提取值，如果您只是在没有 = 的情况下提供该值：

Or, if you don't want to have the value on the command-line where it will be displayed by ps, etc., -e can pull in the value from the current environment if you just give it without the =:

sudo PASSWORD='foo' docker run  [...] -e PASSWORD [...]

如果你有很多环境变量，特别是如果它们是秘密的，你可以使用环境文件：

If you have many environment variables and especially if they're meant to be secret, you can use an env-file:

$ docker run --env-file ./env.list ubuntu bash

--env-file标志将一个文件名作为参数，并期望每行都是VAR = VAL格式，模仿参数传递给--env。评论行只需要加上＃

The --env-file flag takes a filename as an argument and expects each line to be in the VAR=VAL format, mimicking the argument passed to --env. Comment lines need only be prefixed with #

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