How to pass environment variables to a Docker container?

Question

I’ve seen this being asked quite a bit, so I’ve decided to write this answer outlining a few ways how to pass environment variables to a Docker container.

Hope that this is helpful! If you have any questions post the below!

Bobby · Accepted Answer

Set environment variable with the -e flag The -e flag can be used to pass environment variables to a Docker container. For example, if you want to pass the environment variable MY_ENV_VAR to the container, you can do the following: docker run -e "MY_ENV_VAR=some_value" image-name The -e is short for --env, so you can also use that instead: docker run --env "MY_ENV_VAR=some_value" image-name The -e flag can be used multiple times to pass multiple environment variables: docker run -e "MY_VAR_1=some_value1" -e "MY_VAR_2=some_value2" -e "MY_VAR_3=some_value3" image-name The same can be achieved with docker-compose: docker-compose run -e MY_ENV_VAR=some_value Set environment variable with the --env-file flag If you want to pass a file containing all of your environment variables to a Docker container, you can use the --env-file flag. The --env-file flag allows you to pass a file containing environment variables to a Docker container. Let’s say that you have a .env file containing the following environment variables: MY_ENV_VAR=some_value MY_SECOND_ENV_VAR=some_other_value MY_THIRD_ENV_VAR=yet_another_value Rather than passing the environment variables directly to the container, you can pass the .env file to the container using the --env-file flag: docker run --env-file .env image-name Alternatively, if you are using docker-compose, you can do the same thing: docker-compose --env-file .env up Set environment variable within docker-compose.yml If you are using docker-compose to manage your Docker containers, you can pass environment variables to the container using the environment key in the docker-compose.yml file. For example: version: '3' services: my-container: image: image-name environment: MY_ENV_VAR: some_value MY_SECOND_ENV_VAR: some_other_value MY_THIRD_ENV_VAR: yet_another_value For more information, see the Docker Compose documentation . How Do I Pass Environment Variables to Docker Containers? Hope that this helps!

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How to pass environment variables to a Docker container?

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How to pass environment variables to a Docker container?

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