I am trying to use one Dockerfile for both my production and development. The only difference between the production and development are the environment variables I set. Therefore I would like someway import the environment variables from a file. Before using Docker I would simply do the following
. ./setvars
./main.py
However if change ./main.py with the Docker equivalent
. ./setvars
docker run .... ./main.py
then the variables will be on the host and not accessible from the Docker instance. Of course a quick and dirty hack would be to make a file with
#!/bin/bash
. ./setvars
./main.py
and run that in the instance. That would however be really annoying, since I got lots of scripts I would like to run (with the same environment variables), and would then have to create a extra script for everyone of those.
Are there any other solution to get my environment variables inside docker without using a different Dockerfile and the method I described above?
Your best options is to use either the -e flag, or the --env-file of the docker run command.
The -e flag allows you to specify key/value pairs of env variable,
for example:
docker run -e ENVIRONMENT=PROD
You can use several time the -e flag to define multiple env
variables. For example, the docker registry itself is configurable
with -e flags, see:
https://docs.docker.com/registry/deploying/#running-a-domain-registry
The --env-file allow you to specify a file. But each line of the file
must be of type VAR=VAL
Full documentation:
https://docs.docker.com/engine/reference/commandline/run/#set-environment-variables-e-env-env-file
Related
Using the docker run command, I'm trying to pass my NEPTUNE_API_TOKEN to my container.
My understanding is that I should use the -e flag as follows: -e ENV_VAR='env_var_value' and that might work.
I wish, however, to use the value existing in the already-running session, as follows:
docker run -e NEPTUNE_API_TOKEN=$(NEPTUNE_API_TOKEN) <my_image>
However, after doing so, NEPTUNE_API_TOKEN is set to empty when checking the value inside the container.
My question is whether I'm doing something wrong or if this is not possible and I must provide an explicit Neptune API token as a string.
$(NEPTUNE_API_TOKEN) is the syntax for running a command and grabbing the output. Use $NEPTUNE_API_TOKEN.
You can set up and pass NEPTUNE_API_TOKEN as a:
Docker run command options environment variable
Example: docker run -e NEPTUNE_API_TOKEN="<YOUR_API_TOKEN>" <image-name>
Dockerfile environment variable
Docker secret
Neptune will work with any of the methods described above.
For your case, I believe using method 2 and 3 will work best as you will set the API token only once and all containers can reuse it. Additionally, they are more secure methods.
You can read this guide on how to use Neptune with Docker I created last year.
Docs: https://docs.neptune.ai/how-to-guides/automation-pipelines/how-to-use-neptune-with-docker
I'm building an image that is based on an ubuntu image with systemd. I need to start
TigerVNC as a service which depends on some environment variables that I have defined in my
Dockerfile, like the password.
FROM ubuntu-systemd
ENV VNC_PW="some-password"
ENTRYPOINT ["/lib/systemd/systemd"]
The unit file for this service has a line that is:
ExecStart=/usr/sbin/runuser -l root -c "/some/script.sh"
Since systemd has its own environment, I don't have access to the environment variables
defined in my Dockerfile. I was expecting that running the script as root with
a login shell (the '-l' flag) would give me access to these variables but it does not.
I know the variables I need are in /proc/1/environ but I don't know how to load them, for
example adding something in the .profile file for root.
Thank you.
A little bit tricky but I can load the environment variables in the /some/script.sh in the ExecStart property by including the following line:
export `xargs --null --max-args=1 echo < /proc/1/environ`
I'm working on a dotnet core docker container (not aspnet), I'd like to specify configuration options for it through appsettings.json. These values will eventually be filled in through environment variables in kubernetes.
However, for local development, how do we easily pass in these settings without storing them in the container?
You can map local volumes to docker -v local_path:container_path.
If you gonna use kubernetes you can use ConfigMap as well.
You can pass env variables while running the container with -e flag of the command docker run.
With this method, you’ll have to pass each variable in the command line. For example, docker run -e VAR1=value1 -e VAR2=value2
If this gets cumbersome, you can write these values to an env file and use this file like so, docker run --env-file=filename
For reference, you can check out the official docs.
Currently my run command looks like this...
docker run -e DB_URL=$DB_URL -e DB_PORT=$DB_PORT ... <image name>
This works but not very scalable. Is there a way to just pass all configured env vars to the container without declaring each one?
I am using OSX and these are set in a .bash_profile.
env > envFile && docker run --env-file=envFile alpine env
However I would not recommend doing this as this will pass even un-necessary info to docker container.
And you should rather use a compose file or maybe even a simple script to only pass in variables that are actually needed.
This might even mess with the shell inside of a container for things like prompts and locales etc.
Ultimately, the best option is to explicitly list the vars you want to pass. There should only be a finite number of them, they shouldnt change often, and this solution is more robust and more secure.
Note that you can simplify your example. If you want to pass in a defined var with its current value, just name the var instead of setting it:
docker run -e DB_URL -e DB_PORT ... <image name>
I've created a docker image for my database server and one for the web application. Using the documentation I'm able to link between both container using the environment variables as follow:
value="jdbc:postgresql://${DB_PORT_5432_TCP_ADDR}:${DB_PORT_5432_TCP_PORT}/db_name"
It works fine now but it would be better that the environment variables are more general and without containing a static port number. Something like:
value="jdbc:postgresql://${DB_URL}:${DB_PORT}/db_name"
Is there anyway to link between the environment variables? for example by using the ENV command in the dockerfile ENV DB_URL=$DB_PORT_5432_TCP_ADDR or by using the argument --env by running the image docker run ... -e DB_URL=$DB_PORT_5432_TCP_ADDR docker_image ?
Without building this kind of functionality into your docker startup shell scripts or other orchestration mechanism, this is not possible at the moment to create environment variables like you are describing here. You do mention a couple of workarounds. However, the problem at least with using the -e DB_URL=... in your docker run command is that your $DB_PORT_5432_TCP_ADDR environment variable is not known at runtime, and so you will not be able to set this value when you run it. Typically, this is what your orchestration layer is used for, service discovery and passing this kind of data among your containers. There is at least one workaround mentioned here on SO that involves constructing a special shell script that you put in your CMD or ENTRYPOINT directives that passes the environment variable to the container.