set environment variable in running docker contianer

Question

I need to set environment variable in a running docker container. I am already aware of the way of setting environment variable while creating a container. As far I found there

Answer 1

I find a way to provide environment variable to a running container. Fist upgrade your docker-engine. I am using V1.12.5.

create a script with environment variables-

#!/bin/bash

echo "export VAR1=VAL1
export VAR2=VAL2" >> /etc/bash.bashrc
source /etc/bash.bashrc

Now start a container. Here, 'test' is the container name:

docker run -idt --name=test ubuntu

Copy your script to container:

docker cp script.sh test:/

Run the script :

docker exec -it test /bin/bash -c "/script.sh"

Restart your container:

docker restart test 

Go to container shell

docker exec -it test /bin/bash

Check the variable

echo $VAR1