How to get /etc/profile to run automatically in Alpine / Docker

Question

How can I get /etc/profile to run automatically when starting an Alpine Docker container interactively? I have added some aliases to an aliases.sh

Answer 1

The default shell in Alpine Linux is ash.

Ash will only read the /etc/profile and ~/.profile files if it is started as a login shell sh -l.

To force Ash to source the /etc/profile or any other script you want upon its invocation as a non login shell, you need to setup an environment variable called ENV before launching Ash.

e.g. in your Dockerfile

FROM alpine:3.5

ENV ENV="/root/.ashrc"

RUN echo "echo 'Hello, world!'" > "$ENV"

When you build that you get:

deployer@ubuntu-1604-amd64:~/blah$ docker build --tag test .
Sending build context to Docker daemon  2.048kB
Step 1/3 : FROM alpine:3.5
3.5: Pulling from library/alpine
627beaf3eaaf: Pull complete
Digest: sha256:58e1a1bb75db1b5a24a462dd5e2915277ea06438c3f105138f97eb53149673c4
Status: Downloaded newer image for alpine:3.5
 ---> 4a415e366388
Step 2/3 : ENV ENV "/root/.ashrc"
 ---> Running in a9b6ff7303c2
 ---> 8d4af0b7839d
Removing intermediate container a9b6ff7303c2
Step 3/3 : RUN echo "echo 'Hello, world!'" > "$ENV"
 ---> Running in 57c2fd3353f3
 ---> 2cee6e034546
Removing intermediate container 57c2fd3353f3
Successfully built 2cee6e034546

Finally, when you run the newly generated container, you get:

deployer@ubuntu-1604-amd64:~/blah$ docker run -ti test /bin/sh
Hello, world!
/ # exit

Notice the Ash shell didn't run as a login shell.

So to answer your query, replace

ENV ENV="/root/.ashrc"

with:

ENV ENV="/etc/profile"

and Alpine Linux's Ash shell will automatically source the /etc/profile script each time the shell is launched.

Gotcha: /etc/profile is normally meant to only be sourced once! So, I would advise that you don't source it and instead source a /root/.somercfile instead.

Source: https://stackoverflow.com/a/40538356