sh - 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 file and placed it in /etc/profile.d, but when I start the container using docker run -it [my_container] sh, my aliases aren't active. I have to manually type . /etc/profile from the command line each time.

Is there some other configuration necessary to get /etc/profile to run at login? I've also had problems with using a ~/.profile file. Any insight is appreciated!

EDIT:

Based on VonC's answer, I pulled and ran his example ruby container. Here is what I got:

$ docker run --rm --name ruby -it codeclimate/alpine-ruby:b42
/ # more /etc/profile.d/rubygems.sh
export PATH=$PATH:/usr/lib/ruby/gems/2.0.0/bin
/ # env
no_proxy=*.local, 169.254/16
HOSTNAME=6c7e93ebc5a1
SHLVL=1
HOME=/root
TERM=xterm
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
/ # exit

Although the /etc/profile.d/rubygems.sh file exists, it is not being run when I login and my PATH environment variable is not being updated. Am I using the wrong docker run command? Is something else missing? Has anyone gotten ~/.profile or /etc/profile.d/ files to work with Alpine on Docker? Thanks!

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