envrcd

An environment switcher for shared system accounts.

Motivation

An admin is probably more efficient and certainly much happier in his customized environment. That includes settings like aliases, colors, environment variables, program configurations etc. Of course this does not apply for real hacker gurus in front of a green shimmering CRT screen, they just need one color, that is green, and the defaults. But some noob admins, like me, don't even know how to move the cursor if vim is in compatibility mode. With only /root/.bashrc all admins need to agree on a common environment. Nobody will be completely happy. This project tries to solve that problem.

Reserved files in envrcd.d

These files should only exist locally and are ignored by git

• 00-local: ENVRCD_SET_* (contains user settings, exists only in your private home)
• 20-host: ENVRCD_INVENTORY (host specific environment vars, ansible managed)
• 90-host-late: host aliases (host specific alias overrides, ansible managed)
• 95-host-late-local: local only (host specific overrides, locally managed)

00-local: ~/.envrcd/envrcd.d/00-local

Create this file to set local user settings. Only use this in your users home directory. Do not use this file for root.

export ENVRCD_SET_USER="<username>"    # set envrcd user name
export ENVRCD_SET_PROFILE="<profile>"  # set envrcd profile to use (leave empty for default)
export ENVRCD_SET_DEBUG="true"         # enable debugging messages
export ENVRCD_NO_ENVRCD="true"         # abort loading advance envrcd settings, can be used should something go wrong

20-host: ~/.envrcd/envrcd.d/20-host

Create this file to set host specific settings.

export ENVRCD_INVENTORY="testing"      # set inventory group

90-host-late: ~/.envrcd/envrcd.d/90-host-late

Create this file to set host specific settings that should override possible user settings. Useful to define host specific aliases.

Basic operation

The script works by sending environment variables prefixed with ENVRCD_SET_* via SSH to the remote host. The following variables are supported:

• ENVRCD_SET_USER: Set this to your name
• ENVRCD_SET_PROFILE: Profile to load
• ENVRCD_SET_DEBUG: Set to enable debugging mode
• ENVRCD_SET_NOENVRCD: Set to disable advanced user envrcd and load system root defaults

Load order:

• The script first loads its configuration from ~/.envrcd/envrcd.d/
• Then if ENVRCD_SET_PROFILE is set, it will try to load the profile from ~/.envrcd/profile/${ENVRCD_SET_PROFILE}
• If it is unset it will load the defaults from ~/.encrcd/profile/default

All following files are sourced inside the profile directory in this order:

• envrcd
• envrcd.d/*
• .bashrc

To load host specific settings place 20-host and/or 90-host-late in ~/.envrcd/envrcd.d/. For example, we can set ENVRCD_INVENTORY to production or testing in 20-host, which will show a different colored prompt. The default is to assume we are on a production system if this variable is not set.

Configuration for the user (on your workstation)

Send the ENVRCD_SET_* environment vars in either /etc/ssh/ssh_config or ~/.ssh/config:

SendEnv [...] ENVRCD_SET_*

Minimalist variant

Export the following variables in your ~/.bashrc for your normal account:

export ENVRCD_SET_USER="<username>"

Or migrate your ~/.bashrc to envrcd

Setup the files:

cd ~
git clone git@gitlab.phys.ethz.ch:core/envrcd.git .envrcd
mkdir .envrcd/profile/<my_profile>
mv .bashrc .envrcd/profile/<my_profile>/
ln -s .envrcd/.envrcd .bashrc

Create your local ~/.envrcd/envrcd.d/00-local and set ENVRCD_SET_USER and ENVRCD_SET_PROFILE:

export ENVRCD_SET_USER="<username>"
export ENVRCD_SET_PROFILE="<my_profile>"

Commit and push your changes:

cd .envrcd
git add -A
git commit -m 'Add user <username>'
git push

Installation for root (server)

Setup the files:

ssh root@server
git clone git@gitlab.phys.ethz.ch:core/envrcd.git .envrcd
mv .bashrc .bashrc.old
ln -s .envrcd/.envrcd .bashrc

Accept the ENVRCD_SET_* environment vars in /etc/ssh/sshd_config:

AcceptEnv [...] ENVRCD_SET_*

Restart sshd:

systemctl restart sshd