Unified Configuration File Setup Across Multiple Machines – Revisited

My last post discussed how to get your config files, known as “dotfiles,” synchronized across multiple machines using a rudimentary makefile and git. I said that I hoped of achieving the “one folder for all config files” dream. I have achieved it, and it is pretty simple. Also, I will discuss how to handle files with passwords in them, and some other thoughts on this setup.

Keep track of system files, too

Essentially, my last post left out all but the system configuration files, such as /etc/fstab and the like. The /etc folder is owned by root, as well as the /boot folder. My first approach was to simply replace all such files with more symlinks, which would point to files owned by the normal user of the system. This approach had its drawbacks: (1) not all system files are symlinkable (e.g., /etc/sudoers is particularly security-conscious), and (2) the idea of deleting system files and replacing them with symlinks, on its face, sounded like I was setting myself up for a big grand screw-up.

So I thought: “Well, since system files are seldom ever edited anyway, why not just back them up periodically?” And that’s what I did instead. Now my makefile, as discussed in the previous post, has a section like this:

# copy contents of system files to keep track of them
syscopy:
ifeq ('$(HOSTNAME)','exelion')
	cat /boot/grub/menu.lst >       /home/shinobu/syscfg/sys/boot-grub-menu.lst-exelion
	cat /etc/X11/xorg.conf >        /home/shinobu/syscfg/sys/etc-X11-xorg.conf-exelion
	cat /etc/fstab >                /home/shinobu/syscfg/sys/etc-fstab-exelion
	cat /etc/hosts >                /home/shinobu/syscfg/sys/etc-hosts-exelion
	cat /etc/inittab >              /home/shinobu/syscfg/sys/etc-inittab-exelion
	cat /etc/makepkg.conf >         /home/shinobu/syscfg/sys/etc-makepkg.conf-exelion
	cat /etc/rc.conf >              /home/shinobu/syscfg/sys/etc-rc.conf-exelion
	cat /etc/rc.local >             /home/shinobu/syscfg/sys/etc-rc.local-exelion
	cat /etc/rc.local.shutdown >    /home/shinobu/syscfg/sys/etc-rc.local.shutdown-exelion
	cat /etc/yaourtrc >             /home/shinobu/syscfg/sys/etc-yaourtrc-exelion
	cat /etc/sudoers >              /home/shinobu/syscfg/sys/etc-sudoers-exelion # requires superuser privileges to read!
else
	cat /boot/grub/menu.lst >       /home/shinobu2/syscfg/sys/boot-grub-menu.lst-luxion
	cat /etc/X11/xorg.conf >        /home/shinobu2/syscfg/sys/etc-X11-xorg.conf-luxion
	cat /etc/fstab >                /home/shinobu2/syscfg/sys/etc-fstab-luxion
	cat /etc/hosts >                /home/shinobu2/syscfg/sys/etc-hosts-luxion
	cat /etc/inittab >              /home/shinobu2/syscfg/sys/etc-inittab-luxion
	cat /etc/makepkg.conf >         /home/shinobu2/syscfg/sys/etc-makepkg.conf-luxion
	cat /etc/network.d/luxion-wired > /home/shinobu2/syscfg/sys/etc-network.d-luxion-wired
	cat /etc/network.d/luxion-wireless-home-nopassword > /home/shinobu2/syscfg/sys/etc-network.d-luxion-wireless-home-nopassword
	cat /etc/rc.conf >              /home/shinobu2/syscfg/sys/etc-rc.conf-luxion
	cat /etc/rc.local >             /home/shinobu2/syscfg/sys/etc-rc.local-luxion
	cat /etc/rc.local.shutdown >    /home/shinobu2/syscfg/sys/etc-rc.local.shutdown-luxion
	cat /etc/yaourtrc >             /home/shinobu2/syscfg/sys/etc-yaourtrc-luxion
	cat /etc/sudoers >              /home/shinobu2/syscfg/sys/etc-sudoers-luxion
endif

I have in my /etc/rc.local the command “make -f /path/to/the/above/makefile -B syscopy“. So every time my system boots up, all of the config files are copied into their backup-equivalents in the syscfg/sys folder. Since git tracks changes in the syscfg folder, only changes in the config files are detected and tracked as changes (i.e., git doesn’t track changes in file modification times, which is a good thing here for our purposes — otherwise git would be saying that every time we boot up all of our system files have changed!). So now all of my system config files are tracked passively (by merely reading off them). Of course, if I manually edit a system file, I can still call make -B syscopy myself manually, and then run git diff in the syscfg folder to track those changes, and then git commit to solidify those changes into the git history.

For config files with passwords in them

DO NOT EVER PUT CONFIG FILES WITH PASSWORDS INTO YOUR TRACKED DOTFILES FOLDER! Not only does this mean that your password, in plain text, is tracked by git, but that should you ever change your password, git will notice the changes and track them as well! This will give anyone who gets access to your git repo a complete, timestamped history of your passwords for your applications (like icecast, irssi, etc.) So to get around this problem, I have it set up so that I have a copy of the password-containing config file, minus the passwords in them. Whenever I make changes to the original password-containing files, I update the changes into the copies, and then track these copies in git, not the originals.

Not all config files need symlinks

In my last post, I discussed how creating symlinks via commands in the makefile was the key to this whole setup. But for some (smarter) applications, symlinks are not needed, since they can intelligently be told which config file to use. Alpine, icecast, irssi, and mpd are like this, so I just have config files for them inside my syscfg folder, and just run these apps (which are all autostarted for me each time on boot) with commandline parameters pointing to the non-default config file locations.

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