On Sun, 2006-06-11 at 23:39 +0200, Eric Spakman wrote: > Hello list, > > The Bering-uClibc crew is working on a new config/backup system. In this > system config changes are no longer saved in the package itself but in a > seperate "configdb" package. The same is true for modules, which are saved > in a "moddb" package. > > This is done because several users suggested to split the configuration > from the binaries. > > The config system only saves the changed files, keeping the overhead to a > minumum. It is partly based on apkg by Nathan and Nathaneal.
Cool... :-) I guess its mostly Nathans work. > It works as follows (somewhat simplified): > -At startup (pre-init) the sha1-sums of files listed in a <package>.local > file are calculated and saved in a <package>.sha1 file. The files listed > in <package>.local are user changable files like config files and f.e. > ssh-keys > -At backup time the contents of the <package>.sha1 is compared with the > actual files on the system and only the changed files are backuped. > This is done for all packages on the system and only one "configdb" is > created with changes from all packages. It's also dynamic so files no > longer available on the system (the package is removed) will be removed > from it. This is really interesting. I have been working on something very similar on the alpine linux project (http://alpinelinux.org). I think the concept is basicly the same so I'd like to share how we were thinking. First, splitting configs from binaries are essensial for upgrading. Second, you are normally not interested in configs per package but more configs per host, which leads to 1 config backup per host. It Looks like thats what you found out too. Second, we found out that all that actually got saved on the floppy, was all found in /etc direcotory. I think there was one pacakge (ppp) that needed to backup something in from /var but it was really config files that belongs in /etc. So the conlusion was, you only need to backup things in /etc. If you need to save things in /var, then you actually need a harddrive and are using the wrong tool for th task. This leads us to: create checksums (or save "status") of everything in /etc during package installation (during boot in other words). This is the "default", or "pristine" database. Do your changes in /etc. Then compare current /etc with the recorded status. Now you know what you need to backup (and thus don't really need the .local files) Nathan wrote a simple file integration checker (http://sfic.sourceforge.net) that could recursively prase a directory, and then saves the filesizes, create/mod times, permissions, checksums etc in a tdb database (http://sourceforge.net/projects/tdb) I wrote a wrapper script, a local backup manager that do the check and creates a tar archive on floppy. The local backup utility (lbu) is inspired by svn and works pretty much similar. lbu status - will list all changes shince last commit to floppy. "lbu status -a" will show all the changes. lbu commit floppy - will save all the modified files to a tar archine on floppy(you can also do a "lbu commit usb" to save to usb stick instead of floppy) lbu add - will add a file manually to the backup list (if you need to backup something thats outside /etc) Funny think is I got it working at the end of last week actually. > > Some of the advantages: > -Upgrading should be easier in most cases (config is preserved) I'm (currently) using apk-tools for the alpine project. It supports package upgrades. apk_add -u <package>. It will look for config files, backup, and then install the new config file as .apk-new and preserve the original one. It also updates the default/pristine database so next time you do a "lbu commit" it won't backup files that are identical to the new, updated config files. Then it should be possible to parse the /etc dir and look for .apk-new files, run a diff and merge in changes. (like gentoo's etc-update or freebsd's mergemaster) > -It is possible to create specific "configd" and "moddb" packages for > specific hardware or functionality without creating special packages > (WRAP, ...) > -The packages are "static", so no more corruption or "growing" root.lrp > -<package>.list and <package>.exclude.list can be removed We even removed <package>.local, since every config files should live in /etc. > Because this system creates some package incompatibility (no more .list > files) we plan to do this with an uClibc upgrade (which isn't backwards > compatible also). The changes are not very drastic and relative easy > implemented in buildtool, so we could make the change without a lot of > effort. > > Comments? If you are interested in testing the very same concept, but without any .local files and using Nathan's sfic utility, you can download the latest beta of alpine. http://tanael.org/alpine/v1.1/iso/alpine-1.1.3_beta3-060610-i386.iso http://tanael.org/alpine/v1.1/iso/alpine-1.1.3_beta3-060610-i386.iso.sha1 (warning! it's 137 MB on a 2Mbit shdsl line) You can also try run it from USB: http://tanael.org/alpine/v1.1/usbdrive/ Since the documetation is not so good, here are the basics to get started: To list available packages: apk_fetch -lv To install a package: apk_add <package> To configure the basics (incl networking): setup-alpine Try add/delete/modify anything in /etc, then run: lbu -h lbu status lbu commit -h lbu commit -n floppy -- Natanael Copa _______________________________________________ leaf-devel mailing list leaf-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/leaf-devel
