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diff --git a/README.chroot-building b/README.chroot-building new file mode 100644 index 0000000..0c55d1d --- /dev/null +++ b/README.chroot-building @@ -0,0 +1,93 @@ + -*- mode: indented-text -*- + + + Building in chroot environments with sbuild + ------------------------------------------- + + Roman Hodek, June 7th 2000 + + +Starting with revision 1.133, sbuild can build packages also in a +chroot environment. (You also need buildd-addpkg >= 1.5). There are +different such environments for each distribution. The advantages of +this are: + + - You can build for different distributions on the same machine + without headaches about shared library version or the like. + + - Badly programmed build procedures can't modify files on the build + host. + + - The access time check for binaries used without a source dependency + becomes a bit more reliable, because normal user activities can't + cause an atime change. + +It works like in the following outline: + + - For each distribution (stable, frozen, unstable), there's a + separate installation in (e.g.) /usr/local/chroot/DIST. (This path + isn't hardwired, but used in this documentation.) + + - The chroot environment can be prepared with buildd-setup-chroot. + + - If in the build directory a symlink chroot-DIST exists (and the + build is for DIST), then sbuild will unpack the sources in + chroot-DIST/build/USERNAME and build the package there. + dpkg-buildpackage will be called under chroot, so that the whole + build process can't access files outside the build root. + + - All apt and dpkg and similar operations are also chroot-ed, so only + the chroot environment for that distribution is affected. That way, + different shared lib versions can coexist on the same machine and + the like. (It also reduces waiting time for parallel builds: If + they're for different distributions, installations can happen at + the same time and don't need to wait for each other.) + +Ok, now a bit more slowly: + +Best you prepare your chroot environments with the script +buildd-make-chroot. It does lots of things automatically. However, +manual fixes may be required. buildd-make-chroot is usually called +as: + + sudo buildd-make-chroot buildd DIST chroot-DIST http://optional.nearby.mirror/debian + +This will call debootstrap 0.3.2 or higher to create a new chroot, and then set +it up for the buildd user specified. + +Ok, after the chroot environments for all the distributions you want +are set up, you can start building in them. sbuild recognizes the +chroot environments by the existance of a chroot-DIST symlink in its +build directory (the dir where sbuild is started). If such a link +doesn't exist for the requested distribution, a normal build in the +host filesystem is performed like you're used to. + +If, however, the symlink exists, it should point to the root of the +chroot environment. Sources are unpacked in +chroot-DIST/build/USERNAME. (The username is appended so that multiple +users can utilize the chroot environment at the same time without +mixing the source trees.) All checks for packages and package +installations are performed --of course-- in the chroot. After +building, the .debs and the .changes file are moved back to the normal +build directory. (If a build fails, the source tree isn't moved back +but remains in chroot-DIST/build/USERNAME.) + +One point still worth mentioning is how the AddPkg directories are +handled. Those directories contain freshly built packages that might +be needed for building other packages before they're installed in the +archive. Since revision 1.5 of buildd-addpkg, the AddPkg packages are +separated by distribution, which is necessary to export them +selectivly into the chroot environments. For example, in the frozen +chroot, only AddPkg/stable and AddPkg/frozen will be mounted but not +AddPkg/unstable, because unstable packages may not be used for +building frozen packages. Likewise the stable chroot mounts only +AddPkg/stable, and the unstable one mounts all three. + +The access from inside the chroot environments to the AddPkg packages +works over the local NFS mounts described above. The appropriate deb +lines in sources.list should have been created by buildd-setup-chroot. + +The installation into an AddPkg directory by sbuild and buildd-addpkg +is done from outside the chroot environment. + + |