Building Binary Packages in Gentoo
In gentoo it is possible to build binary packages from already installed packages to avoid recompiling them e.g. on another machine. Gentoo provides a package called quickpkg for this which can package single packages for binary distribution. It is also possible to package all installed packages with quickpkg "*/*". The binary packages are then located in /usr/portage/packages/.
However when using quickpkg to package the whole system I strongly recommend to use --include-config y as by default quickpkg does not include config files in the binary packages. This will lead to erasing all configuration files from the machine that is using the binary host. This will most likely brick your system.
To use these binary packages on another machine you can simply host them on a http server and enter the server URI into the PORTAGE_BINHOST variable in your make.conf.
PORTAGE_BINHOST="https://user:password@my.own.server/"
I used a small go program to serve my binary packages which I bundled in a small docker container. You can use it to host your own binary packages and secure them with a http basic auth.
$ docker run -p 3000:3000 -v /usr/portage/packages:/content fin1ger/serve --auth user:password
The source code for the go program is located on github.
When doing your next system upgrade you can just use --buildpkg on your emerge command and binary packages will be build automatically for all packages of this upgrade.
Or short:
$ emerge -NDauvb
After all, remember always keeping a backup of your previous system as things can go wrong any time (not that I have bricked my system when doing this)…