Upgrading FreeBSD 9.2 to 10.0-RC4 on Rackpsace’s instance

In reality it turned out to be a fairly straightforward procedure:

• This is crucial. You must save XENHVM config before the upgrade otherwise you won’t be able to re-build the kernel which is required to bring the network up.

# cp /usr/src/sys/amd64/conf/XENHVM /root/amd64_XENHVM
# cp /usr/src/sys/i386/conf/XENHVM /root/i386_XENHVM

• Perform the upgrade as usual and just follow the instructions, i.e. reboot when you’re asked to:

# freebsd-update -r 10.0-RC4 upgrade
Looking up update.FreeBSD.org mirrors... 5 mirrors found.
Fetching metadata signature for 9.2-RELEASE from update5.freebsd.org... done.
Fetching metadata index... done.
Fetching 1 metadata patches. done.
Applying metadata patches... done.
Fetching 1 metadata files... done.
Inspecting system... done.

WARNING: This system is running a "xenhvm" kernel, which is not a
kernel configuration distributed as part of FreeBSD 9.2-RELEASE.
This kernel will not be updated: you MUST update the kernel manually
before running "/usr/sbin/freebsd-update install".

... Skipped for brevity ... 

To install the downloaded upgrades, run "/usr/sbin/freebsd-update install".

• Run “freebsd-update install”. When it’s done you’ll be asked to reboot the server. Do not think twice and reboot safely here.
• When the server comes up run “freebsd-update install” for the second time.
• In the end you’ll be asked to repeat “freebsd-update install” for the third time. Run it lightheartedly but do not reboot! Instead, you should rebuild the kernel here:

# cd /usr/src
# cp /root/amd64_XENHVM /usr/src/sys/amd64/conf/XENHVM
# cp /root/i386_XENHVM /usr/src/sys/i386/conf/XENHVM
# make buildkernel KERNCONF=XENHVM
# make installkernel KERNCONF=XENHVM
# shutdown -r now

• After reboot comes a moment of the glory:

# freebsd-version 
10.0-RC4