Lights Out Upgrade to Fedora Core 17.

Upgrading to Fedora Core 17 on a headless unit proved difficult.

I was upgrading from FC16 - had a disk failure on the FC15 system I described in the earlier post and installed FC16 on the replacement drive.

Pre-upgrade supports VNC access to make this possible - but there were hiccups.

1. IIRC pre upgrade did not configure grub correctly and reboot just brought me back to FC16 - I had to go down to the system and choose the pre-upgrade kernel while booting (this is a known bug: here and here)
2. Once the install was started, the vnc server was started as requested during pre-upgrade. I connected to the vnc server and accidentally closed the vnc viewer and could not connect back to the vnc server! This is also known and thanks to Ambarish for the workaround:
1. I downloaded the debug symbols for the tiger vnc server in an FC17 system running in a virtual machine (as the virtual machine was a 64 bit system, I had to specify the architecture for my 32 bit system): setarch=i686 yumdownloader --enablerepo fedora-debuginfo tigervnc-debuginfo
2. Use rpm2cpio to convert to cpio archive and extract the contents
3. Copy the entire contents to the system being upgraded (e.g. at /tmp/d).
4. Fire up gdb and point it to the debug symbols: 
1. Load symbols:
   set debug-file-directory /tmp/d/usr/lib/debug
2. Set source search directory:
   directory /tmp/d/usr/src/.../tigervnc-1.0.1/
3. Attach to running Xvnc (vnc server)
4. break at rfb::VNCSConnectionST::checkIdleTimeout()
5. Try to connect with vnc viewer and when you hit the breakpoint
1. set rfb::Server::idleTimeout.value=600
2. set rfb::Server::neverShared.value = false
6. And, voila you are connected to the vnc server again!
3. But, now the upgrade is hung at upgrading the package sbcl! Again, a known bug. Kill the process from a VT console and the upgrade continues...

Interestingly, cleaning up after pre upgrade as per the instructions, I found FC14/FC15 packages - where did they come from?! I had a pristine FC16 install before the upgrade...