Looking Ahead - Upgrade

[Sam Varshavchik]

Rick Stevens writes:

> Gene Poole wrote:
>> In the near future I would like to upgrade my server machine from Fedora 8
>> x86_64 to Fedora 9 x86_64. This machine has several key components running,
>> including Oracle 10G, Samba, and Apache - Tomcat.
>> 
>> Has anyone any idea what I can expect so I can plan ahead?
> 
> Always back stuff up.  Expect it all to go to hell and force a
> reinstall.  That's the only truly safe way.

Well, one of my machines originally had Red Hat 3.3 installed, and it's been 
upgraded with every release since then, until the current Fedora 8 (not to 
mention all of its hardware replaced in the interim). It's as stable as a 
freshly-installed box.

Upgrades are never a problem, if you follow some simple, straightforward 
rules. The only problems you'll ever have will not be as a direct result of 
the upgrade, per se, but rather the new stuff occasionally not plainly 
working. I recall one upgrade, I think it was Red Hat 5, that loaded a 
kernel that had a bug that caused a complete freeze, and that was triggered 
only on certain hardware, and I won the lottery. That caused a little bit of 
excitement. Of course, a fresh install won't make much of a difference here.

The rules are pretty simple:

* Do not install stuff manually, cowboy-style. Always use rpm to install 
software packages, instead of crossing your fingers before running 'make 
install'.

* After each upgrade, open /root/upgrade.log, and filter out all the whining 
from rpm about the configuration files. For each configuration file, open 
the carried-over one that was left in place, take all the changes you have 
in the old file, manually merge it into the .rpmnew file, then 
replace the old configuration file with the .rpmnew file.

* Know your software. If you're running MySQL or Postgres, dump your 
database before the upgrade. Major dot-releases of Postgres will often 
refuse to boot up with the previous release's database. You'll need to nuke 
your entire DB, start Postgres and have it initialize a fresh DB, then load 
your dump. Other major software packages may have their own idiosyncrasies.

* Occasionally, every other release or so, use some rpm-foo to review the 
list of packages that were installed more than 2-3 years ago, and uninstall 
them. That's baggage that has been obsoleted, and nobody uses any more.


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