second, not so much... lost ssh.

I updated from 8.10 to 9.04 and all worked well. I was able to ssh in and the web server was running fine. So then i did step two and upgraded to 9.10, but am locked out of ssh now and the Linode Ajax console is not running well at all for me... Does anyone have any suggestions as to what I should look to first to try to resolve?
During the install, I kept all modified config files rather than accept the new ones. So, my.cnf, apache2 sites-available, etc.

Ok, Linode support helped me out on an easy fix for this...
"Ubuntu 9.10 requires the "Latest 2.6 Paravirt" kernel. Please change your configuration profile to adhere to this condition. Once you have made this change please reboot your Linode"

However, now mysql is having problems:
"The mysqli error was: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'"

If the ajaxterm isn't working well for you, you should try logging in via lish.

Agreed lish is a million times better than ajax, for your mysql problem check /var/log/yourhostname.err or wherever your my.cnf says errors are stored. See what it says in there.

and it appears i need to run MySQL_upgrade. Problem is, when i do I get an error:
Looking for 'mysql' as: mysql
Looking for 'mysqlcheck' as: mysqlcheck
Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/run/mysqld/mysqld.sock'
mysqlcheck: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) when trying to connect
FATAL ERROR: Upgrade failed

the pertinent part of syslog for MySQL is:
Apr 10 15:44:19 webserver mysqld_safe: Starting mysqld daemon with databases from /var/lib/mysql
Apr 10 15:44:19 webserver mysqld: 100410 15:44:19 [Note] Plugin 'FEDERATED' is disabled.
Apr 10 15:44:19 webserver mysqld: /usr/sbin/mysqld: Table 'mysql.plugin' doesn't exist
Apr 10 15:44:19 webserver mysqld: 100410 15:44:19 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
Apr 10 15:44:20 webserver mysqld: 100410 15:44:20 InnoDB: Started; log sequence number 0 43685
Apr 10 15:44:20 webserver mysqld: 100410 15:44:20 [ERROR] /usr/sbin/mysqld: unknown option '--skip-bdb'
Apr 10 15:44:20 webserver mysqld: 100410 15:44:20 [ERROR] Aborting
Apr 10 15:44:20 webserver mysqld:
Apr 10 15:44:20 webserver mysqld: 100410 15:44:20 InnoDB: Starting shutdown...
Apr 10 15:44:21 webserver mysqld: 100410 15:44:21 InnoDB: Shutdown completed; log sequence number 0 43685
Apr 10 15:44:21 webserver mysqld: 100410 15:44:21 [Warning] Forcing shutdown of 1 plugins
Apr 10 15:44:21 webserver mysqld: 100410 15:44:21 [Note] /usr/sbin/mysqld: Shutdown complete
Apr 10 15:44:21 webserver mysqld:
Apr 10 15:44:21 webserver mysqld_safe: mysqld from pid file /var/run/mysqld/mysqld.pid ended
Apr 10 15:44:33 webserver /etc/init.d/mysql[3619]: 0 processes alive and '/usr/bin/mysqladmin --defaults-file=/etc/mysql/debian.cnf ping' resulted in
Apr 10 15:44:33 webserver /etc/init.d/mysql[3619]: #007/usr/bin/mysqladmin: connect to server at 'localhost' failed
Apr 10 15:44:33 webserver /etc/init.d/mysql[3619]: error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'
Apr 10 15:44:33 webserver /etc/init.d/mysql[3619]: Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!
Apr 10 15:44:33 webserver /etc/init.d/mysql[3619]:

Thanks for the input folks.
The MySQL problem was resoved by commenting out skip-bdb from my.cnf
I found the answer here http://ubuntuforums.org/showthread.php? ... ost9104694

As a note for the future, you can upgrade directly between LTS releases. So if you are running 8.04 and your eventual goal is to run 10.04, then there is no need to upgrade 8.04 -> 8.10 -> 9.04 -> 9.10 -> 10.04, you can just go directly from 8.04 -> 10.04.

That said, 10.04 is not out yet, but the point still stands; no need for the in-between steps.