How can I upgrade my Slicehost VPS Ubuntu 7.10 slice to 8.10?
I have an Ubuntu 7.10 slice on Slicehost running my main web server. I want to update to Ubuntu 8.10 because the repositories are gone for 7.10 and I want the latest security and application upgrades.
Slicehost does not seem to let me dist-upgrade from 7.10 to 8.10, they suggested I buy a new VPS slice, upgrade it to what I need, port my data over, and then reimage my original slice from the 2nd slice. Has anyone else done this? Any better way to do it or pitfalls to watch out for while doing this? How long will my site be down if I use this method? Can I finish it in 2 hours on a Saturday?
There is no reason you should be down at all.
Set your DNS TTL low (30 min or lower if you can), and do it ahead of time.
Get the second slice. Install/port your software to it, and have it staged and ready to go.
Change your DNS. Within the TTL period, users that already had your old IP will still go to the old slice. New users will go to the new slice. After the TTL, everyone is using the new slice.
Reset your DNS TTL to whatever you had.
Retire the original slice. (I don't know why you would want to go back to it, the new slice already has what you want.)
If you have some state or something that has to stay in sync (e.g., user settings), then you might have to take the original slice before updating DNS. Users with the old IP will be down for the TTL period.
You pay for two slices the month you do this. I'm not sure what seems unreasonable about this, or why people think Slicehost might be giving you the run-around.
EDIT: The alternative to paying for two slices would be to upgrade in place: Take down your server, reimage the slice, reinstall your software. You'ld be down for the duration, which would likely be more than 2 hours.
It does seem like your host is giving you the run-around. Most likely, you'll have to have the two VPS's going for about 2 days. The first day to port your application (barring no serious issues), and the second, to give time for dns records to be updated to the new VPS.
If you do go this route, I'd try setting up a local 8.10 server and do a test run of moving your ap (if you haven't already done this). This will give you the closest estimate for how long your move will take.
I'm have a VPS on slicehost myself, and they've never upgraded the dist for me. I'm not totally sure why they suggested a new slice to do the upgrades. What I've done with my slice since Ubuntu 6 something, is just update the sources list, and upgrade up one step at a time.
Like jldugger mentioned, you have to upgrade to 8.04 before going to 8.10.