I only have one linode running my live site. I'd love to rebuild my linode with ubuntu 11.04.
In order to minimize downtime, what's your strategy gracefully informing users of site maintenance? Do you redirect the site to some temporary maintenance page somewhere?

Why?

Not to stifle your joy here, but if it's working, and you don't need a specific feature of the new version, why upgrade?

Assuming you have a good reason to upgrade to a non-lts release, best thing to do is buy a 2nd node, create it how you want, shutdown both nodes, then swap the ips. (note both must be in the same data centre)

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+1 for second linode followed by IP swap. If you do it properly, you will have less than 1 minute of downtime. Then you won't need to worry about putting up "Under maintenance" signs or any such inconvenience.

I used the IP swap trick for a 512->768 upgrade, and it worked well. One thing to keep an eye out for is that swapping the IPs will shutdown the linodes for you, but it won't automatically queue a boot job. I spent several minutes waiting for the new linode to come back up only to realize it was waiting for me to tell it to start. Fortunately, this was a trial run on a site that wasn't live yet, so no harm done.

Other things:
- Make sure the new linode's configured with DHCP so it'll pick up the changed address when it boots after you do the switch. Or you could statically configure it with the proper address, though you'll need to be careful not to shoot yourself in the foot.
- Adding a private IP to a linode requires a shutdown/reboot. If you've got a lot of data to transfer between the old and new linodes, you'll want a private IP so it doesn't eat up your bandwidth.
- Keeping track of what changes you make to the default OS setup makes the process run a lot smoother in the future. I've got a text file full of commands that I can copy-and-paste to reproduce the setup of my linode. It's not worth making a proper stack script since rebuilding it is a very rare occurrence, but it's helpful to have a reference of what I've done.

For a 512->768 upgrade, though, a simple resize can be done in-place. It leads to a little bit of extra downtime, but it's a lot simpler.

Thanks for all your advice guys.

Stupid question, how do you configure the linode with DHCP?

Never mind. Figured out DHCP is enabled by default. Thanks guys.