I'm excited about this project for several reasons. It's a totally open stack (Linux, Ganeti, Django, etc.), funded through a grant from Facebook based on code from Google and OSU OSL (including Google Code-In students). This is a great example of the open source community working together for the greater good.
Not to mention the fact that SPARCs, even under a common OS, are great for finding bugs that just don't happen on i386. Notably, the C standard only allows casting properly-aligned memory (e.g. typically, a chunk of memory with an address that is a multiple of four can be interpreted as a 32-bit integer, but this may not work for "unaligned" memory) - SPARCs will terminate your process with SIGBUS if you try this, whereas i386/amd64 machines will (slowly) perform the requested operation.
There are more differences, many related to multiple CPUs (SPARCs are not "cache-coherent".)
You can actually request that x86 machines trap on unaligned accesses too, by setting the AC flag in EFLAGS (pushf; orl $(1<<18), (%esp); popf). Unfortunately, it's common for the C standard library implementation to rely on aligned accesses on x86, so this isn't really feasible.
There's definitely a desire to build out more environments. Just decided to get it up and running on x86 first with both 32 and 64 bit architectures on a variety of Linux distributions.
How does this compare for most open source groups to the option of using Hudson on their own servers? Also, I looked at their list of planned hosts--I didn't see windows. A number of the open source projects that I release are cross platform. Does anyone have any insight if they plan to add instances of windows (xp, vista, 7) for testing? I guess I'll have to wait and see when it's open for general testers.
It differs in that this isn't just Hudson or some other testing software. We're providing a self service cloud that open source projects can use in lieu of Amazon, Linode or other paid providers.
Eventually windows support will be added. KVM/Xen supports it, so Ganeti does also. Where we're lacking is code to deploy a windows image on demand using Ganeti. We've started talking about how to implement it, but linux and unix based environments remain our primary target.
Its basically a virtualization cluster management system. Install it with KVM or Xen on a few servers, give it a lvm volume group to work with on each. You can then deploy and manage (migrate, fail over, grow, etc) virtual machines to the cluster in various configurations, including with mirrored disks using DRBD, all from the master node. It also has an HTTP API.
Ganeti. It sits a layer above KVM or Xen. The main difference from KVM proper is that it allows management of multiple KVM servers and storage nodes as a single cluster. You get failover, easy migration between nodes, balancing, etc.
With Ganeti Web Manager we're building towards software that will let you manage your own private or public cloud service.