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Intertwined with this announcement of an new instance type, is that it uses a non-Xen hypervisor. Has anyone booted one yet? Is it KVM or something from scratc

Intertwined with this announcement of an new instance type, is that it uses a non-Xen hypervisor. Has anyone booted one yet? Is it KVM or something from scratch that AWS wrote?

joemag 9y ago
It's based on KVM: https://aws.amazon.com/ec2/faqs/#compute-optimized https://aws.amazon.com/ec2/faqs/#compute-optimized (sorry for crappy link, can't figure out how to link directly to the appropriate question. Search for "What is the underlying hypervisor on C5 instances" question).
captainkrtek 9y ago
https://aws.amazon.com/ec2/faqs/#compute-optimized https://aws.amazon.com/ec2/faqs/#compute-optimized " Q. What is the underlying hypervisor on C5 instances? C5 instances use a new EC2 hypervisor that is based on core KVM technology. "
nnx 9y ago
What’s the benefit of KVM over Xen these days?
- alpb 9y ago
  I am also curious. I found this article which might help a little bit: https://www.theregister.co.uk/2017/01/30/google_cloud_kicked_qemu_to_the_kerb_to_harden_kvm/ https://www.theregister.co.uk/2017/01/30/google_cloud_kicked...
- abdulla 9y ago
  KVM can take better advantage of hardware acceleration than Xen. Xen requires a modified guest, which traps back to the host more frequently.
  - wmf 9y ago
    Is that true with the newer modes? https://wiki.xen.org/wiki/Understanding_the_Virtualization_Spectrum https://wiki.xen.org/wiki/Understanding_the_Virtualization_S...
    - abdulla 9y ago
      This is based on a cursory examination of [1], so I may be off-base. But Xen appears to rely on the host for many things that can be, and often are, hardware accelerated in KVM. Searching for CONFIG_XEN_PVHVM, it doesn't appear to cover much. [1] https://github.com/torvalds/linux/blob/master/arch/x86/xen/ https://github.com/torvalds/linux/blob/master/arch/x86/xen/
- _msw_ 9y ago
  It's difficult to make an simple comparison because neither hypervisor is used "out of the box" by EC2. For example, a lot of hypervisor benchmark comparisons focus on I/O performance, but the latest generation EC2 instances offload networking and storage processing to hardware. This is the case for both for instances that use Xen and C5 that uses the new KVM-based hypervisor. Since both hypervisors have very good support for hardware virtualization technology, it becomes more of an architecture decision. Practically speaking, it is a little bit easier to build a very small footprint hypervisor with the core KVM code than Xen.
deleted 9y ago
[deleted]
QuinnyPig 9y ago
There must be something we can test Maybe find a new regression Should we try it on a db shard? Or exercise some discretion... instance sizes aren’t powers of two The discount's just 15 percent We can hand wave that away It shouldn’t cause a downtime event Let’s be adults here I say... Everything xen, everything xen I don't think so Everything xen, everything xen I don't think so — Bush, Everything Xen
talawahdotnet 9y ago
Very interesting. Has anyone noticed any difference in boot times? If they are announcing things like a brand new hypervisor ahead of re:Invent one wonders what they are saving for the main event...is it too much to hope for managed Kubernetes?
- talawahdotnet 9y ago
  Just did a quick test. It booted up in about 11s vs around 19s for Xen. I did notice that it took a while for the status check to go green though. There was a warning message saying that it couldn't connect to the instance. I was able to SSH just fine though.

Intertwined with this announcement of an new instance type, is that it uses a non-Xen hypervisor. Has anyone booted one yet? Is it KVM or something from scratch that AWS wrote?

joemag 9y ago

It's based on KVM: https://aws.amazon.com/ec2/faqs/#compute-optimized https://aws.amazon.com/ec2/faqs/#compute-optimized (sorry for crappy link, can't figure out how to link directly to the appropriate question. Search for "What is the underlying hypervisor on C5 instances" question).

captainkrtek 9y ago

https://aws.amazon.com/ec2/faqs/#compute-optimized https://aws.amazon.com/ec2/faqs/#compute-optimized " Q. What is the underlying hypervisor on C5 instances? C5 instances use a new EC2 hypervisor that is based on core KVM technology. "

nnx 9y ago

What’s the benefit of KVM over Xen these days?

alpb 9y ago
I am also curious. I found this article which might help a little bit: https://www.theregister.co.uk/2017/01/30/google_cloud_kicked_qemu_to_the_kerb_to_harden_kvm/ https://www.theregister.co.uk/2017/01/30/google_cloud_kicked...
abdulla 9y ago
KVM can take better advantage of hardware acceleration than Xen. Xen requires a modified guest, which traps back to the host more frequently.
- wmf 9y ago
  Is that true with the newer modes? https://wiki.xen.org/wiki/Understanding_the_Virtualization_Spectrum https://wiki.xen.org/wiki/Understanding_the_Virtualization_S...
  - abdulla 9y ago
    This is based on a cursory examination of [1], so I may be off-base. But Xen appears to rely on the host for many things that can be, and often are, hardware accelerated in KVM. Searching for CONFIG_XEN_PVHVM, it doesn't appear to cover much. [1] https://github.com/torvalds/linux/blob/master/arch/x86/xen/ https://github.com/torvalds/linux/blob/master/arch/x86/xen/
_msw_ 9y ago
It's difficult to make an simple comparison because neither hypervisor is used "out of the box" by EC2. For example, a lot of hypervisor benchmark comparisons focus on I/O performance, but the latest generation EC2 instances offload networking and storage processing to hardware. This is the case for both for instances that use Xen and C5 that uses the new KVM-based hypervisor. Since both hypervisors have very good support for hardware virtualization technology, it becomes more of an architecture decision. Practically speaking, it is a little bit easier to build a very small footprint hypervisor with the core KVM code than Xen.

deleted 9y ago

[deleted]

QuinnyPig 9y ago

There must be something we can test Maybe find a new regression Should we try it on a db shard? Or exercise some discretion... instance sizes aren’t powers of two The discount's just 15 percent We can hand wave that away It shouldn’t cause a downtime event Let’s be adults here I say... Everything xen, everything xen I don't think so Everything xen, everything xen I don't think so — Bush, Everything Xen

talawahdotnet 9y ago

Very interesting. Has anyone noticed any difference in boot times? If they are announcing things like a brand new hypervisor ahead of re:Invent one wonders what they are saving for the main event...is it too much to hope for managed Kubernetes?

talawahdotnet 9y ago
Just did a quick test. It booted up in about 11s vs around 19s for Xen. I did notice that it took a while for the status check to go green though. There was a warning message saying that it couldn't connect to the instance. I was able to SSH just fine though.