11–20 of 156 posts
> The main issue we've had with QEMU is that it has too many options you need to configure. For instance, enabling your VM to return unused RAM to the host requires at least three challenging tasks This just works on Hyper-V Linux guests btw. For all the crap MS gets they do some things very right.
No mention of Cloud Hypervisor [1]…perhaps they don’t know about it? It’s based in part on Firecracker and supports free page reporting, virtio-blk-pci, PCI passthrough, and (I believe) discard in virtio-blk. [1]: https://www.cloudhypervisor.org/
I really want VM's to integrate 'smarter' with the host. For example, if I'm running 5 VM's, there is a good chance that many of the pages are identical. Not only do I want those pages to be deduplicated, but I want them to be zero-copy (ie. not deduplicated after-the-fact by some daemon). To do that, the guest block cache needs to be integrated with the host block-cache, so that whenever some guest application tries…
Okay.
No mention of Cloud Hypervisor [1]…perhaps they don’t know about it? It’s based in part on Firecracker and supports free page reporting, virtio-blk-pci, PCI passthrough, and (I believe) discard in virtio-blk. [1]: https://www.cloudhypervisor.org/
We do, and we'd love to use it in the future. We've found that it's not ready for prime time yet and it's missing some features. The biggest problem was that it does not support discard operations yet. Here's a short writeup we did about VMMs that we considered: https://github.com/hocus-dev/hocus/blob/main/rfd/0002-worksp...
I really want VM's to integrate 'smarter' with the host. For example, if I'm running 5 VM's, there is a good chance that many of the pages are identical. Not only do I want those pages to be deduplicated, but I want them to be zero-copy (ie. not deduplicated after-the-fact by some daemon). To do that, the guest block cache needs to be integrated with the host block-cache, so that whenever some guest application tries…
An OS isn't large. Your spotify/slack/browser instance is of comparable size. Says more about browser based apps but still.
I really want VM's to integrate 'smarter' with the host. For example, if I'm running 5 VM's, there is a good chance that many of the pages are identical. Not only do I want those pages to be deduplicated, but I want them to be zero-copy (ie. not deduplicated after-the-fact by some daemon). To do that, the guest block cache needs to be integrated with the host block-cache, so that whenever some guest application tries…
Listen people, Firecracker is NOT A HYPERVISOR. A hypervisor runs right on the hardware. KVM is a hypervisor. Firecracker is a process that controls KVM. If you want to call firecracker (and QEMU, when used in conjunction with KVM) a VMM ("virtual machine monitor") I won't complain. But please please please, we need a word for what KVM and Xen are, and "hypervisor" is the best fit. Stop using that word for a user-lev…
Although I’ll note that the line between a VMM and hypervisor are not always clear. E.g., KVM includes some things that other hypervisors delegate to the VMM (such as instruction completion). And macOS’s hypervisor.framework is almost a pass through to the CPU’s raw capabilities.
Fly uses Firecracker, and they host long-running processes. I wonder what's their opinion about it.
I think their usecase makes a lot of sense as their workloads consume a predefined amount of ram. As a customer you rent a VM with a specified amount of memory so fly.io does not care about reclaiming it from a running VM.
This is why paying for dedicated memory is often more expensive than its counter part, because that dedicated memory is not considered as part of pooling.
Listen people, Firecracker is NOT A HYPERVISOR. A hypervisor runs right on the hardware. KVM is a hypervisor. Firecracker is a process that controls KVM. If you want to call firecracker (and QEMU, when used in conjunction with KVM) a VMM ("virtual machine monitor") I won't complain. But please please please, we need a word for what KVM and Xen are, and "hypervisor" is the best fit. Stop using that word for a user-lev…
Is it good to think of libvirt as a virtual machine mointor, or is that more "virtual machine management"?