This is a big deal because you can now run Firecracker/other microVMs in an AWS VM instead of expensive AWS bare-metal instances.
GCP has had nested virtualization for a while.
AWS Adds support for nested virtualization
11–20 of 124 posts
Re: AWS Adds support for nested virtualization
#12welcome AWS to 2018!
Yep. It's pretty boring. I've been using it at home for years and years with libvirt on very not-special consumer hardware. I guess the AWS clown is finally catching up on this one little not-new-at-all thing.
Re: AWS Adds support for nested virtualization
#13This is a big deal because you can now run Firecracker/other microVMs in an AWS VM instead of expensive AWS bare-metal instances. GCP has had nested virtualization for a while.
whats the ~ perf hit of something like this?
Re: AWS Adds support for nested virtualization
#14What's the performance impact for nested virtualization in general? I'd think this would be adding multiple layers of MMU overhead.
From memory, the virtualisation operations themselves aren't nested. The VM instructions interact with the external virtualisation hardware, so it's more of a cooperative situation, e.g. a guest can create & manage virtualisation structures that are run alongside it.
I don't know if this applies to the specific nested virtualisation AWS are providing though.
Re: AWS Adds support for nested virtualization
#15hell yes, finally
Re: AWS Adds support for nested virtualization
#16Could someone explain why this is might be a big deal? I remember playing with nested virty some years ago and deciding it is a backwards step except for PoC and the like. Given I haven't personally run out of virty gear, I never needed to do a PoC.
It is great for isolation. There are so many VM based containerization solutions at this point, like Kata Containers, gvisor, and Firecracker. With kata, your kubernetes pods run in isolated VMs. It also opens the door for live migration of apps between ec2 instances, making some kinds of maintenance easier when you have persistent workloads. Even if not for security, there are so many ways a workload can break a machine such that you need to reboot or replace (like detaching an ebs volume with a mounted xfs filesystem at the wrong moment).
The place I've probably wanted it the most though is in CI/CD systems: it's always been annoying to build and test system images in EC2 in a generic way.
It also allows for running other third party appliances unmodified in EC2.
But also, almost every other execution environment offers this: GCP, VMWare, KVM, etc, so it's frustrating that EC2 has only offered it on their bare metal instance types. When ec2 was using xen 10+ years ago, it made sense, but they've been on kvm since the inception of nitro.
Re: AWS Adds support for nested virtualization
#17Could someone explain why this is might be a big deal? I remember playing with nested virty some years ago and deciding it is a backwards step except for PoC and the like. Given I haven't personally run out of virty gear, I never needed to do a PoC.
You can now run VMs inside a cheaper AWS instance instead of having to pay for an entire bare-metal instance. This is useful for things like network simulation where you use QEMU to emulate network hardware.
Re: AWS Adds support for nested virtualization
#18This is a big deal because you can now run Firecracker/other microVMs in an AWS VM instead of expensive AWS bare-metal instances. GCP has had nested virtualization for a while.
whats the ~ perf hit of something like this?
Nowadays nested just wastes the extra operating system overhead and I/O performance if your VM doesn't have paravirtualization drivers installed. CPUs all have hardware support.
Re: AWS Adds support for nested virtualization
#19This is a big deal because you can now run Firecracker/other microVMs in an AWS VM instead of expensive AWS bare-metal instances. GCP has had nested virtualization for a while.
Was hoping this comment would be here. Firecracker and microVMs are good use-case. Also, being able to simply test and develop is a nice to have.
Nested virtualization can mean a lot of things. Not just full VMs.
Re: AWS Adds support for nested virtualization
#20welcome AWS to 2018!
Yep. It's pretty boring. I've been using it at home for years and years with libvirt on very not-special consumer hardware. I guess the AWS clown is finally catching up on this one little not-new-at-all thing.
I was an Amazon EC2 Specialist SA in a prior role, so I know a little about this.
If EC2 were like your home server, you might be right. And an EC2 bare metal instance is the closest approximation to that. On bare metal, you've always been free to run your own VMs, and we had some customers who rolled their own nested VM implementations on it.
But EC2 is not like your home server. There are some nontrivial considerations and requirements to offer nested virtualization at cloud scale:
1. Ensuring virtualized networking (VPC) works with nested VMs as well as with the primary VM
2. Making sure the environment (VMM etc) is sufficiently hardened to meet AWS's incredibly stringent security standards so that nesting doesn't pose unintended threats or weaken EC2's isolation properties. EC2 doesn't use libvirt or an off-the-shelf KVM. See https://youtu.be/cD1mNQ9YbeA?si=hcaZaV2W_hcEIn9L&t=1095 and https://youtu.be/hqqKi3E-oG8?si=liAfollyupYicc_L&t=501
3. Ensuring performance and reliability meets customer standards
4. Building a rock-solid control plane around it all
It's not a trivial matter of flipping a bit.