AWS Adds support for nested virtualization(github.com)
70 pointsby sitole2 hours ago12 comments
  • boulosa minute ago
    I feel vindicated :). We put in a lot of effort with great customers to get nested virtualization running well on GCE years ago, and I'm glad to hear AWS is coming around.

    You can tell people to just do something else, there's probably a separate natural solution, etc. but sometimes you're willing to sacrifice some peak performance just have that uniformity of operations and control.

  • anuragan hour ago
    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.

    • iJohnDoean hour ago
      Was hoping this comment would be here. Firecracker and microVMs is a 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.

    • parhamnan hour ago
      whats the ~ perf hit of something like this?
      • largbaean hour ago
        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.
      • otterley41 minutes ago
        As a practical matter, anywhere from 5-15%.
  • sitole2 hours ago
    Support for nested virtualization has been added to the main SDKs. In the us-west-2 region, you can already see the "Nested Virtualization" option and use it with the new M8id, C8id, and R8id instance types.

    This is really big news for micro-VM sandbox solutions like E2B, which I work on.

  • gerdesjan hour ago
    Could 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.

    • paulfurtadoan hour ago
      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.

    • 38 minutes ago
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    • UltraSanean hour ago
      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.
  • blibble2 hours ago
    welcome AWS to 2018!
    • ssl-3an hour ago
      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.
      • otterley43 minutes ago
        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. That option was never disabled 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 meets customer standards

        4. Building a rock-solid control plane around it all

        It's not a trivial matter of flipping a bit.

        • raw_anon_1111a minute ago
          Seriously curious, don’t Firecracker VMs already run on EC2 instances under the hood when they host Lambda and Fargate?
        • QuinnyPig9 minutes ago
          I always enjoy the color you add to these conversations. Thanks!
        • sitole6 minutes ago
          Nitro is very interesting stuff
  • dk899637 minutes ago
    Would these thing be good for openclaw, agents?
    • CuriouslyC18 minutes ago
      Yeah, though honestly if I'm deploying anything I'd just build an image with nix rather than use nested virtualization.
  • ATechGuyan hour ago
    Would love to see performance numbers with nested virtualization, particularly that of IO-bound workloads.
  • apian hour ago
    What's the performance impact for nested virtualization in general? I'd think this would be adding multiple layers of MMU overhead.
    • blibble13 minutes ago
      depends on the workload and how they've done it

      pure CPU should be essentially unaffected, if they're not emulating the MMU/page tables in software

      the difference in IO ranges from barely measurable to absolutely horrible, depending on their implementation

      traps/vmexits have another layer to pass through (and back)

    • dwatttttan hour ago
      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.

    • otterley21 minutes ago
      As a practical matter, anywhere from 5-15%.
  • 2 hours ago
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  • farklenotabotan hour ago
    Sounds expensive for legacy apps
  • dangoodmanUTan hour ago
    hell yes, finally
  • bagelsan hour ago
    "* *Feature*: Launching nested virtualization. This feature allows you to run nested VMs inside virtual (non-bare metal) EC2 instances."