kata-containers VS ignite

> I actually wonder how much "overhead" a VM actually has. i.e. a linux kernel that doesn't do anything (say perhaps just boots to an init that mounts proc and every n seconds read in/prints out /proc/meminfo) how much memory would the kernel actually be using?

There's already some memory sharing available using DAX in Kata Containers at least: https://github.com/kata-containers/kata-containers/blob/main...

Seems like Fly.io Machines are trying reimplement Kata Containers with the Firecracker backend [0].

Kata has a guest image and guest agent to run multiple isolated containers [1].

[0] https://katacontainers.io/

[1] https://github.com/kata-containers/kata-containers/blob/main...

> Last time I looked (a few months ago), the documentation was pretty sparse or outdated.

It still is, though it works somewhat seamlessly when installing with https://github.com/kata-containers/kata-containers/blob/main...

Though only one of the hypervisors works well.

Better to use a secure VM, can even get container-like VMs with kata-containers

As I understand,Kata Containers

Kubernetes using Kata containers as a containerd backend

https://github.com/kata-containers/kata-containers/blob/main...

My home k8s cluster is now "locked down" using micro-vms (kata-containers[0]), pod level firewalling (cilium[1]), permission-limited container users, and mostly immutable environments. Given how quickly I rolled this out; the tools to enhance cluster environment security seem more accessible now than my previous research a few years ago.

I know it's not exactly a production setup, but I really do feel that it's the most secure runtime environment I've ever had accessible at home. Probably more so than my desktops, which you could argue undermines most of my effort, but I like to think I'm pretty careful.

In the beginning I was very skeptical, but being able to just build a docker/OCI image and then manage its relationships with other services with "one pane of glass" that I can commit to git is so much simpler to me than my previous workflows. My previous setup involved messing with a bunch of tools like packer, cloud-init, terraform, ansible, libvirt, whatever firewall frontend was on the OS, and occasionally sshing in for anything not covered.

[0] https://github.com/kata-containers/kata-containers

Not a drop-in replacement: the OCI image entry point is not automatically executed. https://github.com/weaveworks/ignite/issues/874 (issue opened in 2021).

Resource usage. Running a full VM to execute only two processes is a big waste of the limited resources of my server (8GB RAM, Celeron processor). I searched and I found something to limit the resource usage and minimize the attack surface of the guest OS: Weave Ignite/Firecracker/MicroVMs.

> If it's not hard to name a thing that Firecracker makes difficult for a serverside workload, could you... name one?

I already did that with live migration. But ok.

Encrypted storage: https://github.com/firecracker-microvm/firecracker/issues/65...: WONTFIX

The answer given is appropriate for firecracker use cases but insufficient otherwise. I'm not anti-firecracker; it's the right choice for many things. Just not all things.

The sort of VM I want orchestrated has encrypted (by contract) multi-pathed network block devices to encrypted storage volumes. 3-10 per tenant. This is trivial for a full-featured kernel; multi-path just works, encryption just works.

VLAN: https://github.com/weaveworks/ignite/issues/810: Open. Maybe one day.

Again, trivial for a full-featured Linux kernel.

I think you're missing the point. It's not about what hypothetical thing firecracker can or can't do. It's about elevating VM orchestration to some degree of parity with what has been created for container orchestration. These VMs and their complex storage and networking requirements should be modeled as we model containers now; through an orchestration system that makes management easy and as foolproof as possible. The fact that firecracker isn't sufficient to be the Micro-VM of choice for this isn't relevant.