Article title is a bit click-baity. The article is only talking about Docker Desktop on Mac or Windows. Docker Linux have not been using microVMs for a decade.
So what is currently the best way to run docker images in microvm these days? The article is pushing for docker sandboxes, but the "you need a docker login" makes is pretty much no-go for my use case.
I was just exploring the new docker sandbox and saw that they could retain all your data in/out of the sandbox for 30 days. I wash my hand of docker, use with care. Data is gold and lots of companies are now going to be giving their "free" products as a sort of trojan horse to steal your data.
Docker *Desktop*, not Docker Engine. Most uses of Docker, at least until Kubernetes shifted to containerd, were the latter. The reality is that most running production containers today share a kernel.
Dynamic memory hot-plugging is still not as efficient. So if you don't want strict isolation between containers or individual sandboxes around each one of them, avoid VMs to achieve the highest density per box.
> What if I told you that Docker Desktop has always used microVMs?
I'd say that I don't think it's that relevant? Hopefully everyone was aware that you required a VM to run Linux software on Windows and Mac, and then who would really care about what VM docker used to run development containers? The more expendable the better. Hopefully nobody is using a Windows PC with docker desktop in a production scenario - but given how utterly incompetent some people I met was, I'd not be too surprised from that
I wonder if this is due to Microsoft pushing forward with wslc in the past week or so.
I tried pure wslc for a project or two this past week. It got me 90% of the way but not all the way. Still pretty impressive, even if it is another example of extend and extinguish.
Yawn. IBM/AIX's WPARs & LPARs, Sun/Solaris' dynamic system domains & zones, BSD jails. How many times are we going to pat ourselves on the back for reinventing the wheel?
We know. But of course the hype of "microVMs" is just a rebranding of existing technologies with some modifications, macOS needed extra virtualization technologies just for containers for years:
Docker Desktop macOS (until 2025): QEMU + Virtualization.framework + Linux kernel (without extra drivers) = "microVM".
Now they use the native Apple virtualization libraries instead of QEMU for both containers and microVMs. [0] Linux never needed to use KVM for containers, but requires it for microVMs:
Linux: KVM + Linux kernel (without extra drivers) = Firecracker "microVM".
In reality, it is different depending on the OS that you are using.
Article title is a bit click-baity. The article is only talking about Docker Desktop on Mac or Windows. Docker Linux have not been using microVMs for a decade.
It's still not a bad idea to reduce attack surface. A VM is much easier to harden than a kernel.
In those two cases they also use VMs because they don't really have another cheap option.
Neither XNU/Darwin nor Windows have had an oob option for running Linux images. WSL is rather new in comparison.
Of course it’s not a bad idea. It’s just a bad article.
So what is currently the best way to run docker images in microvm these days? The article is pushing for docker sandboxes, but the "you need a docker login" makes is pretty much no-go for my use case.
Apple containers
> What if I told you that Docker Desktop has always used microVMs?
Then I would say your title is wildly misleading.
Its bending history to call what before were Linux Vms inside Mac or Windows to have containers to that is a real MicroVM.
And the current Sandboxes dont offer the same security model - See Docker Sandboxes 0.42.0 security update: CVE-2026-77179 and CVE-2026-79994
https://docs.docker.com/security/security-announcements/
I was just exploring the new docker sandbox and saw that they could retain all your data in/out of the sandbox for 30 days. I wash my hand of docker, use with care. Data is gold and lots of companies are now going to be giving their "free" products as a sort of trojan horse to steal your data.
Docker *Desktop*, not Docker Engine. Most uses of Docker, at least until Kubernetes shifted to containerd, were the latter. The reality is that most running production containers today share a kernel.
Dynamic memory hot-plugging is still not as efficient. So if you don't want strict isolation between containers or individual sandboxes around each one of them, avoid VMs to achieve the highest density per box.
Is all of docker one “micro” VM though? Or does each container get a clean, fresh one?
It’s all one lightweight VM. Containers share the VM’s kernel.
The shared kernel/lack of isolation between the cotnainer workloads is the model that this article isn't really touching but is really important.
Because the current needs are extremely lightweight and isolated environments i.e. vm per workload rather than shared.
And there's been a lot of wonderful innovations happen there
So no micro VMs at all
> What if I told you that Docker Desktop has always used microVMs?
I'd say that I don't think it's that relevant? Hopefully everyone was aware that you required a VM to run Linux software on Windows and Mac, and then who would really care about what VM docker used to run development containers? The more expendable the better. Hopefully nobody is using a Windows PC with docker desktop in a production scenario - but given how utterly incompetent some people I met was, I'd not be too surprised from that
I wonder if this is due to Microsoft pushing forward with wslc in the past week or so.
I tried pure wslc for a project or two this past week. It got me 90% of the way but not all the way. Still pretty impressive, even if it is another example of extend and extinguish.
One reason I think a distinction is made is that native Docker-in-Docker can be a real pain, but Docker in a Firecracker microVM "just works".
I often wonder what would have happened if rkt had been more successful.
And yet it's never picked by coding agents for sandboxes -> https://armature.tech/leaderboards#app/sandboxes
Yawn. IBM/AIX's WPARs & LPARs, Sun/Solaris' dynamic system domains & zones, BSD jails. How many times are we going to pat ourselves on the back for reinventing the wheel?
Lots. Remember the first VM OS? Running on IBM mainframes? Do you remember what the name of it was? Or when that came out?
Do you remember VMS on DEC hardware? And again, which decade did that come out?
Yeah, this wheel is going to continue to be re-invented for as long as computers exist.
Damm...thats going waayy back - but I want to say VS/VME (VM/VME) in the early 70s and vms in the mid 70s ?
Most of those are shared kernel, though, which is very much what you want to avoid if security is a primary goal.
...*on macOS only and runs qemu as the emulator.
We know. But of course the hype of "microVMs" is just a rebranding of existing technologies with some modifications, macOS needed extra virtualization technologies just for containers for years:
Now they use the native Apple virtualization libraries instead of QEMU for both containers and microVMs. [0] Linux never needed to use KVM for containers, but requires it for microVMs:
In reality, it is different depending on the OS that you are using.
[0] https://www.docker.com/blog/docker-desktop-for-mac-qemu-virt...