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Why is docker for Mac a thing and docker for FreeBSD would not be possible? My understanding is that it's just VMs. Don't they have VMs in FreeBSD?

by forty 5y ago

sofixa 5y ago
> Why is docker for Mac a thing and docker for FreeBSD would not be possible? My understanding is that it's just VMs. Don't they have VMs in FreeBSD It's not. Docker uses Linux kernel features such as namespaces and cgroups, and doesn't virtualisation. The only way to run Docker on macOS or FreeBSD is through a Linux-based VM for those Linux kernel features.
- Arnavion 5y ago
  Docker is not married to Linux kernel features. Docker on Windows uses a Linux VM to run Linux containers but also has a Hyper-V backend to run Windows containers. Microsoft even ships a first-party-supported version of Docker called Moby for on-prem container engine installs (eg as part of Azure IoT Edge that runs Docker containers on IoT devices) that only runs Windows containers (with the Hyper-V backend).
  - sofixa 5y ago
    As you said yourself, Windows containers is a whole different thing that only runs on Windows, and is only for Windows ( you can't run a Windows container on Linux for instance). Hence it's more like *BSD Zones that just calls itself the same as Linux containers, and CLI compatible with Docker, and not in any meaningful way related to actual Docker and Linux containers. PS: why would anyone use Windows for IoT stuff? Seems like a complete waste of resources. And in general, Windows containers are very rare in the wild
    - pjmlp 5y ago
      Windows containers are quite common on Microsoft shops, used to deploy .NET and C++ workloads based on IIS, Sitecore, SharePoint, SQL Server,... Additionally many new security features make use of containers as part of their design, e.g. Driver Guard or SafeKernel.
    - quickthrower2 5y ago
      I found porting an app to a Windows container pretty hard because of IIS issues. Unless you have a straightforward app it is not nice. We will wait until we are on .Net 5 + and then run it in a Linux container.
- forty 5y ago
  Yes my point was that docker on Mac is just VMs and they could simply do the same on freeBSD
kristianp 5y ago
FreeBSD has jails, which are equivalent to containers. Using docker in a vm isn't the best solution due to performance of things like file system access.

Why is docker for Mac a thing and docker for FreeBSD would not be possible? My understanding is that it's just VMs. Don't they have VMs in FreeBSD?

by forty 5y ago

Why is docker for Mac a thing and docker for FreeBSD would not be possible? My understanding is that it's just VMs. Don't they have VMs in FreeBSD?

sofixa 5y ago

> Why is docker for Mac a thing and docker for FreeBSD would not be possible? My understanding is that it's just VMs. Don't they have VMs in FreeBSD It's not. Docker uses Linux kernel features such as namespaces and cgroups, and doesn't virtualisation. The only way to run Docker on macOS or FreeBSD is through a Linux-based VM for those Linux kernel features.

Arnavion 5y ago
Docker is not married to Linux kernel features. Docker on Windows uses a Linux VM to run Linux containers but also has a Hyper-V backend to run Windows containers. Microsoft even ships a first-party-supported version of Docker called Moby for on-prem container engine installs (eg as part of Azure IoT Edge that runs Docker containers on IoT devices) that only runs Windows containers (with the Hyper-V backend).
- sofixa 5y ago
  As you said yourself, Windows containers is a whole different thing that only runs on Windows, and is only for Windows ( you can't run a Windows container on Linux for instance). Hence it's more like *BSD Zones that just calls itself the same as Linux containers, and CLI compatible with Docker, and not in any meaningful way related to actual Docker and Linux containers. PS: why would anyone use Windows for IoT stuff? Seems like a complete waste of resources. And in general, Windows containers are very rare in the wild
  - pjmlp 5y ago
    Windows containers are quite common on Microsoft shops, used to deploy .NET and C++ workloads based on IIS, Sitecore, SharePoint, SQL Server,... Additionally many new security features make use of containers as part of their design, e.g. Driver Guard or SafeKernel.
  - quickthrower2 5y ago
    I found porting an app to a Windows container pretty hard because of IIS issues. Unless you have a straightforward app it is not nice. We will wait until we are on .Net 5 + and then run it in a Linux container.
forty 5y ago
Yes my point was that docker on Mac is just VMs and they could simply do the same on freeBSD

kristianp 5y ago

FreeBSD has jails, which are equivalent to containers. Using docker in a vm isn't the best solution due to performance of things like file system access.