Circle CI MacOS Build Image questions


Hi, I am new to Circle CI, and I have a general question about how MacOS Build Image on Circle CI works.

Q1: I have some docker experience, and I think if we want to build Xcode project, we can only do it in "docker on Mac " + “Native Xcode”, is that correct?

Q2: So Circle CI just run docker container on OSX Server in backend, and connect to native Xcode to do the build, is that correct?

Q3: If Circle CI doesn’t run docker container on OSX server but on Linux, it use something like “OSX Docker KVM” solution?

Thanks in advance.


Hi there,
I’m not 100% sure, but pretty confident, that Docker images are all based on Linux. So my guess would be some other kind of macOS VM.


@JanBrinker, thank you for respond, so it will be some kind of circle version of kvm to run macOS virtual machine in linux docker.