25 Jul 2022
No Docker on the Mac Pro 3,1
My daily-driver home computer is an older Mac Pro 3,1 (early 2008) running High Sierra (Mac OS 10.13), mostly because I’ve been too lazy to get a new video card for it that’s compatible with Mojave or later. This creates a slight problem, because Docker Desktop only supports the latest version of Mac OS and the two preceding ones.
According to this StackOverflow question, the latest Docker Desktop version that will run on High Sierra is 184.108.40.206, which can be obtained from Docker.com under Previous Versions. It should be a 421MB file called “Docker.dmg”.
For some reason, the DMG took a very long time to verify on my system. But then I just dragged it into the Applications folder (on Mac OS, Docker runs entirely in userspace).
Sadly, it ended up barfing at me because it didn’t like the processors (allegedly) in my Mac Pro 3.1… I think that’s a bit of a lie, but it appears the solution involves flashing the EFI.
Although that updater says I’m already running the latest EFI, which is curious, since that ought to allow Docker to work. Supposedly. I don’t quite get it.
A bit more research suggests that perhaps the processors in this machine don’t quite have the features Docker requires? From this forum post:
Extended Page Tables (EPT)
Unrestricted Guest (UG)
those features are available on all Core i-3/5/7 CPUs, but not on older models as Core2Duo.
So from Westmere (2010), Arrandale (2010), Sandy Bridge (2011) and later architecture.
Nehalem Xeons lack UG too, that’s why Docker don’t work with MP4,1 and original single CPU MP5,1 Xeons and people have to upgrade to Westmere Xeons for it to work.
Well, that’s a bit disappointing. Guess it’s off to Linux-on-the-bare-metal land.