Split mode upgrade - aka A/B partitions

[tomcounihan]

Hello Azure Linux team,
I have a recollection I saw that Mariner supports A/B upgrade solution. But returning with interest, I cannot seem to retrace my steps where I saw this. So some questions around this topic....

1. Does Mariner support A/B upgrade?
2. Can the Image Build service generate a) raw disk images (efi+rootfs...) b) filesystem archives - i.e. efi content and seperate rootfs or /usr
3. If (1) == yes, then can you point me to the 'agent' that controls the download of N+1, identifies the target partition and then ultimately configures grub to boot into N+1 on subsequent reboot?
4. I'm curious - what I see as a build solution on github - is that the same code base you use to generate the published rpms/images, or do you use something more 'beefy' like for instance koji? If so - where could I go to mirror that build environment?
   warm regards
   Tom.