drop the AX51 experiment but keep documentation

  the following settings:

  * Server: [PX62-NVMe](https://www.hetzner.com/dedicated-rootserver/px62-nvme?country=OTHER)

    Note: we are also experimenting with the new AX line

    ([AX51-NVMe](https://www.hetzner.com/dedicated-rootserver/ax51-nvme?country=OTHER)) but in the past DSA had problems live-migrating

    (it wouldn't immediately fail but there were "issues" after). So

    we might need to [failover](http://docs.ganeti.org/ganeti/2.15/man/gnt-instance.html#failover) instead of migrate between those

    parts of the cluster.

  * Location: `FSN1`

  * Operating system: Rescue

  * Additional drives: 2x10TB

- Prepare all the nodes by configuring them in puppet.  They should be in the class `roles::ganeti::fsn` if they

  are part of the fsn cluster.  If you make a new cluster, make a new role and add nodes.

## New Master

Note: we considered experimenting with the new AX line

([AX51-NVMe](https://www.hetzner.com/dedicated-rootserver/ax51-nvme?country=OTHER)) but in the past DSA had problems live-migrating (it

wouldn't immediately fail but there were "issues" after). So we might

need to [failover](http://docs.ganeti.org/ganeti/2.15/man/gnt-instance.html#failover) instead of migrate between those parts of the

cluster. There are also doubts that the Linux kernel supports those

shiny new processors at all: similar processors had [trouble booting

before Linux 5.5](https://www.phoronix.com/scan.php?page=news_item&px=Threadripper-3000-MCE-5.5-Fix) for example, so it might be worth waiting a

little before switching to that new platform, even if it's

cheaper. See the cluster configuration section below for a larger

discussion of CPU emulation.

## New cluster

To create the fsn master, we added fsngnt to DNS, then ran