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  1. 10_11/


Go's Mac builders run at Mac hosting provider, MacStadium. We have a VMware cluster with 8 physical Mac Pros on which we run two VMs each. There is also a single M1 Mac Mini.

In addition to the Mac VMs and M1 Mac mini, we also run one a Linux VM that's our bastion host & runs various services.

Bastion Host

The bastion host is and can be accessed via:

$ ssh -D :1080 -i ~/keys/id_ed25519_golang1

(Where id_ed255519_golang1 is available from go/go-builders-ssh)

It also runs:

  • a DHCP server for the 16 Mac VMs to get IP addresses from (systemd unit isc-dhcp-server.service, so watch with journalctl -f -u isc-dhcp-server.service)

  • the makemac daemon daemon (systemd unit makemac.service, so watch with journalctl -f -u makemac). This monitors the build coordinator ( as well as the VMware cluster (via the govc CLI tool) and makes and destroys Mac VMs as needed. It also serves plaintext HTTP status at which used to be accessible in a browser, but recent HSTS configuration on * means you need to use curl now. But that‘s a good way to see what it’s doing remotely, without authentication.

  • WireGuard listening on port 51820, because OpenVPN + Mac‘s built-in VPN client is painful and buggy. See config in /etc/wireguard/wg0.conf. This doesn’t yet come up on boot. It's a recent addition.


The method of last resort to access the cluster, which works even if the bastion host VM is down, is to VPN to our Cisco gateway via go/go-how-to-vpn-into-macstadium.

VMware web UI

Connect with OpenVPN, WireGuard, or configure your browser to use localhost:1080 as a SOCKS proxy. Add:

to your hosts file, then access the UI at

VMware web UI at:

Adding a New Image

When a new version of macOS is released:

  • Ensure that the version of vSphere deployed on MacStadium supports the new version of macOS. If it doesn't, either request that MacStadium upgrade the cluster or seek guidance from them about the upgrade path.

  • Clone the latest macOS version on vSphere and upgrade that version to the desired macOS version as per the instructions.

  • If a completely new image is required, follow the images setup notes in order to add a new image.


Common techniques to debug: