Sharing is caring - Thor Thunder Tigress Platform

A friend wants time on the Thor’s GPU and somewhere to host the small apps they write, with their own domain. This chapter is the design. None of it is built yet. When we build it, the work is an afternoon.

This chapter covers

the name a visitor sees in the address bar, and the two ways to change it
two logins on one machine, and what sudo gives a second person here
sharing the node over Tailscale
one Tailscale name carrying several apps, through paths and ports
why their domain cannot point at Funnel directly
the one GPU, shared with the models
what tends to go wrong, and the order to do the work in

The shape of it

Your friend gets a login on the Thor. They reach it over the tailnet, the network your own machines use, so no port is opened at home. Their apps run as them, from their home directory, on ports from a range the two of you agree on. Public apps go out through Tailscale Funnel; private ones stay on the tailnet.

Figure 1 One machine, two logins, one GPU.

The name a visitor sees

The node is called arpanpathak because that is the Thor’s hostname, and Funnel serves the name the node has. An app published on Funnel gets that name in its address.

Both parts of the name can be changed:

The machine name, the arpanpathak part. Admin console → Machines → the Thor → Edit machine name. Untick “Auto-generate from OS hostname” so it stays fixed, then type the new name. From the CLI, sudo tailscale set --hostname=thor-tigress. It has to be unique in the tailnet.
The tailnet name, the taildb9a39 part, shared by every device you own. Admin console → DNS → Tailnet DNS name → Rename tailnet. Tailscale offers randomly generated names such as cat-crocodile, so this part cannot be typed. After a random name has issued certificates you can switch between it and the original string, and no further.

Changing the machine name moves every service on the node. The chat answers at arpanpathak.taildb9a39.ts.net, the forwarding page at voltforge.tech sends visitors there, the Claude Code and openBatarangs aliases use it, and about.html, jetson-thor/README.md and this book quote it. After a rename the old address stops answering, Funnel has to be brought up again on the new name, the certificate is reissued, and saved links and --openai-url values need updating. Chapter “Operations” has the steps and a script that carries the change through the forwarding page and this repository. Do the rename when you want a neutral name for the whole platform, and while no app of theirs is on the node.

A node of their own

If only their links need a name that is not yours, put a second node in front of their apps. Funnel runs on that node. Their app keeps running on the Thor, which that node reaches over the tailnet as a shared node.

Two ways to have it:

A machine of theirs: an always-on box or a small VPS, signed into their own Tailscale account. Their tailnet, their Funnel, their certificates, their domain. It runs a short proxy to the Thor and does not use the GPU.
A second node on the Thor: a container or a small VM with its own tailscaled, signed into their account. No extra hardware, but two Tailscale instances on one host is more to keep working.

A visitor reaches app.example.com, which lands on a Tailscale node of their own running Funnel and a proxy. That node reaches the Thor over the tailnet, where their app listens on 127.0.0.1:9100. The Thor's own name does not change. — **Figure 2** Their node in front, the Thor behind it.

A visitor sees	What it costs	What changes here
`app.example.com`, or the ts.net name of their node	a machine of theirs, or a container on the Thor	nothing
`thor-tigress.…ts.net/friend-app`	free	the node is renamed; the chat’s address and saved links move
`app.example.com`, then your ts.net name after the redirect	free	nothing; the address bar shows your name after the redirect

Two logins

They get their own Unix user: their home, their SSH key, their files. No shared password, no shared home directory. They also get sudo and the video and render groups, which CUDA needs before it will see the GPU.

With sudo they can read every file on the machine, stop any service and install anything. On this box that means:

Thing	With sudo
`~/Projects`, `~/models`	readable
`~/.config/thor-chat/api-key`	readable; file permissions are the only protection
`~/.ssh/id_ed25519`	readable, unless the key has a passphrase
`~/.config/thor-chat/keyring`	readable, but the records inside need your passphrase
`thor-chat`, `thor-edge-llm`, `thor-tigress-agent`, `searxng`	they can stop or restart them

The SSH key is worth settling first. If it has no passphrase and other machines trust it, a copy of the file is a copy of your access to those machines. Adding a passphrase, or generating a separate key for the Thor, takes ten minutes.

The keyring needs your passphrase to open, so the records inside it stay yours. Nothing in this design puts their apps in front of your services.

Reaching it

Tailscale shares one node with another account. In the admin console the Thor’s row has a Share button; the invite link goes to their Tailscale account. They accept it and the Thor appears in their machine list, marked as shared. They get the Thor and nothing else: not your other machines, and you do not see theirs.

The node answers at 100.84.254.65, which is arpanpathak in the tailnet’s DNS today. The build steps change that name before any of their apps exist.

ssh friend@100.84.254.65

sshd is already listening on 22, and the tailnet is the way in. If the tailnet has an ACL file that restricts who may reach this node, add a rule for the sharing relationship and test it before handing over the key.

One setting saves both of you password prompts:

sudo tailscale set --operator=friend

After that, tailscale serve and tailscale funnel work for their user and yours.

Their apps, and the paths they live on

The node has one Tailscale name and one certificate for it. Funnel answers on that name, on the three ports it may use: 443, 8443 and 10000. Your chat holds the root path on 443.

Their app listening on 127.0.0.1:9100 becomes reachable as

tailscale serve --bg --https=8443 9100              # their tailnet only
tailscale funnel --bg --set-path=/friend-app 9100   # public, on 443

The first stays private, to devices allowed to reach this node. The second is open to anyone with the address. The path or the port chooses the app. Each command replaces the node’s whole serve config, so check before changing it:

tailscale serve status

A change made without looking can drop the other person’s path.

Three ways into the Thor. Anyone on the internet reaches your chat at the root path. Their domain goes through a forwarding page to the friend-app path. Their own devices reach the same app privately on port 8443 with tailscale serve. — **Figure 3** One name, one certificate; the path or the port picks the app.

Two more details. Their apps bind to 127.0.0.1 rather than 0.0.0.0, so the tailnet and Funnel remain the only ways in. And a systemctl --user unit stops when they log out unless someone runs

sudo loginctl enable-linger friend

once.

Their domain

A CNAME from app.example.com to thor-tigress.cat-crocodile.ts.net does not work. The browser asks for app.example.com, Funnel answers with a certificate for thor-tigress.cat-crocodile.ts.net, and the names do not match. Funnel serves the node’s own name and no other.

If they run a node of their own, their domain points at that node and the question does not arise. Otherwise there are two options:

Option	Address bar	Notes
forwarding page on a public host	their domain, then the ts.net name after the redirect	free; the bar changes on the way
a small public proxy of theirs, with the Thor behind it	their domain throughout	a machine to patch, and it sees their traffic

Chapter “Bring your own domain” has the Namecheap and GitHub steps for the forwarding page, and the same ones work for them.

The one GPU

There is one NVIDIA Thor GPU in the box, 128 GB of unified memory. The chat keeps a large part of it warm: thor-chat is llama-server with Nemotron, and thor-edge-llm is Qwen. This hardware has no MIG, so the GPU is shared by time rather than partitioned.

nvidia-smi shows who holds memory.
sudo systemctl stop thor-chat thor-edge-llm frees the GPU, and start brings the chat back in about a minute. They can do both, so agree on when.
The power mode and jetson_clocks are machine-wide and affect both of you.
Disk is shared. 742 GB is free now, and one dataset can fill most of it.

What can go wrong

They reboot the Thor while the chat is serving. The services come back; the requests in flight do not.
You both edit tailscale serve, and one path disappears.
An app bound to 0.0.0.0 is reachable from places neither of you intended.
A public Funnel path is public. If their app has a login, that login is on the internet.
GPU memory runs out under one process because the other took it.

The order we would do it

Settle the name. A node of theirs leaves your addresses alone; renaming the machine moves every service on it. If you rename, do it while no app of theirs is on the node.
sudo adduser --disabled-password friend; add them to sudo, video and render; put their public key in ~/.ssh/authorized_keys, with .ssh at mode 700 and the file at 600.
sudo tailscale set --operator=friend and sudo loginctl enable-linger friend.
Share the Thor with their Tailscale account from the admin console. They accept and try ssh friend@100.84.254.65.
They write one small app, bind it to 127.0.0.1:9100, and run it from a systemctl --user unit.
tailscale serve --bg --https=8443 9100 first, so it is reachable and private. Funnel when they want it public.
Their own node or proxy, if the address matters, then the DNS record.
Write the result back into this chapter: the commands that worked, the ports, the name, and the numbers.

Settle the SSH key question before step 1.

Keyboard shortcuts

Thor Thunder Tigress Platform