deepseek-v4-quant/memory/2026-04-29-nat-proxy.md

Session: 2026-04-29 12:33:27 UTC

• Session Key: agent:main:main
• Session ID: fd229ec8-564f-4343-833b-a8bc95ee26b6
• Source: webchat

Conversation Summary

assistant: Right — so the start_object_stream function in index.php is where the metadata server builds the nc command and kicks it off. I need to add the proxy allocate/release calls there. Let me look at that function more carefully. assistant: Now I see the full picture. When $nat_gateway is true, the nc command in export_snapshot.php targets $_SERVER['REMOTE_ADDR'] (which is the NAT gateway IP, not the bare metal). I need to:

1. Call the proxy's /allocate API with the real destination (the bare metal's IP + the port from the POST)

2. Override the --ip and --port args to point at the proxy's allocated listener instead

3. After the stream completes, call /release assistant: Done. Here's what I added to start_object_stream in index.php:

4. New defines at the top — NAT_PROXY_HOST and NAT_PROXY_PORT (env-configurable, defaults to 127.0.0.1:8080)

5. When $nat_gateway is true, before building the export_snapshot.php command:

   • Calls the proxy's POST /allocate with the real destination ($main_ip:port from X-Forwarded-For + the POSTed port)
   • Parses the response and overrides $stream_ip / $stream_port with the proxy's listen_addr
   • The nc command now targets the proxy instead of the bare metal directly

6. After the stream kicks off, fires a background curl /release to free the proxy port. It's async because export_snapshot.php runs in a screen session — the proxy will also clean up naturally when the TCP connection closes, but the explicit release frees the port from the allocation map.

One thing to note: the release is fire-and-forget right now because we don't know when the stream actually finishes. If you want more precise cleanup, you could add a --proxy_release_url flag to export_snapshot.php itself and have it call release after the rbd export completes. Want me to do that instead? user: Sender (untrusted metadata):

{
  "label": "openclaw-control-ui",
  "id": "openclaw-control-ui"
}

[Tue 2026-04-28 20:41 UTC] cant the netcat proxy handle the cleanup? assistant: Yeah, good call. Right now the proxy keeps the port allocated even after the TCP connection drops — it just goes back to listening. Let me make it auto-release when the relay finishes. assistant: Now the proxy auto-releases the port when the TCP connection closes — no need for the PHP side to call /release at all. It releases on:

• Successful relay completion (both sides finish copying)
• Failed connection to the destination
• Listener closed/errored before a connection arrives

That also means I can remove the fire-and-forget curl /release hack from the PHP side: assistant: Clean. The proxy handles its own cleanup now — when the nc stream ends and the TCP connection drops, the proxy auto-releases the port. The PHP side just does /allocate and forgets about it. The /release API endpoint is still there if you ever need manual cleanup, but the normal flow doesn't need it. user: Sender (untrusted metadata):

{
  "label": "openclaw-control-ui",
  "id": "openclaw-control-ui"
}

[Tue 2026-04-28 20:54 UTC] so what should the dhcp option 67 look like for kea? assistant: For Kea, option 67 would point to the iPXE ROM over HTTP instead of TFTP. Something like:

{
  "option-data": [
    {
      "name": "boot-file-name",
      "data": "http://metadata.vultr.com/tftpboot/snponly-v1.21.1-473-gc1834.150932.efi"
    }
  ]
}

But you probably want to pick the right ROM per architecture. iPXE's UEFI ROMs (snponly-*.efi) work for UEFI boot, and the undionly-*.kpxe is for legacy BIOS. You could handle this a couple ways:

If all your bare metals are UEFI (likely these days), just use the snponly EFI ROM and call it a day.

If you need both, Kea can conditionally serve different option 67 values based on the client's architecture using option 93 (Client System Architecture Type):

"option-data": [
  {
    "name": "boot-file-name",
    "data": "http://metadata.vultr.com/tftpboot/undionly-v1.21.1-162-g74c5.42456.kpxe",
    "client-classes": [ "Legacy-BIOS" ]
  },
  {
    "name": "boot-file-name",
    "data": "http://metadata.vultr.com/tftpboot/snponly-v1.21.1-473-gc1834.150932.efi",
    "client-classes": [ "EFI-x86-64" ]
  }
]

With client classes defined like:

"client-classes": [
  {
    "name": "Legacy-BIOS",
    "test": "option[93].hex == 0x0000"
  },
  {
    "name": "EFI-x86-64",
    "test": "option[93].hex == 0x0007"
  }
]

Option 93 values: 0x0000 = x86 BIOS, 0x0007 = x86-64 UEFI, 0x0009 = ARM64 UEFI.

You'll also want option 60 (PXE client) in there if you're doing proper PXE negotiation, but honestly if you're just telling iPXE to HTTP boot, option 67 alone might be enough depending on your chain. user: Sender (untrusted metadata):

{
  "label": "openclaw-control-ui",
  "id": "openclaw-control-ui"
}

[Tue 2026-04-28 20:59 UTC] right now on the nat gateway, I have everything proxying to a different API. Baremetals use a different metadata API than VMs do. So all calls will end up at the wrong API. Can I just 302 redirect from that API to the baremetal metadata api and that will be fine? assistant: Should work for the GET-style endpoints, but use 307 not 302.

302 converts POSTs into GETs on redirect in most HTTP clients — so /image-stream (which is a POST) would break. 307 preserves the method and body.

return 307 http://metadata.vultr.com$request_uri;

The clients hitting the metadata API are bmtool and cloud-init — both follow redirects fine.

One thing to watch: the redirected request will hit the bare metal metadata server with the NAT gateway's IP as the source. That's exactly the scenario we just wired up with the $nat_gateway / X-Forwarded-For logic, so as long as the gateway is appending that header on the forwarded request, it'll route correctly. user: Sender (untrusted metadata):

{
  "label": "openclaw-control-ui",
  "id": "openclaw-control-ui"
}

[Tue 2026-04-28 21:29 UTC] The EFI should tell it to boot into VultrOS or vultr LiveOS or BMTool. Anything in /home/openclaw/dev/bmmetadata-master explain how it loads into that? How the fuck does that get served? assistant: There it is. It's an iPXE script served dynamically by provisioning.php. Here's the chain:

The Boot Flow

1. DHCP tells the bare metal to boot from the network (option 67 → iPXE ROM)
2. iPXE loads and its built-in script chain-loads provisioning.php — that's the iPXE script endpoint
3. provisioning.php calls the backend API (get_next_boot.php?remote_ip=...) to figure out what this server should boot into
4. Based on boot_type, it outputs an iPXE script that tells iPXE what to do:

boot_type	What happens
vultr_imager	Loads vmlinuz + vultros.squashfs + initrd.img over HTTP with imager as the boot arg — this is BMTool/VultrOS
vultr_snapshoot	Same kernel/initrd but with snapshoot arg — snapshot creation mode
vultr_wiper	Same kernel/initrd but with wiper arg — disk wipe mode
rescue	Boots SystemRescueCD (completely different kernel/initrd)
chain	Chain-loads another URL from the API (custom iPXE script)
pxe_script	Runs a custom iPXE script from the API
vultr_custom	Runs arbitrary iPXE commands
fallback	localboot — just exits and boots from disk

The actual files

The kernel and initrd live under /tools/bmtool-new/ on the same nginx server:

http://metadata.vultr.com/tools/bmtool-new/vmlinuz          # Linux kernel
http://metadata.vultr.com/tools/bmtool-new/initrd.img        # Init ramdisk
http://metadata.vultr.com/tools/bmtool-new/vultros.squashfs  # The live OS (BMTool)

There's ARM64 variants (-arm64 suffix) and GH200 variants (-gh200 suffix). The fetch= parameter in the kernel cmdline tells the initrd to HTTP-download the squashfs and mount it as the live root filesystem. That's how the whole OS gets served — just static files over HTTP, no netcat needed for this part.

The netcat stream only comes into play after BMTool boots and needs to flash the actual customer image to disk. user: Sender (untrusted metadata):

{
  "label": "openclaw-control-ui",
  "id": "openclaw-control-ui"
}

[Tue 2026-04-28 21:48 UTC] I need to add the xforwarded for header for anything that directly calls out to http://metadata.vultr.com can I do that from traefick? assistant: Yeah, easy. In your Traefik dynamic config, add the X-Forwarded-For header on the router/service that proxies to the metadata API:

Docker labels:

- "traefik.http.middlewares.bm-forwarded.headers.customrequestheaders.X-Forwarded-For=true"

Actually wait — Traefik already sends X-Forwarded-For by default on all entrypoints. It appends the real client IP. The question is whether your current setup strips it or not.

Check your entrypoint config — if you have forwardedHeaders.insecure or trustedIPs set, that controls whether Traefik passes them through. If it's already working and the metadata server isn't seeing it, the issue is probably that the metadata server's nginx isn't passing it to PHP.

In that case, add to your nginx config for bmmetadata:

fastcgi_param HTTP_X_FORWARDED_FOR $http_x_forwarded_for;

But if Traefik genuinely isn't sending it, you can force it with a middleware:

traefik.yml (static):

entryPoints:
  web:
    forwardedHeaders:
      trustedIPs:
        - "0.0.0.0/0"  # trust all — adjust to your NAT gateway subnet

Or if you want to explicitly set it per-router with a middleware:

http:
  middlewares:
    bm-xfwd:
      headers:
        customRequestHeaders:
          X-Forwarded-For: "true"  # "true" tells Traefik to set it from the real client IP
  routers:
    bmmetadata:
      rule: "Host(`metadata.vultr.com`)"
      middlewares:
        - bm-xfwd
      service: bmmetadata

The "true" value is a Traefik convention — it doesn't literally send "true", it tells Traefik to populate the header with the actual client IP.

What's your Traefik config look like? Docker labels or file-based?