remove mdns discovered peers from appearing in state

## Motivation

Running RDMA from source is not well documented as is. Several
surprising things that took time to debug internally too.

App should be updated to detect MacOS versions in future.

README.md

@@ -107,6 +107,10 @@ uv run exo
 
 This starts the exo dashboard and API at http://localhost:52415/
 
+
+*Please view the section on RDMA to enable this feature on MacOS >=26.2!*
+
+
 ### Run from Source (Linux)
 
 **Prerequisites:**
@@ -230,7 +234,7 @@ This removes:
 
 RDMA is a new capability added to macOS 26.2. It works on any Mac with Thunderbolt 5 (M4 Pro Mac Mini, M4 Max Mac Studio, M4 Max MacBook Pro, M3 Ultra Mac Studio).
 
-Note that on Mac Studio, you cannot use the Thunderbolt 5 port next to the Ethernet port.
+Please refer to the caveats for immediate troubleshooting.
 
 To enable RDMA on macOS, follow these steps:
 
@@ -247,6 +251,14 @@ To enable RDMA on macOS, follow these steps:
 
 After that, RDMA will be enabled in macOS and exo will take care of the rest.
 
+**Important Caveats**
+
+1. Devices that wish to be part of an RDMA cluster must be connected to all other devices in the cluster.
+2. The cables must support TB5.
+3. On a Mac Studio, you cannot use the Thunderbolt 5 port next to the Ethernet port.
+4. If running from source, please use the script found at `tmp/set_rdma_network_config.sh`, which will disable Thunderbolt Bridge and set dhcp on each RDMA port.
+5. RDMA ports may be unable to discover each other on different versions of MacOS. Please ensure that OS versions match exactly (even beta version numbers) on all devices.
+
 ---
 
 ### Using the API

src/exo/main.py

@@ -90,7 +90,6 @@ class Node:
             worker = Worker(
                 node_id,
                 session_id,
-                connection_message_receiver=router.receiver(topics.CONNECTION_MESSAGES),
                 global_event_receiver=router.receiver(topics.GLOBAL_EVENTS),
                 local_event_sender=router.sender(topics.LOCAL_EVENTS),
                 command_sender=router.sender(topics.COMMANDS),
@@ -227,9 +226,6 @@ class Node:
                         self.worker = Worker(
                             self.node_id,
                             result.session_id,
-                            connection_message_receiver=self.router.receiver(
-                                topics.CONNECTION_MESSAGES
-                            ),
                             global_event_receiver=self.router.receiver(
                                 topics.GLOBAL_EVENTS
                             ),

src/exo/worker/main.py

@@ -7,7 +7,6 @@ from anyio import CancelScope, create_task_group, fail_after
 from anyio.abc import TaskGroup
 from loguru import logger
 
-from exo.routing.connection_message import ConnectionMessage, ConnectionMessageType
 from exo.shared.apply import apply
 from exo.shared.models.model_cards import ModelId
 from exo.shared.types.api import ImageEditsInternalParams
@@ -57,7 +56,6 @@ class Worker:
         node_id: NodeId,
         session_id: SessionId,
         *,
-        connection_message_receiver: Receiver[ConnectionMessage],
         global_event_receiver: Receiver[ForwarderEvent],
         local_event_sender: Sender[ForwarderEvent],
         # This is for requesting updates. It doesn't need to be a general command sender right now,
@@ -74,7 +72,6 @@ class Worker:
         self.event_index_counter = event_index_counter
         self.command_sender = command_sender
         self.download_command_sender = download_command_sender
-        self.connection_message_receiver = connection_message_receiver
         self.event_buffer = OrderedBuffer[Event]()
         self.out_for_delivery: dict[EventId, ForwarderEvent] = {}
 
@@ -105,7 +102,6 @@ class Worker:
             tg.start_soon(info_gatherer.run)
             tg.start_soon(self._forward_info, info_recv)
             tg.start_soon(self.plan_step)
-            tg.start_soon(self._connection_message_event_writer)
             tg.start_soon(self._resend_out_for_delivery)
             tg.start_soon(self._event_applier)
             tg.start_soon(self._forward_events)
@@ -279,41 +275,6 @@ class Worker:
         instance = self.state.instances[task.instance_id]
         return instance.shard_assignments.node_to_runner[self.node_id]
 
-    async def _connection_message_event_writer(self):
-        with self.connection_message_receiver as connection_messages:
-            async for msg in connection_messages:
-                await self.event_sender.send(
-                    self._convert_connection_message_to_event(msg)
-                )
-
-    def _convert_connection_message_to_event(self, msg: ConnectionMessage):
-        match msg.connection_type:
-            case ConnectionMessageType.Connected:
-                return TopologyEdgeCreated(
-                    conn=Connection(
-                        source=self.node_id,
-                        sink=msg.node_id,
-                        edge=SocketConnection(
-                            sink_multiaddr=Multiaddr(
-                                address=f"/ip4/{msg.remote_ipv4}/tcp/{msg.remote_tcp_port}"
-                            ),
-                        ),
-                    ),
-                )
-
-            case ConnectionMessageType.Disconnected:
-                return TopologyEdgeDeleted(
-                    conn=Connection(
-                        source=self.node_id,
-                        sink=msg.node_id,
-                        edge=SocketConnection(
-                            sink_multiaddr=Multiaddr(
-                                address=f"/ip4/{msg.remote_ipv4}/tcp/{msg.remote_tcp_port}"
-                            ),
-                        ),
-                    ),
-                )
-
     async def _nack_request(self, since_idx: int) -> None:
         # We request all events after (and including) the missing index.
         # This function is started whenever we receive an event that is out of sequence.

tmp/set_rdma_network_config.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+PREFS="/Library/Preferences/SystemConfiguration/preferences.plist"
+
+# Remove bridge0 interface
+ifconfig bridge0 &>/dev/null && {
+  ifconfig bridge0 | grep -q 'member' && {
+    ifconfig bridge0 | awk '/member/ {print $2}' | xargs -n1 ifconfig bridge0 deletem 2>/dev/null || true
+  }
+  ifconfig bridge0 destroy 2>/dev/null || true
+}
+
+# Remove Thunderbolt Bridge from VirtualNetworkInterfaces in preferences.plist
+/usr/libexec/PlistBuddy -c "Delete :VirtualNetworkInterfaces:Bridge:bridge0" "$PREFS" 2>/dev/null || true
+
+networksetup -listlocations | grep -q exo || {
+  networksetup -createlocation exo
+}
+
+networksetup -switchtolocation exo
+networksetup -listallhardwareports \
+  | awk -F': ' '/Hardware Port: / {print $2}' \
+  | while IFS=":" read -r name; do
+      case "$name" in
+        "Ethernet Adapter"*)
+                ;;
+        "Thunderbolt Bridge")
+                ;;
+        "Thunderbolt "*)
+          networksetup -listallnetworkservices \
+            | grep -q "EXO $name" \
+              || networksetup -createnetworkservice "EXO $name" "$name" 2>/dev/null \
+              || continue
+          networksetup -setdhcp "EXO $name"
+                ;;
+        *)
+          networksetup -listallnetworkservices \
+            | grep -q "$name" \
+              || networksetup -createnetworkservice "$name" "$name" 2>/dev/null \
+              || continue
+                ;;
+      esac
+    done
+
+networksetup -listnetworkservices | grep -q "Thunderbolt Bridge" && {
+  networksetup -setnetworkserviceenabled "Thunderbolt Bridge" off
+} || true