Recreate aiohttp session on connectivity check

It seems to actually get a proper connectivity check run, we need a new
vanilla ClientSession() object.

supervisor/coresys.py

@@ -63,7 +63,7 @@ def __init__(self):
 
         # External objects
         self._loop: asyncio.BaseEventLoop = asyncio.get_running_loop()
-        self._websession: aiohttp.ClientSession = aiohttp.ClientSession()
+        self._websession = None
 
         # Global objects
         self._config: CoreConfig = CoreConfig()
@@ -96,10 +96,8 @@ def __init__(self):
         self._bus: Bus | None = None
         self._mounts: MountManager | None = None
 
-        # Set default header for aiohttp
-        self._websession._default_headers = MappingProxyType(
-            {aiohttp.hdrs.USER_AGENT: SERVER_SOFTWARE}
-        )
+        # Setup aiohttp session
+        self.create_websession()
 
         # Task factory attributes
         self._set_task_context: list[Callable[[Context], Context]] = []
@@ -548,6 +546,16 @@ def run_in_executor(
 
         return self.loop.run_in_executor(None, funct, *args)
 
+    def create_websession(self) -> None:
+        """Create a new aiohttp session"""
+        if self._websession:
+            self.create_task(self._websession.close())
+
+        # Create session and set default header for aiohttp
+        self._websession: aiohttp.ClientSession = aiohttp.ClientSession(
+            headers=MappingProxyType({aiohttp.hdrs.USER_AGENT: SERVER_SOFTWARE})
+        )
+
     def _create_context(self) -> Context:
         """Create a new context for a task."""
         context = copy_context()

supervisor/host/network.py

@@ -296,6 +296,10 @@ async def apply_changes(
                     state = msg[0]
                     _LOGGER.debug("Active connection state changed to %s", state)
 
+                # This potentially updated the DNS configuration. Make sure the
+                # DNS plug-in picks up the latest settings.
+                await self.sys_plugins.dns.restart()
+
         # update_only means not done by user so don't force a check afterwards
         await self.update(force_connectivity_check=not update_only)
 

supervisor/supervisor.py

@@ -274,6 +274,8 @@ async def check_connectivity(self):
                 "https://checkonline.home-assistant.io/online.txt", timeout=timeout
             )
         except (ClientError, TimeoutError):
+            # Need to recreate the websession to avoid stale connection checks
+            self.coresys.create_websession()
             self.connectivity = False
         else:
             self.connectivity = True