Why are there disconnects seemingly at random?

[Zitronenjoghurt]

I have recently looked into my bots logs and noticed that theres 2 scenarios where it reconnects.

The first one seems to be intended as it sends a reconnect opcode.

discord.gateway For Shard ID None: WebSocket Event: {'t': None, 's': None, 'op': 7, 'd': None}
discord.gateway Received RECONNECT opcode.

But sometimes theres also this:

discord.gateway Received WSMessage(type=<WSMsgType.CLOSED: 257>, data=None, extra=None)

after which theres usually an error like:

discord.gateway Websocket closed with WSCloseCode.OK, cannot reconnect.
discord.client Dispatching event disconnect
discord.client Attempting a reconnect in 1.64s
Traceback (most recent call last):
  File "/home/user/Bots/BotName/venv/lib/python3.10/site-packages/discord/client.py", line 659, in connect
    await self.ws.poll_event()
  File "/home/user/Bots/BotName/venv/lib/python3.10/site-packages/discord/gateway.py", line 646, in poll_event
    raise ConnectionClosed(self.socket, shard_id=self.shard_id, code=code) from None
discord.errors.ConnectionClosed: Shard ID None WebSocket closed with 1000

It does automatically reconnect afterwards but Im just wondering what the reason is for discord to close the connection without asking for a reconnect. Is it a normal thing to happen? In the end its handled well and you dont notice it, though it still throws an error which shouldnt normally happen on a regular basis.

[Rapptz]

This is just part of the connection flow. Discord disconnects clients every 15 minutes to 2 hours for load balancing reasons. Some of those rarely get invalidated and you have to do a full reconnect but most of the time it's just resumed properly.