ovn-nbctl times out after 10s with 4+ machines

[Max Asnaashari]

When setting up MicroOVN with a LXD cluster, both using the `stable` channel snap, when LXD attempts to create the `ovn` network, it calls

```
ovn-nbctl --timeout=10 --db ssl:10.70.115.216:6641,ssl:10.70.115.137:6641,ssl:10.70.115.153:6641 -c /etc/ovn/cert_host -p /etc/ovn/key_host -C /etc/ovn/ovn-central.crt --wait=sb ha-chassis-group-add lxd-net2
```

with `ovn.env` from MicroOVN:
```
OVN_INITIAL_NB="10.70.115.216"
OVN_INITIAL_SB="10.70.115.216"
OVN_NB_CONNECT="ssl:10.70.115.216:6641,ssl:10.70.115.137:6641,ssl:10.70.115.153:6641"
OVN_SB_CONNECT="ssl:10.70.115.216:6642,ssl:10.70.115.137:6642,ssl:10.70.115.153:6642"
OVN_LOCAL_IP="10.70.115.137"
```

When there are 4 or more cluster members, this command occasionally times out after 10s which implies the network is unreachable:
```
Error: Failed to run: ovn-nbctl --timeout=10 --db ssl:10.70.115.216:6641,ssl:10.70.115.137:6641,ssl:10.70.115.153:6641 -c /etc/ovn/cert_host -p /etc/ovn/key_host -C /etc/ovn/ovn-central.crt --wait=sb ha-chassis-group-add lxd-net2: signal: alarm clock (2023-08-31T16:34:33Z|00003|fatal_signal|WARN|terminating with signal 14 (Alarm clock))
```

This might have to do with only 3 systems being present in `ovn.env` for the `CONNECT` strings, with the command occasionally being run on the excluded system, but I'm not sure.

[Frode Nordahl (fnordahl)]

The OVN central services are intentionally only ran on 3 of the nodes due to clustered DBs using the RAFT algorithm for consensus. Subsequently the NB/SB connect string will always only contain 3 IP addresses.

Any participating node without OVN central services will connect to all of the addresses in the connect string and depending on client settings, settle with the first one it hits or hunt for the leader.

Is there something in the deployment/environment preventing the client to connect to the nodes with OVN DB servers?

[Launchpad Janitor (janitor)]

[Expired for microovn because there has been no activity for 60 days.]