On Thursday we will be upgrading the network infrastructure that routes network traffic for all cloud-vps and toolforge networking. This will involve at least one failover between hosts, which will interrupt existing network connections.
There should not be a prolonged network outage, but some connections will be reset. If your tools or services are not resilient to unexpected disconnections, you may need to manually restart services after the updates are complete.
The changeover will happen sometime between 14:00 and 15:00 UTC this coming Thursday. Details about this can be found at https://phabricator.wikimedia.org/T253124
-Andrew + the WMCS team