fix dns cache taking 30 mins to update

[Evrard-Nil]

No description provided.

[kvinwang]

Hardcoding google DNS seems unreasonable—users should be able to choose their preferred DNS server.
I'm curious about what's the root cause of the 30-minute cache issue.

[Leechael]

@Evrard-Nil Since dstack inherits the DNS resolver from systemd, do you think we can fix this by configuring systemd-resolved instead of forcing it to use a single DNS resolver? It's more like introducing another single point of failure.

[kvinwang]

Certbot simply waits for a fixed time (configurable via --dns-xxx-propagation-seconds), and there was a discussion on adding active polling. A better fallback approach would be adding a similar configuration parameter MAX_DNS_WAIT_SECONDS to cap the total duration of DNS active polling.