In environments with many desktops where some DNS queries time out,
we can run in to situations where the discovery loop doesn't complete
before the desktop's 10m TTL expires, causing desktops to disappear
and reappear sporadically.
- Increase the TTL for LDAP-discovered desktops to 30m. This won't
harm UX, since desktops that stop being discovered are already
purged prior to their expiration.
- Perform both DNS queries (via the default resolver and by hitting
the LDAP server directly) in parallel. This reduces the maximum
time a single lookup can take from 20s to 5s.
Zac Bergquist
e64597718e