[Bug 1668771] Re: systemd-resolved negative caching for extended period of time

[James Hebden]

This is especially upsetting in an OpenStack and server environment
where external DNS is being used to reach/resolve API endpoints and
other systems such as database servers. A small outage to DNS becomes a
potentially unbounded outage when the SERVFAIL responses are cached
indefinitely, requiring manual intervention on each host in addition to
fixing the cause of the SERVFAIL.

** Tags added: canonical-bootstack

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https://bugs.launchpad.net/bugs/1668771

Title:
  systemd-resolved negative caching for extended period of time

Status in systemd:
  New
Status in systemd package in Ubuntu:
  Confirmed

Bug description:
  231-9ubuntu3

  If a DNS lookup returns SERVFAIL, systemd-resolved seems to cache the
  result for very long (infinity?). I have to restart systemd-resolved
  to have the negative caching purged.

  After SERVFAIL DNS server issue has been resolved, chromium/firefox
  still returns DNS error despite host can correctly resolve the name.

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