Uploaded image for project: 'OpenShift Bugs'
  1. OpenShift Bugs
  2. OCPBUGS-77026

DNS optimization, avoid NXDOMAIN errors

    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: Undefined Undefined
    • None
    • 4.20, 4.21
    • Management Console
    • None
    • None
    • False
    • Hide

      None

      Show
      None
    • None
    • None
    • None
    • None
    • None
    • None
    • None
    • None
    • None
    • None
    • None
    • None
    • None
    • None

      Description of problem:

      The Network Observability operator reports many NXDOMAIN errors in the openshift-console namespace. This is due to ambiguous DNS search queries, as explained here: https://github.com/openshift/runbooks/blob/master/alerts/network-observability-operator/DNSNxDomain.md#mitigation
      
      It does not result in visible issues (unless when seen with netobserv), however it means that the DNS traffic is not optimal, with several useless DNS queries being sent before eventually finding the one that is correctly resolved and working.
      
      It can be easily sorted out by adding a trailing dot to the DNS host, as explained in the runbook.

      Version-Release number of selected component (if applicable):

      Seen on 4.20
      Probably affecting all supported versions

      How reproducible:

      Always reproducible when a console plugin is installed

      Steps to Reproduce:

          1. Install netobserv operator 1.11 with DNSTracking feature
          2. Go to Observe > Network Health page
          3. Refresh the page a couple of times ; maybe wait 30 seconds and re-refresh
          

      Actual results:

      NetObserv shows "Too many DNS NX_DOMAIN errors" on namespace openshift-console

      Expected results:

      No DNS error

      Additional info:

      This is a very common DNS issue found in kubernetes workloads - not a severe one, since DNS resolution will eventually work, but still, suboptimal. 
      We had the same in netobserv: https://github.com/netobserv/network-observability-operator/pull/2227

              jtakvori Joel Takvorian
              jtakvori Joel Takvorian
              None
              None
              YaDan Pei YaDan Pei
              None
              Votes:
              0 Vote for this issue
              Watchers:
              3 Start watching this issue

                Created:
                Updated: