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  1. OpenShift Bugs
  2. OCPBUGS-10414

Incorrect domain resolution by the coredns/Corefile in Vsphere IPI Clusters | openshift-vsphere-infra


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      Description of problem:

      Coredns template implementations using incorrect Regex for resolving dot [.] character

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


      How reproducible:

      100% when you use router sharding with domains including apps

      Steps to Reproduce:

      1. Create an additional IngressRouter with domains names including apps. for ex: example.test-apps.<clustername>.<clusterdomain>
      2. Create and configure the external LB corresponding to the additonal IngressController 
      3. Configure the corporate DNS server and create records for the this additional IngressController resolving to the LB Ip setup in step 2 above.  
      4. Try resolving the additional domain routes from outside cluster and within cluster, the DNS resolution works fine fro outside cluster. However within cluster all additional domains consisting apps in the domain name resolve to the default ingress VIP instead of their corresponding LB IPs configured on the corportae DNS server.
      As an alternate and simple test to reroduce you can reproduce it simply by using the dig command on the cluster node with the additinal domain
      for ex: 
      sh-4.4# dig test.apps-test..<clustername>.<clusterdomain> 

      Actual results:

      DNS resolved all the domains consisting of apps to the defult Ingres VIP for example: example.test-apps.<clustername>.<clusterdomain> resolves to default ingressVIP instead of their actual coresponding LB IP.

      Expected results:

      DNS should resolve it to coresponding LB IP configured at the DNS server.

      Additional info:

      The DNS solution is happenng using the CoreFile Templates used on the node. which is treating dot(.) as character instead of actual dot[.] this is a Regex configuration bug inside CoreFile used on Vspehere IPI clusters.

            mkowalsk@redhat.com Mat Kowalski
            rhn-support-nkashyap Nirupma Nirupma
            Melvin Joseph Melvin Joseph
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