[jboss-jira] [JBoss JIRA] (JGRP-2363) DNS Ping cannot lookup SRV record for service port

DNS Ping cannot lookup SRV record for service port -------------------------------------------------- Key: JGRP-2363 URL: https://issues.redhat.com/browse/JGRP-2363 Project: JGroups Issue Type: Bug Affects Versions: 4.0.20 Reporter: Howard Gao Assignee: Bela Ban Priority: Major Attachments: App2.java I've got a problem regarding getting service port in DNS_PING DNS lookup. It seems in my openshift environment the JNDI DNS lookup cannot query the correct SRV record from the openshift DNS server. Ref: https://github.com/jboss-openshift/openshift-ping/blob/1.2.1.Final/dns/sr... For example, here is the ping service: apiVersion: v1 kind: Service metadata: annotations: description: The JGroups ping port for clustering. service.alpha.kubernetes.io/tolerate-unready-endpoints: 'true' labels: application: application0 template: amq-broker-73-persistence-clustered xpaas: 1.4.16 name: application0-ping spec: clusterIP: None publishNotReadyAddresses: true ports: port: 8888 protocol: TCP name: jgroup-port targetPort: 8888 selector: deploymentConfig: application0-amq After it is deployed I deployed a application pod with JGroups DNS_PING protocol loaded. The relevant jgroups xml part looks like this: <config> ... <openshift.DNS_PING timeout="3000" serviceName="application0-ping" /> ... </config> After my application pod is in running state, I checked the log and there is a warning message from DNS_PING: 2019-07-22 04:16:59,600 INFO [org.openshift.ping.common.Utils] 3 attempt(s) with a 1000ms sleep to execute [GetServicePort] failed. Last failure was [java.lang.NullPointerException: null] 2019-07-22 04:16:59,601 WARNING [org.jgroups.protocols.openshift.DNS_PING] No DNS SRV record found for service [application0-ping] After some debugging it turns out that the DNS lookup for the record by this name "_tcp.application0-ping" returned null. However if I logged into the application pod and do nslookup it will give me correct record: sh-5.0# nslookup -type=srv _tcp.application0-ping Server: 10.74.177.77 Address: 10.74.177.77#53 _tcp.application0-ping.default.svc.cluster.local service = 10 100 8888 44c84e52.application0-ping.default.svc.cluster.local. And you can get the full name from the record, which is _tcp.application0-ping.default.svc.cluster.local If I then pass the full qualified name into the application and it can query the SRV record successfully. I have no idea why my application can't query the record using the short form name (i.e. _tcp.application0-ping). Could it be some configuration issue for the DNS ping? My openshift env details are: oc v3.11.117 kubernetes v1.11.0+d4cacc0 features: Basic-Auth GSSAPI Kerberos SPNEGO and the java version used in pod: sh-5.0# java -version openjdk version "1.8.0_212" OpenJDK Runtime Environment (build 1.8.0_212-b04) OpenJDK 64-Bit Server VM (build 25.212-b04, mixed mode) and the base OS is fedora 30.