I was playing around with DNS Services for Services/pods, and encountered the following observation:
- Got two pods - check-ip and test2, in default and myns namespaces respectively.
- On checking the POD DNS resolution from inside check-ip pod, it seems that the DNS resolution is failing for
- nslookup test2-service-clusterip.myns
-
nslookup 10-244-1-3.test2-service-clusterip.myns.svc
But the resolution is working fine for the FQDN - 10-244-1-3.test2-service-clusterip.myns.svc.cluster.local
/usr/local/apache2 # nslookup 10-244-1-3.test2-service-clusterip.myns.svc.cluster.local
Server: 10.96.0.10
Address: 10.96.0.10:53
Name: 10-244-1-3.test2-service-clusterip.myns.svc.cluster.local
Address: 10.244.1.3
/usr/local/apache2 # nslookup 10-244-1-3.test2-service-clusterip.myns
Server: 10.96.0.10
Address: 10.96.0.10:53
** server can't find 10-244-1-3.test2-service-clusterip.myns: NXDOMAIN
** server can't find 10-244-1-3.test2-service-clusterip.myns: NXDOMAIN
/usr/local/apache2 # nslookup test2-service-clusterip
Server: 10.96.0.10
Address: 10.96.0.10:53
** server can't find test2-service-clusterip.svc.cluster.local: NXDOMAIN
** server can't find test2-service-clusterip.cluster.local: NXDOMAIN
** server can't find test2-service-clusterip.svc.cluster.local: NXDOMAIN
** server can't find test2-service-clusterip.default.svc.cluster.local: NXDOMAIN
** server can't find test2-service-clusterip.default.svc.cluster.local: NXDOMAIN
** server can't find test2-service-clusterip.cluster.local: NXDOMAIN
** server can't find test2-service-clusterip.ec2.internal: NXDOMAIN
** server can't find test2-service-clusterip.ec2.internal: NXDOMAIN
/usr/local/apache2 # nslookup test2-service-clusterip.myns
Server: 10.96.0.10
Address: 10.96.0.10:53
** server can't find test2-service-clusterip.myns: NXDOMAIN
** server can't find test2-service-clusterip.myns: NXDOMAIN
/usr/local/apache2 # nslookup test2-service-clusterip.myns.
Server: 10.96.0.10
Address: 10.96.0.10:53
** server can't find test2-service-clusterip.myns.: NXDOMAIN
** server can't find test2-service-clusterip.myns.: NXDOMAIN
/usr/local/apache2 # nslookup 10-244-1-3.test2-service-clusterip.myns.svc
Server: 10.96.0.10
Address: 10.96.0.10:53
** server can't find 10-244-1-3.test2-service-clusterip.myns.svc: NXDOMAIN
** server can't find 10-244-1-3.test2-service-clusterip.myns.svc: NXDOMAIN
- However, when I try to wget to either of the shortnames, it is resolving correctly and connecting.
/usr/local/apache2 # wget -O- http://test2-service-clusterip.myns
Connecting to test2-service-clusterip.myns (11.103.185.154:80)
writing to stdout
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
- 100% |*************************************************************************************************************| 615 0:00:00 ETA
written to stdout
I am curious as to whether this is a Httpd image issue with nslookup, or something that I am understanding incorrectly?