DNS Resolution Failing


Issue Summary

I have Redash installed with the AMI and am trying to connect to an RDS Aurora PostgreSQL instance. I’ve verified the security groups and networking are setup correctly. I get the following error:

Connection Test Failed:
could not translate host name "****.****.us-west-2.rds.amazonaws.com" to address: Temporary failure in name resolution

It looks like the /etc/resolve.conf is set to I check this

dig ****.****.us-west-2.rds.amazonaws.com

; <<>> DiG 9.11.3-1ubuntu1.1-Ubuntu <<>> ****.****.us-west-2.rds.amazonaws.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 57335
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

; EDNS: version: 0, flags:; udp: 65494
;****.****.us-west-2.rds.amazonaws.com. IN A

;; Query time: 0 msec
;; WHEN: Fri Mar 01 16:52:25 UTC 2019
;; MSG SIZE  rcvd: 87

and it looks fine. But then I check the psql port through telnet:

telnet ****.****.us-west-2.rds.amazonaws.com 5432
telnet: could not resolve ****.****.us-west-2.rds.amazonaws.com/5432: Temporary failure in name resolution

and get the same error I get from the application. Locally, it’s fine:

 telnet ****.****.us-west-2.rds.amazonaws.com 5432
Trying **.**.***.**...
Connected to ec2-**-**-***-**.us-west-2.compute.amazonaws.com.
Escape character is '^]'.

Even a ping to aws.amazon.com fails:

ping aws.amazon.com
ping: aws.amazon.com: Temporary failure in name resolution

Technical details:

  • Redash Version: 5.0.2+b5486
  • Browser/OS: Firefox / MacOSX
  • How did you install Redash: Amazon EC2 ( ami-0e164aeccb29a1be7 ) t2.medium