The EC2 plugin is currently throwing the following error while trying to launch a build slave:
Jan 19, 2015 5:55:48 PM hudson.plugins.ec2.EC2Cloud provision
WARNING: Failed to count the # of live instances on EC2
com.amazonaws.AmazonClientException: Unable to execute HTTP request: eu-central-1.ec2.amazonaws.com: Name or service not known
Performing a resolve directly against the SOA nameservers results in no answer:
dig eu-central-1.ec2.amazonaws.com @r1.amazonaws.com
; <<>> DiG 9.9.2-P2 <<>> eu-central-1.ec2.amazonaws.com @r1.amazonaws.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33907
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 6, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;eu-central-1.ec2.amazonaws.com. IN A
;; AUTHORITY SECTION:
ec2.amazonaws.com. 907 IN NS ns-911.amazon.com.
ec2.amazonaws.com. 907 IN NS ns-912.amazon.com.
ec2.amazonaws.com. 907 IN NS ns-921.amazon.com.
ec2.amazonaws.com. 907 IN NS ns-923.amazon.com.
ec2.amazonaws.com. 907 IN NS ns-941.amazon.com.
ec2.amazonaws.com. 907 IN NS ns-942.amazon.com.
;; Query time: 25 msec
;; SERVER: 188.8.131.52#53(184.108.40.206)
;; WHEN: Mon Jan 19 17:57:13 2015
;; MSG SIZE rcvd: 192
The AWS API docs specify EC2 hostnames like the following:
So, the "ec2" and "eu-central-1" portions are flipped. I recommend that the API endpoints are updated to use the hostnames that are currently outlined in the API docs.