Using Ecualyptus slaves, it can take a while before the DNS name is populated with the correct IP is referenced by the name. Until then, euca-0-0-0-0.eucalyptus.eucadomain... is presented.

Needless to say, if the ec2 plugin tries to connect to that name, it fails.

The mitigation would seem to be to allow a wait before connect option, or a retry option which re-checks dns on retry.

I edited the plugin myself to add a dumb fixed 60s delay and that did fix the issue, however this should be fixed properly.

Stack trace follows.

Connecting to euca-0-0-0-0.eucalyptus.eucadomain.sc.local on port 22.
Connected via SSH.
bootstrap()
Getting keypair...
Using key: jenkins
cc:05:1a:f4:95:e0:0d:99:b9:ea:56:fd:6c:90:a1:d0:85:8d:74:5e
----BEGIN RSA PRIVATE KEY----
MIIEpAIBAAKCAQEAn/addoIs+dTHJlhb6D+mex0m/hdXbQz5UWBDIKnU5g2cPWFW
L4n0HaoJ8nHMSviDmzFfZ+Mdutn+aEzSz/lvmHK1VS4tJ+W5adFc6CcohFU2u6w
Authenticating as sc
Authentication failed. Trying again...
Authenticating as sc
Authentication failed. Trying again...
Authenticating as sc
Authentication failed. Trying again...
Authenticating as sc
Authentication failed. Trying again...
Authenticating as sc
Authentication failed. Trying again...
Authenticating as sc
ERROR: Publickey authentication failed.
java.io.IOException: Publickey authentication failed.
at com.trilead.ssh2.auth.AuthenticationManager.authenticatePublicKey(AuthenticationManager.java:264)
at com.trilead.ssh2.Connection.authenticateWithPublicKey(Connection.java:445)
at hudson.plugins.ec2.ssh.EC2UnixLauncher.bootstrap(EC2UnixLauncher.java:187)
at hudson.plugins.ec2.ssh.EC2UnixLauncher.launch(EC2UnixLauncher.java:77)
at hudson.plugins.ec2.EC2ComputerLauncher.launch(EC2ComputerLauncher.java:80)
at hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:230)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
Caused by: java.io.IOException: The connection is closed.
at com.trilead.ssh2.auth.AuthenticationManager.deQueue(AuthenticationManager.java:79)
at com.trilead.ssh2.auth.AuthenticationManager.getNextMessage(AuthenticationManager.java:102)
at com.trilead.ssh2.auth.AuthenticationManager.authenticatePublicKey(AuthenticationManager.java:239)
... 10 more
Caused by: java.io.IOException: Peer sent DISCONNECT message (reason code 2): Too many authentication failures for spacecurve
at com.trilead.ssh2.transport.TransportManager.receiveLoop(TransportManager.java:750)
at com.trilead.ssh2.transport.TransportManager$1.run(TransportManager.java:475)
... 1 more