I've noticed that on every cloudStack management server startup, the public RSA key gets overridden (vi ~/.ssh/id_rsa.pub). I'm running cloudStack on OSX 10.8.2. Not sure if it's a known issue, so raised a new bug against 4.2 (donno if it exists in 4.1 branch).
https://issues.apache.org/jira/browse/CLOUDSTACK-1560 -Alena.