I think I use the right key.
but got error message below.
[2014-08-21T02:34:43+00:00] ERROR: Running exception handlers
[2014-08-21T02:34:43+00:00] ERROR: Exception handlers complete
[2014-08-21T02:34:43+00:00] FATAL: Stacktrace dumped to /var/lib/aws/opsworks/cache.stage2/chef-stacktrace.out
[2014-08-21T02:34:43+00:00] ERROR: deploy[/srv/www/rock] (deploy::rails line 65) had an error: Mixlib::ShellOut::ShellCommandFailed: Expected process to exit with [0], but received '128'
---- Begin output of git ls-remote "git@bitbucket.org:rock/rock.git" testmerge* ----
STDOUT:
STDERR: Warning: Permanently added 'bitbucket.org,131.103.20.167' (RSA) to the list of known hosts.
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
---- End output of git ls-remote "git@bitbucket.org:rock/rock.git" testmerge* ----
Ran git ls-remote "git@bitbucket.org:rock/rock.git" testmerge* returned 128
[2014-08-21T02:34:43+00:00] FATAL: Chef::Exceptions::ChildConvergeError: Chef run process exited unsuccessfully (exit code 1)

I submit two kinds of ssh key format below, and it failed both.

----BEGIN RSA PRIVATE KEY----
ssh-rsa
XXX
Alexis@alexisdembp
----END RSA PRIVATE KEY----

Or

----BEGIN RSA PRIVATE KEY----
XXX
----END RSA PRIVATE KEY----