$ cap deploy
    triggering start callbacks for `deploy'
  * executing `multistage:ensure'
*** Defaulting to `qa'
  * executing `qa'
  * executing `deploy'
  * executing `deploy:update'
 ** transaction: start
  * executing `deploy:update_code'
    executing locally: "git ls-remote git@github.com:ORG_NAME/APP_NAME.git HEAD"
  * executing "git clone -q git@github.com:ORG_NAME/APP_NAME.git /var/www/APP_NAME/releases/20101228163613 && cd /var/www/APP_NAME/releases/20101228163613 && git checkout -q -b deploy fcdf490266c1df26da8495c059114be2f3bae29f && git submodule -q init && git submodule -q sync && git submodule -q update && (echo fcdf490266c1df26da8495c059114be2f3bae29f > /var/www/APP_NAME/releases/20101228163613/REVISION)"
    servers: ["qa.DEPLOY_HOST.com"]
    [qa.DEPLOY_HOST.com] executing command
 ** [qa.DEPLOY_HOST.com :: out] Permission denied (publickey).
 ** fatal: The remote end hung up unexpectedly
    command finished
*** [deploy:update_code] rolling back
  * executing "rm -rf /var/www/APP_NAME/releases/20101228163613; true"
    servers: ["qa.DEPLOY_HOST.com"]
    [qa.DEPLOY_HOST.com] executing command
    command finished
failed: "sh -c 'git clone -q git@github.com:ORG_NAME/APP_NAME.git /var/www/APP_NAME/releases/20101228163613 && cd /var/www/APP_NAME/releases/20101228163613 && git checkout -q -b deploy fcdf490266c1df26da8495c059114be2f3bae29f && git submodule -q init && git submodule -q sync && git submodule -q update && (echo fcdf490266c1df26da8495c059114be2f3bae29f > /var/www/APP_NAME/releases/20101228163613/REVISION)'" on qa.DEPLOY_HOST.com