Release tag 2.8 reworked the kwargs based implementation of the ec2 driver, introducing this error where the literal string 'ex_userdata' was passed during create_node intead of the actual ex_userdata kwarg.
@@ -1970,7 +1970,7 @@ class BaseEC2NodeDriver(NodeDriver):
params['KeyName'] = ex_keyname
if ex_userdata:
- params['UserData'] = base64.b64encode(b('ex_userdata'))\
+ params['UserData'] = base64.b64encode(b(ex_userdata))\
.decode('utf-8')
if ex_clienttoken:
