I have an OpenStack cloud and added the CentOS-7-x86_64-GenericCloud-1503 image and it boots just fine, but I do not know how to login. What is the root password? How can I set it? Is there some other account I need to use?
The default username for the CentOS 7 cloud image is
centos. There is no password; instead you log in with the ssh key you provided at instance creation. You can then sudo and do whatever you like.