Verify undercloud fits the CPU core requirements.
Make sure that the undercloud has enough CPU cores. https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/7/html/Director_Installation_and_Usage/sect-Undercloud_Requirements.html
Verify undercloud fits the disk space requirements.
Make sure that the root partition on the undercloud node is large enough. We first check for an explicit /var mount point since that’s where we store logs and images and if it doesn’t exist, we fall back to /. http://tripleo.org/environments/environments.html#id5
Verify the undercloud fits the RAM requirements.
Verify that the undercloud has enough RAM. https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/7/html/Director_Installation_and_Usage/sect-Undercloud_Requirements.html