An issue arrises when a domain's A record resolution is attempted before Route53 publishes the clusters A record, and the NXDOMAIN response is cached in the NCACHE (RFC2308). The cached failure response makes resolution impossible until the negative caching TTL expires. These TTLs are typically large enough to disrupt the installation experience. The current workaround is to ensure your TTLs are set to a low interval, or to wait for them to expire, then proceed with the installation.
When copying your license and pull-secret from account.coreos.com, be sure to choose the correct format. The license format should be "Raw Format", the pull-secret should be in the "dockercfg" format.
Tectonic Installer may fail to download
assets.zip file during the Install due to a known issue in Safari/Webkit. OSX users are advised to use Firefox or Chrome to use Tectonic Installer on OSX machines.