Add services stuck at "Preparing to Deploy: 5 of 11 tasks completed" forever

[MEIerror]

I add services on ambari,everything works fine up to this point,after which it remains at "Preparing to Deploy: 5 of 11 tasks completed."forevery. and ambari-server.log no obvious errors.

I'm sure hosts iptables selinux and the time has been synced.because other services have been installed successful.
By the way,there were error in hosts and some nodes hostname,but it's all right now.

So is such a problem a database?