After installing Centos 7, I noticed that DNS lookups for addresses saved in /etc/hosts take long time, here is example:time curl -X get http://localhostreal    0m0.159suser    0m0.004ssys     0m0.005sbuttime curl -X get http://127.0.0.1real    0m0.005suser    0m0.001ssys     0m0.003sIt takes ~ 0.15 secs to resolve localhost by each request.I make the same tests on another server in the same network with Centos 6.5 but localhost is as fast as 127.0.0.1
Centos 7 Slow Resolve
centos;dns