check that we haven't already added host to cluster
check that we haven't already added host to cluster
MonsantoCo/etcd-aws-cluster,cnry/etcd-aws-cluster,PokaInc/etcd-aws-cluster,FitnessKeeper/etcd-aws-cluster,statik/etcd-aws-cluster,Katlean/etcd-aws-cluster,optimizely/etcd-aws-cluster,coreos/etcd-aws-cluster,xueshanf/etcd-aws-cluster,ocadotechnology/etcd-dynamic-cluster