I have the following things are running on OracleVmBox. My host is window-10.

192.168.88.90   CentOs 7    Rancher     docker-version is 17.03.2
192.168.88.108  CentOs 7    Node-1      docker-version is 17.03.2
192.168.88.112  CentOs 7    Node-2      docker-version is 17.03.2
192.168.88.113  CentOs 7    Node-3      docker-version is 17.03.2

I already install Rancher sever on 192.168.88.90 and I create a new cluster.

And, I run the following commend in all node.

docker run -d --privileged --restart=unless-stopped --net=host -v /etc/kubernetes:/etc/kubernetes \ 
-v /var/run:/var/run rancher/rancher-agent:v2.1.5 --server https://192.168.88.90 \ 
--token vsfvjnbsggrkjd5vmnbmddn4q6jhsqtfhzj44wxb7cc92q87r9cjkc \
--ca-checksum 87d755c7c304dc3c2cdbca307aef4874ed3d17789da62826c0aa812bd10d3cf9 \ 
--etcd --controlplane --worker

The problems is, only first node(192.168.88.108) is register/add in cluster because of I run above commend in 192.168.88.108 at first and Node-2 and Node-3 and so on. Node-2 and Node-3 are not registed/add into the cluster.

Update