update doc

sbin/start_agent_master.sh

@@ -2,9 +2,10 @@
 
 docker service create \
 	--name yao-agent-master \
-	--network yao-net \
+	--hostname yao-agent-master \
 	--constraint node.role==manager \
-	--mode global \
+	--network yao-net \
+	--replicas 1 \
 	--detach=true \
 	--mount type=bind,source=/etc/localtime,target=/etc/localtime,readonly \
 	--mount type=bind,src=/var/run/docker.sock,dst=/var/run/docker.sock \