tikv, op-guide: refine TiKV Ansible deployment steps and update IPs (#…

…559)

* tikv, op-guide: refine TiKV Ansible deployment steps and update IPs

Via: #508, #531, ...

* op-guide, tikv: address comments

op-guide/ansible-deployment.md

@@ -26,15 +26,15 @@ You can use the TiDB-Ansible configuration file to set up the cluster topology a
 - [Clean up data of the TiDB cluster](ansible-operation.md#clean-up-cluster-data)
 - [Destroy the TiDB cluster](ansible-operation.md#destroy-a-cluster)
 
-## Prerequisites
+## Prepare
 
 Before you start, make sure you have:
 
 1. Several target machines that meet the following requirements:
 
     - 4 or more machines
 
-        A standard TiDB cluster contains 6 machines. You can use 4 machines for testing.
+        A standard TiDB cluster contains 6 machines. You can use 4 machines for testing. For more details, see [Software and Hardware Requirements](recommendation.md).
 
     - CentOS 7.3 (64 bit) or later, x86_64 architecture (AMD64)
     - Network between machines
@@ -171,14 +171,12 @@ Make sure you have logged in to the Control Machine using the `tidb` user accoun
     $ cd /home/tidb/tidb-ansible
     $ vi hosts.ini
     [servers]
-    192.168.0.2
-    192.168.0.3
-    192.168.0.4
-    192.168.0.5
-    192.168.0.6
-    192.168.0.7
-    192.168.0.8
-    192.168.0.10
+    172.16.10.1
+    172.16.10.2
+    172.16.10.3
+    172.16.10.4
+    172.16.10.5
+    172.16.10.6
 
     [all:vars]
     username = tidb