诊断：RHEL7安装11.2RAC时root.sh错误ohasd failed to start

RHEL 7.5中安装11gRAC时，在grid infrastructure的root.sh执行时，报错：

# /oracle/product/11g/grid/root.sh
...
Adding Clusterware entries to inittab
ohasd failed to start
Failed to start the Clusterware. Last 20 lines of the alert log follow:
2019-01-04 17:02:36.004:
[client(25743)]CRS-2101:The OLR was formatted using version 3.

这是由于RHEL 7改变了init的管理方式，出现了兼容性上的问题。官方给出了补丁18370031，在PSU 28429134也有包含,选择一个就好。

具体的处理方式为：
1、首先deinstall掉grid

$ORACLE_HOME/deinstall/deinstall

按照提示进行

2、按照常规步骤进行安装

3、在弹出root执行脚本时注意，先执行orainstRoot.sh，暂时先暂停

4、解压OPatch和补丁包

5、创建opatch 的ocmrf，但选择不启用

$ $ORACLE_HOME/OPatch/ocm/bin/emocmrsp -no_banner -output /oracle/ocm.rsp
Provide your email address to be informed of security issues, install and
initiate Oracle Configuration Manager. Easier for you if you use your My
Oracle Support Email address/User Name.
Visit http://www.oracle.com/support/policies.html for details.
Email address/User Name:    <----直接回车

You have not provided an email address for notification of security issues.
Do you wish to remain uninformed of security issues ([Y]es, [N]o) [N]: Y
The OCM configuration response file (/oracle/ocm.rsp) was successfully created.

6、打补丁18370031

$ /oracle/product/11g/grid/OPatch/opatch napply -oh /oracle/product/11g/grid -local /home/grid/ -ocmrf /oracle/ocm.rsp
Oracle Interim Patch Installer version 11.2.0.3.
Copyright (c) , Oracle Corporation. All rights reserved.

...

OPatch succeeded.

7、再执行root.sh

# /oracle/product/11g/grid/root.sh
...
Adding Clusterware entries to oracle-ohasd.service
CRS-: Attempting to start 'ora.mdnsd' on 'rac01'
CRS-: Start of 'ora.mdnsd' on 'rac01' succeeded
CRS-: Attempting to start 'ora.gpnpd' on 'rac01'
CRS-: Start of 'ora.gpnpd' on 'rac01' succeeded
CRS-: Attempting to start 'ora.cssdmonitor' on 'rac01'
CRS-: Attempting to start 'ora.gipcd' on 'rac01'
CRS-: Start of 'ora.cssdmonitor' on 'rac01' succeeded
CRS-: Start of 'ora.gipcd' on 'rac01' succeeded
CRS-: Attempting to start 'ora.cssd' on 'rac01'
CRS-: Attempting to start 'ora.diskmon' on 'rac01'
CRS-: Start of 'ora.diskmon' on 'rac01' succeeded
CRS-: Start of 'ora.cssd' on 'rac01' succeeded

ASM created and started successfully.

Disk Group GRID created successfully.

...
Configure Oracle Grid Infrastructure for a Cluster ... succeeded