[oracle@test tmp]$ /mnt/runInstaller silent -ignorePrereq \

-responseFile \
/home/oracle/db_install.rsp
Starting Oracle Universal Installer...

Checking Temp space: must be greater than 120 MB. Actual 25310 MB Passed
Checking swap space: must be greater than 150 MB. Actual 4031 MB Passed
Checking monitor: must be configured to display at least 256 colors

Could not execute auto check for display colors using command /usr/bin/xdpyinfo. Check if the DISPLAY variable is set. Failed <<<<

Some requirement checks failed. You must fulfill these requirements before

continuing with the installation,

Continue? (y/n) [n] y

Ignoring required pre-requisite failures. Continuing...
Preparing to launch Oracle Universal Installer from /tmp/OraInstall2018-12-07_11-30-02AM. Please wait ...
DISPLAY not set. Please set the DISPLAY and try again.
Depending on the Unix Shell, you can use one of the following commands as examples to set the DISPLAY environment variable:

• For csh: % setenv DISPLAY 192.168.1.128:0.0
• For sh, ksh and bash: $ DISPLAY=192.168.1.128:0.0; export DISPLAY
  Use the following command to see what shell is being used:
  echo $SHELL
  Use the following command to view the current DISPLAY environment variable setting:
  echo $DISPLAY
• Make sure that client users are authorized to connect to the X Server.
  To enable client users to access the X Server, open an xterm, dtterm or xconsole as the user that started the session and type the following command:
  % xhost +
  To test that the DISPLAY environment variable is set correctly, run a X11 based program that comes with the native operating system such as 'xclock':
  %
  If you are not able to run xclock successfully, please refer to your PC-X Server or OS vendor for further assistance.
  Typical path for xclock: /usr/X11R6/bin/xclock

解决方法： 加上-ignoreSysPrereqs；由于oracle默认不支持CentOS，安装时加参数-ignoreSysPrereqs 忽略系统检查提示
[oracle@test~]$ /mnt/runInstaller \

-ignoreSysPrereqs \
-silent -ignorePrereq \
-responseFile \
/home/oracle/db_install.rsp
Starting Oracle Universal Installer...

Checking Temp space: must be greater than 120 MB. Actual 24920 MB Passed
Checking swap space: must be greater than 150 MB. Actual 4031 MB Passed
Preparing to launch Oracle Universal Installer from /tmp/OraInstall2018-12-07_01-10-46PM. Please wait ...[oracle@test ~]$ [WARNING] [INS-32055] The Central Inventory is located in the Oracle base.
CAUSE: The Central Inventory is located in the Oracle base.
ACTION: Oracle recommends placing this Central Inventory in a location outside the Oracle base directory.
[WARNING] [INS-32055] The Central Inventory is located in the Oracle base.
CAUSE: The Central Inventory is located in the Oracle base.
ACTION: Oracle recommends placing this Central Inventory in a location outside the Oracle base directory.
You can find the log of this install session at:
/opt/oracle/oraInventory/logs/installActions2018-12-07_01-10-46PM.log