[FATAL] [INS-35423] The installer has detected that Oracle Clusterware is not running on local node.

When installing Oracle Database 19c on a RAC environment, a critical error may occur:

[FATAL] [INS-35423] The installer has detected that Oracle Clusterware is not running on local node.

Here’s a log fragment where this issue appears:

Possible Causes and Solutions for [INS-35423] Error

1. Oracle Clusterware (CRS) is not running

Description:
Clusterware is installed but not started.

Solution:
Check the CRS status:

$ crsctl check crs

If services are stopped, start them:

$ crsctl start crs

(Note: Requires root privileges!)

2. Incorrect /etc/hosts configuration

Description:
The Oracle installer might misinterpret the hostname if /etc/hosts is incorrectly configured.

Correct format should look like:

192.168.100.101 racnode1 racnode1.domain

Incorrect format:

192.168.100.101 racnode1.domain racnode1

Solution:

• Open the /etc/hosts file:

  sudo vi /etc/hosts

• Correct the order: first short hostname, then full domain name.

3. Using clufy tool to detect and fix errors

Description:
Oracle provides the clufy tool for cluster environment validation.

Usage:

$ cluvfy stage -post crsinst -n <list_of_nodes> -verbose

For example:

$ cluvfy stage -post crsinst -n node01-7,node02-7,node03-7 -verbose

Solution:

• Run clufy and analyze the results.

• Fix all detected issues (e.g., network issues, user errors, missing groups, ASM disks).

• After fixing, recheck the environment.