After years of installing Grid Infrastructures, today I have got for the first time an error on something new:
$ /u01/app/grid/crs1840/gridSetup.sh -silent -responseFile /u01/app/grid/crs1840/inventory/response/CERNDB_Grid_Config.rsp ORACLE_HOME_NAME=crs1840 Launching Oracle Grid Infrastructure Setup Wizard... [FATAL] [INS-13013] Target environment does not meet some mandatory requirements. CAUSE: Some of the mandatory prerequisites are not met. See logs for details. /tmp/GridSetupActions2018-11-13_12-40-03PM/gridSetupActions2018-11-13_12-40-03PM.log ACTION: Identify the list of failed prerequisite checks from the log: /tmp/GridSetupActions2018-11-13_12-40-03PM/gridSetupActions2018-11-13_12-40-03PM.log. Then either from the log file or from installation manual find the appropriate configuration to meet the prerequisites and fix it manually.
Looking at the logs (which I do not have now as I removed them as part of the failed install cleanup 
), the error is generated by the cluster verification utility (CVU) on this check:
Verifying Port Availability for component "Oracle Remote Method Invocation (ORMI)"
The components verified by the CVU can be found inside $ORACLE_HOME/cv/cvdata/. In my case, precisely:
$ grep -i ORMI $ORACLE_HOME/cv/cvdata/18/crsinst_prereq.xml
<PORT NAME="Oracle Remote Method Invocation (ORMI)" VALUE="23791" PROTOCOL="TCP" NETWORK_TYPE="PUBLIC"/>
<PORT NAME="Oracle Remote Method Invocation (ORMI)" VALUE="23792" PROTOCOL="TCP" NETWORK_TYPE="PUBLIC"/>This check is critical, so the install fails.
In my case the port was used by mcollectived.
[root@server1 work]# netstat -anp | grep 23791 [root@server1 work]# netstat -anp | grep 23792 tcp 0 0 x.x.x.x:23792 x.x.x.x:61613 ESTABLISHED 2298/ruby [root@server1 work]# ps -eaf | grep 2298 root 2298 1 0 11:16 ? 00:00:02 /opt/puppetlabs/puppet/bin/ruby /opt/puppetlabs/puppet/bin/mcollectived --config=/etc/puppetlabs/mcollective/server.cfg --pidfile=/var/run/puppetlabs/mcollective.pid --daemonize root 47116 4114 0 12:50 pts/0 00:00:00 grep --color=auto 2298
The port has been taken dynamically, and previous runs of CVU did not encounter the problem.
A rare port conflict that might happen when configuring GI 
—
Ludo