UPGRADE 19c 2 node RAC cluster from 19.3 to 19.8 with July 2020 RU

Environment: 19.3 2 node RAC cluster.

Latest OPatch:                      : p6880880_190000_Linux-x86-64.zip  -- to get OPatch Version: 12.2.0.1.23

GI Release Update (July 2020) : p31305339_190000_Linux-x86-64.zip

Database Release Update (July 2020) : p31281355_190000_Linux-x86-64.zip

RU: Release Updates

followed exactly what is given in READ-ME files however below errors are seen.

  Following active executables are used by opatch process :

[Dec 15, 2020 2:44:55 AM] [INFO]    Prerequisite check "CheckActiveFilesAndExecutables" failed.

                                    The details are:

                                    Following active executables are not used by opatch process :

                                    //...//u01/app/19.3.0/grid/lib/libclntsh.so.19.1

                                    //...//u01/app/19.3.0/grid/lib/libasmclntsh19.so

                                    Following active executables are used by opatch process :

[Dec 15, 2020 2:44:55 AM] [SEVERE]  OUI-67073:UtilSession failed: Prerequisite check "CheckActiveFilesAndExecutables" failed.

[Dec 15, 2020 2:44:55 AM] [INFO]    Finishing UtilSession at Tue Dec 15 02:44:55 PST 2020

[Dec 15, 2020 2:44:55 AM] [INFO]    Log file location: //...//u01/app/19.3.0/grid/cfgtoollogs/opatchauto/core/opatch/opatch2020-12-15_02-41-24AM_1.log

bash-4.2$ /sbin/fuser //...//u01/app/19.3.0/grid/lib/libclntsh.so.19.1; /sbin/fuser //...//u01/app/19.3.0/grid/lib/libasmclntsh19.so

//...//u01/app/19.3.0/grid/lib/libclntsh.so.19.1: 13192m 13214m 13216m 13245m 13298m 13402m

//...//u01/app/19.3.0/grid/lib/libasmclntsh19.so: 13192m 13214m 13216m 13245m 13298m 13402m

bash-4.2$ ps -elf |egrep '13192 | 13214 | 13216 | 13245 | 13298 | 13402' |grep -iv grep                                                 4 S oracle   13192     1  0  80   0 - 421363 futex_ 01:28 ?       00:01:14 //...//u01/app/19.3.0/grid/bin/oraagent.bin

0 S oracle   13214     1  0  80   0 - 92685 poll_s 01:28 ?        00:00:43 //...//u01/app/19.3.0/grid/bin/mdnsd.bin

0 S oracle   13216     1  0  80   0 - 217186 poll_s 01:28 ?       00:01:39 //...//u01/app/19.3.0/grid/bin/evmd.bin

0 S oracle   13245     1  0  80   0 - 264129 hrtime 01:28 ?       00:00:48 //...//u01/app/19.3.0/grid/bin/gpnpd.bin

0 S oracle   13298 13216  0  80   0 - 111523 poll_s 01:28 ?       00:00:42 //...//u01/app/19.3.0/grid/bin/evmlogger.bin -o //...//u01/app/19.3.0/grid/log/[HOSTNAME]/evmd/evmlogger.info -l //...//u01/app/19.3.0/grid/log/[HOSTNAME]/evmd/evmlogger.log

4 S oracle   13402     1  0 -40   - - 674556 futex_ 01:28 ?       00:01:33 //...//u01/app/19.3.0/grid/bin/ocssd.bin

bash-4.2$

Any attempt to kill anyone of the above processes linked to said two lib* executable resulted two nodes get rebooted automatically even if we ran on single node... 

In my case: I followed 

Prerequisite check CheckActiveFilesAndExecutables failed on executable libclntsh.so.12.1 with opatch rollback (Doc ID 2391109.1)

and ensured all the cluster resources are relocated to another node on which patch is not being applied. 

thereafter I was able apply RU patch, first on Grid, and oracle home. on each of the nodes one after another.