How to remove Oracle Grid Infrastructure, CRS and Oracle Restart.

As root user perform the following steps.

Deconfigure the CRS across the all nodes of the cluster

/u01/app/11.2.4/grid/crs/install/rootcrs.pl -deconfig  -verbose -force

In last node

/u01/app/11.2.4/grid/crs/install/rootcrs.pl -deconfig  -lastnode -force

Deconfigure the Oracle Restart SIHA and ASM

/u01/app/11.2.4/grid/crs/install/roothas.pl -deconfig -verbose -force

Modify /etc/inittab: (CRS and Oracle Restart)

vi /etc/inittab

#h1:35:respawn:/etc/init.d/init.ohasd run >/dev/null 2>&1 </dev/null
init q

Clean up files

rm -f /etc/init.d/init.ohasd
rm -f /etc/inittab.crs
rm -rf /etc/oracle
rm -f /usr/tmp/.oracle/*
rm -f /tmp/.oracle/*
rm -f /var/tmp/.oracle/*
[Be carefull it will remove oratab entries for all database running on this server]
rm -f /etc/oratab
rm -rf /var/opt/oracle

rm -rf /u01/app/* 

Log

[root@sbldcdb01 install]# ./rootcrs.pl -deconfig  -lastnode -force
Using configuration parameter file: ./crsconfig_params
CRS resources for listeners are still configured
Network exists: 1/172.31.36.0/255.255.255.128/, type static
VIP exists: /sbldcdb01-vip/172.31.36.26/172.31.36.0/255.255.255.128/, hosting node sbldcdb01
VIP exists: /sbldcdb02-vip/172.31.36.27/172.31.36.0/255.255.255.128/, hosting node sbldcdb02
GSD exists
ONS exists: Local port 6100, remote port 6200, EM port 2016
CRS-2673: Attempting to stop 'ora.registry.acfs' on 'sbldcdb01'
CRS-2677: Stop of 'ora.registry.acfs' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.crsd' on 'sbldcdb01'
CRS-2790: Starting shutdown of Cluster Ready Services-managed resources on 'sbldcdb01'
CRS-2673: Attempting to stop 'ora.oc4j' on 'sbldcdb01'
CRS-2673: Attempting to stop 'ora.OCR.dg' on 'sbldcdb01'
CRS-2677: Stop of 'ora.oc4j' on 'sbldcdb01' succeeded
CRS-2677: Stop of 'ora.OCR.dg' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.asm' on 'sbldcdb01'
CRS-2677: Stop of 'ora.asm' on 'sbldcdb01' succeeded
CRS-2792: Shutdown of Cluster Ready Services-managed resources on 'sbldcdb01' has completed
CRS-2677: Stop of 'ora.crsd' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.ctssd' on 'sbldcdb01'
CRS-2673: Attempting to stop 'ora.evmd' on 'sbldcdb01'
CRS-2673: Attempting to stop 'ora.asm' on 'sbldcdb01'
CRS-2677: Stop of 'ora.evmd' on 'sbldcdb01' succeeded
CRS-2677: Stop of 'ora.ctssd' on 'sbldcdb01' succeeded
CRS-2677: Stop of 'ora.asm' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.cluster_interconnect.haip' on 'sbldcdb01'
CRS-2677: Stop of 'ora.cluster_interconnect.haip' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.cssd' on 'sbldcdb01'
CRS-2677: Stop of 'ora.cssd' on 'sbldcdb01' succeeded
CRS-2672: Attempting to start 'ora.cssdmonitor' on 'sbldcdb01'
CRS-2676: Start of 'ora.cssdmonitor' on 'sbldcdb01' succeeded
CRS-2672: Attempting to start 'ora.cssd' on 'sbldcdb01'
CRS-2672: Attempting to start 'ora.diskmon' on 'sbldcdb01'
CRS-2676: Start of 'ora.diskmon' on 'sbldcdb01' succeeded
CRS-2676: Start of 'ora.cssd' on 'sbldcdb01' succeeded
CRS-4611: Successful deletion of voting disk +OCR.
ASM de-configuration trace file location: /tmp/asmcadc_clean2016-05-02_06-50-58-PM.log
ASM Clean Configuration START
ASM Clean Configuration END

ASM with SID +ASM1 deleted successfully. Check /tmp/asmcadc_clean2016-05-02_06-50-58-PM.log for details.

CRS-2791: Starting shutdown of Oracle High Availability Services-managed resources on 'sbldcdb01'
CRS-2673: Attempting to stop 'ora.ctssd' on 'sbldcdb01'
CRS-2673: Attempting to stop 'ora.cluster_interconnect.haip' on 'sbldcdb01'
CRS-2673: Attempting to stop 'ora.mdnsd' on 'sbldcdb01'
CRS-2677: Stop of 'ora.cluster_interconnect.haip' on 'sbldcdb01' succeeded
CRS-2677: Stop of 'ora.mdnsd' on 'sbldcdb01' succeeded
CRS-2677: Stop of 'ora.ctssd' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.cssd' on 'sbldcdb01'
CRS-2677: Stop of 'ora.cssd' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.crf' on 'sbldcdb01'
CRS-2677: Stop of 'ora.crf' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.gipcd' on 'sbldcdb01'
CRS-2677: Stop of 'ora.gipcd' on 'sbldcdb01' succeeded
CRS-2673: Attempting to stop 'ora.gpnpd' on 'sbldcdb01'
CRS-2677: Stop of 'ora.gpnpd' on 'sbldcdb01' succeeded
CRS-2793: Shutdown of Oracle High Availability Services-managed resources on 'sbldcdb01' has completed
CRS-4133: Oracle High Availability Services has been stopped.
Removing Trace File Analyzer
Successfully deconfigured Oracle clusterware stack on this node
[root@sbldcdb01 install]#
[root@sbldcdb01 install]# ./roothas.pl -deconfig -verbose -force 
Using configuration parameter file: ./crsconfig_params
CRS-4047: No Oracle Clusterware components configured.
CRS-4000: Command Stop failed, or completed with errors.
CRS-4047: No Oracle Clusterware components configured.
CRS-4000: Command Delete failed, or completed with errors.
CRS-4047: No Oracle Clusterware components configured.
CRS-4000: Command Stop failed, or completed with errors.
You must kill ohasd processes or reboot the system to properly
cleanup the processes started by Oracle clusterware
ACFS-9313: No ADVM/ACFS installation detected.
Either /etc/oracle/olr.loc does not exist or is not readable
Make sure the file exists and it has read and execute access
Failure in execution (rc=-1, 256, No such file or directory) for command /etc/init.d/ohasd deinstall
Successfully deconfigured Oracle Restart stack
[root@sbldcdb01 install]#
[root@sbldcdb01 install]# rm -f /etc/init.d/init.ohasd
[root@sbldcdb01 install]# rm -f /etc/inittab.crs
[root@sbldcdb01 install]# rm -rf /etc/oracle
[root@sbldcdb01 install]# rm -f /usr/tmp/.oracle/*
[root@sbldcdb01 install]# rm -f /tmp/.oracle/*
[root@sbldcdb01 install]# rm -f /var/tmp/.oracle/*
[root@sbldcdb01 install]# rm -f /etc/oratab
[root@sbldcdb01 install]# rm -rf /var/opt/oracle