URL:
https://oracle-base.com/articles/19c/oracle-db-19c-installation-on-oracle-linux-8

Automatic Setup:
================
# dnf install -y oracle-database-preinstall-19c

It is probably worth doing a full update as well, but this is not strictly speaking necessary.
# yum update -y

Manual Setup:
=============
/etc/sysctl.conf:
fs.file-max = 6815744
kernel.sem = 250 32000 100 128
kernel.shmmni = 4096
kernel.shmall = 1073741824
kernel.shmmax = 4398046511104
kernel.panic_on_oops = 1
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
net.ipv4.conf.all.rp_filter = 2
net.ipv4.conf.default.rp_filter = 2
fs.aio-max-nr = 1048576
net.ipv4.ip_local_port_range = 9000 65500

sysctl -p

/etc/security/limits.d/oracle-database-preinstall-19c.conf
oracle   soft   nofile    1024
oracle   hard   nofile    65536
oracle   soft   nproc    16384
oracle   hard   nproc    16384
oracle   soft   stack    10240
oracle   hard   stack    32768
oracle   hard   memlock    134217728
oracle   soft   memlock    134217728


The following packages are listed as required. 
dnf install -y bc    
dnf install -y binutils
#dnf install -y compat-libcap1
dnf install -y compat-libstdc++-33
#dnf install -y dtrace-modules
#dnf install -y dtrace-modules-headers
#dnf install -y dtrace-modules-provider-headers
#dnf install -y dtrace-utils
dnf install -y elfutils-libelf
dnf install -y elfutils-libelf-devel
dnf install -y fontconfig-devel
dnf install -y glibc
dnf install -y glibc-devel
dnf install -y ksh
dnf install -y libaio
dnf install -y libaio-devel
#dnf install -y libdtrace-ctf-devel
dnf install -y libXrender
dnf install -y libXrender-devel
dnf install -y libX11
dnf install -y libXau
dnf install -y libXi
dnf install -y libXtst
dnf install -y libgcc
dnf install -y librdmacm-devel
dnf install -y libstdc++
dnf install -y libstdc++-devel
dnf install -y libxcb
dnf install -y make
dnf install -y net-tools # Clusterware
dnf install -y nfs-utils # ACFS
dnf install -y python # ACFS
dnf install -y python-configshell # ACFS
dnf install -y python-rtslib # ACFS
dnf install -y python-six # ACFS
dnf install -y targetcli # ACFS
dnf install -y smartmontools
dnf install -y sysstat

# Added by me.
dnf install -y unixODBC

# New for OL8
dnf install -y libnsl
dnf install -y libnsl.i686
dnf install -y libnsl2
dnf install -y libnsl2.i686

passwd oracle

/etc/selinux/config
SELINUX=permissive

If you have the Linux firewall enabled
# systemctl stop firewalld
# systemctl disable firewalld

Create the directories in which the Oracle software will be installed. <use linux7 >
Create the directories in which the Oracle software will be installed
mkdir -p  /u01/db/oracle/19.3.0/db_1
chmod -R 777 /u01/db/
chown -R oracle:oinstall /u01/db/
mkdir -p /u01/app/oracle
chown -R oracle:oinstall /u01/app/
chmod -R 777 /u01/app/


Log in as the “oracle” user and add the following lines at the end of the “/home/oracle/.bash_profile” file.

# Oracle Settings
export CV_ASSUME_DISTID=OEL8.1    # solve issue of graphic installer
 export TMP=/tmp
 export TMPDIR=$TMP
 export ORACLE_BASE=/u01/app/oracle
# export GRID_HOME=/u01/app/19c/grid
 export DB_HOME=/u01/crs/oracle/19.3.0/db_1
 export ORACLE_HOME=$DB_HOME
# export ORACLE_SID=TEST
 export ORACLE_TERM=xterm
 export BASE_PATH=/usr/sbin:$PATH
 export PATH=$ORACLE_HOME/bin:$BASE_PATH
 export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
 export CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib
alias grid='. /home/oracle/grid.env'
alias db='. /home/oracle/db.env'

export ORACLE_SID=TEST
 export ORACLE_HOME=/u01/db/oracle/19.3.0/db_1
 export PATH=$ORACLE_HOME/bin:$BASE_PATH
 export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
 export CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

Grid Home bash profile

Create a file called “/home/oracle/grid.env” with the following contents.

export ORACLE_SID=+ASM
 export ORACLE_HOME=/u01/crs/oracle/19.3.0/db_1
 export PATH=$ORACLE_HOME/bin:$BASE_PATH
 export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
 export CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

Oracle Home bash profile

Create a file called “/home/oracle/db.env” with the following contents.

export ORACLE_SID=TEST
 export ORACLE_HOME=/u01/db/oracle/19.3.0/db_1
 export PATH=$ORACLE_HOME/bin:$BASE_PATH
 export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
 export CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

===============
How to Resolve INS-08101 Unexpected Error: 
export CV_ASSUME_DISTID=OEL8.1

Oracle CC135:
oracle .bash_profile:
---------------------
# Oracle Settings
  
 export TMP=/tmp
 export TMPDIR=$TMP
 export ORACLE_BASE=/u01/app/oracle
 export ORACLE_TERM=xterm
 export BASE_PATH=/usr/sbin:$PATH
 export PATH=$ORACLE_HOME/bin:$BASE_PATH
 export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
 export CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib
 export CV_ASSUME_DISTID=OEL8.1    
 export ORACLE_SID=TEST
 export ORACLE_HOME=/u01/db/oracle/19.3.0/db_1
 export PATH=$ORACLE_HOME/bin:$BASE_PATH
 export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
 export CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib