1. To begin, make sure that all the packages currently installed on your RHEL/CentOS 7 system are updated to their latest versions.
# yum update -y

2. Next, installed all the required dependencies for the RDBMS, along with the zip and unzip packages.
# yum install -y binutils.x86_64 compat-libcap1.x86_64 gcc.x86_64 gcc-c++.x86_64 glibc.i686 glibc.x86_64 glibc-devel.i686 glibc-devel.x86_64 ksh compat-libstdc++-33 libaio.i686 libaio.x86_64 libaio-devel.i686 libaio-devel.x86_64 libgcc.i686 libgcc.x86_64 libstdc++.i686 libstdc++.x86_64 libstdc++-devel.i686 libstdc++-devel.x86_64 libXi.i686 libXi.x86_64 libXtst.i686 libXtst.x86_64 make.x86_64 sysstat.x86_64 zip unzip


3. Create the user account and groups for Oracle.
# groupadd oinstall
# groupadd dba
# useradd -g oinstall -G dba oracle
# passwd oracle

How can I install X Windows on CentOS 7?
sudo yum groupinstall "GNOME Desktop"  # install lots of stuff 
sudo yum groupinstall "Graphical Administration Tools"  
... 
sudo systemctl enable graphical.target 
sudo systemctl start graphical.target 

<gui should start>
sudo systemctl set-default graphical.target 
sudo systemctl get-default 
graphical.target 
sudo systemctl reboot 

4. Add the following kernel parameters to /etc/sysctl.conf file.
fs.aio-max-nr = 1048576
fs.file-max = 6815744
kernel.shmall = 2097152
kernel.shmmax = 8329226240
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048586


and apply them:
# sysctl -p
# sysctl -a


5. Set the limits for oracle in /etc/security/limits.conf file.
oracle soft nproc 2047
oracle hard nproc 16384
oracle soft nofile 1024
oracle hard nofile 65536


6. Before proceeding, create other directories that will be used during the actual installation, and assign the necessary permissions.
# mkdir /u01 /u02
# chown -R oracle:oinstall /u01 /u02
# chmod -R 775 /u01 /u02
# chmod g+s /u01 /u02


7. Open a GUI session in the RHEL/CentOS 7 server and launch the installation script.
# ./runInstaller