Follow the Steps below to enable auto startup of DB instance , Listener and PDB's

1. Create dbora file as below with ORACLE_HOME

[root@oraclesrv ~]# cat /etc/init.d/dbora
#! /bin/sh -x
#
# chkconfig: 2345 80 05
# description: start and stop Oracle Database Enterprise Edition on Oracle Linux 5 and 6
#
# In /etc/oratab, change the autostart field from N to Y for any
# databases that you want autostarted.
#
# Create this file as /etc/init.d/dbora and execute:
# chmod 750 /etc/init.d/dbora
# chkconfig --add dbora
# chkconfig dbora on
# Note: Change the value of ORACLE_HOME to specify the correct Oracle home
# directory for your installation.
# ORACLE_HOME=/u01/app/oracle/product/11.1.0/db_1
ORACLE_HOME=/u01/app/oracle/db1
#
# Note: Change the value of ORACLE to the login name of the oracle owner
ORACLE=oracle
PATH=${PATH}:$ORACLE_HOME/bin
HOST=`hostname`
PLATFORM=`uname`
export ORACLE_HOME PATH
case $1 in
'status')
echo -n $"Oracle Process: "
su $ORACLE -c "ps -ef | grep pmon | grep -v grep; ps -ef | grep -i listener | grep -v grep;" &
;;
'start')
echo -n $"Starting Oracle: "
su $ORACLE -c "$ORACLE_HOME/bin/dbstart $ORACLE_HOME" &
;;
'stop')
echo -n $"Shutting down Oracle: "
su $ORACLE -c "$ORACLE_HOME/bin/dbshut $ORACLE_HOME" &
;;
'restart')
echo -n $"Shutting down Oracle: "
su $ORACLE -c "$ORACLE_HOME/bin/dbshut $ORACLE_HOME" &
sleep 5
echo -n $"Starting Oracle: "
su $ORACLE -c "$ORACLE_HOME/bin/dbstart $ORACLE_HOME" &
;;
*)
echo "usage: $0 {start|stop|restart}"
exit
;;
esac
exit

In this article will perform step by step installation of Oracle 19c single instance database on Oracle Linux 7 operating system hosted on virtual box.

Prior to proceeding with the steps , do refer following link to setup a LAB environment which includes Installation of Oracle Virtual Box on windows and operating system Oracle Linux 7 setup.

Step by Step Virtual Linux LAB Setup

Oracle Linux Installation on Virtual Box

Oracle 19c installation steps will include ..

1. Setting up internet network connection from virtual machine

2. Installation of prerequisite oracle 19c

3. Configuring & downloading Oracle 19c home setup

4. Performing oracle 19c installation

5. De-installation / Setup Cleanup

Lets begin ..

1. Setting up internet network connection from virtual machine

Internet connectivity within virtual host is must to install pre-requisite rpm for oracle 19c database installation as well few ad-hoc dependent rpm's using yum

Verify if NAT is selected for Adpater 1..

Add port forwarding for connecting the virtual machine from outside terminal ..

In windows host make sure wireless network ethernet adapter internet sharing is enabled from below path

Control Panel\Network and Internet\Network Connections

Make sure ONBOOT=yes in /etc/sysconfig/network-scripts

Either reboot the virtual machine or use ifdown & ifup to reflect appropriate nameserver entry in resolv.conf post host entry addition

ifconfig -a output should look like below ..

2. Installation of prerequisite oracle 19c

Downlod & install the oracle 19c database preinstall rpm which will create the user, groups and install necessary kernal packages/rpm's required as a prerequisites ..

[root@oraclesrv ~]# yum -y install oracle-database-preinstall-19c
Loaded plugins: langpacks, ulninfo
Resolving Dependencies
--> Running transaction check
---> Package oracle-database-preinstall-19c.

3. Configuring & downloading Oracle 19c home setup

Create installation directory for oracle home ..

db1
[oracle@oraclesrv db1]$ ls -lrt
total 2987996
-rwxr-x--- 1 oracle oinstall 3059705302 Nov 4 12:27 LINUX.X64_193000_db_home.zip
[oracle@oraclesrv db1]$ unzip LINUX.X64_193000_db_home.zip

Verify if xclock is able to launch .. setup appropriate DISPLAY parameter & copy .Xauthority file if required

[oracle@oraclesrv db1]$ xclock
bash: xclock: command not found...
Similar command is: 'clock'
[oracle@oraclesrv db1]$ exit
logout
[root@oraclesrv ~]# yum install xclock
Loaded plugins: langpacks, ulninfo
ol7_UEKR5   | 2.5 kB 00:00:00
ol7_latest | 2.7 kB 00:00:00
(1/3):ol7_latest/x86_64/group | 660 kB 00:00:00
(2/3):ol7_latest/x86_64/updateinfo | 3.1 MB 00:00:01
(3/3):ol7_latest/x86_64/primary_db | 30 MB 00:00:04
Resolving Dependencies
--> Running transaction check
---> Package xorg-x11-apps.x86_64 0:7.7-7.el7 will be installed
--> Processing Dependency: libXaw.so.7()(64bit) for package: xorg-x11-apps-7.7-7.el7.x86_64
--> Running transaction check
---> Package libXaw.x86_64 0:1.0.13-4.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

=====================================================================
Package Arch   Version   Repository Size
=====================================================================
Installing:
xorg-x11-apps   x86_64   7.7-7.el7   ol7_latest 307 k

Installing for dependencies:
libXaw x86_64    1.0.13-4.el7 ol7_latest 191 k

Transaction Summary
=====================================================================
Install 1 Package (+1 Dependent package)

Total download size: 498 k
Installed size: 1.2 M
Is this ok [y/d/N]: y
Downloading packages:
(1/2): libXaw-1.0.13-4.el7.x86_64.rpm  | 191 kB 00:00:00
(2/2): xorg-x11-apps-7.7-7.el7.x86_64.rpm   | 307 kB 00:00:00
--------------------------------------------------------------------
Total   551 kB/s | 498 kB 00:00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : libXaw-1.0.13-4.el7.x86_64   1/2
Installing : xorg-x11-apps-7.7-7.el7.x86_64   2/2

Verifying : libXaw-1.0.13-4.el7.x86_64 1/2
Verifying : xorg-x11-apps-7.7-7.el7.x86_64 2/2

Installed:
xorg-x11-apps.x86_64 0:7.7-7.el7

Dependency Installed:
libXaw.x86_64 0:1.0.13-4.el7

Complete!

4. Performing oracle 19c installation

Create separate disks as /u01 & /data . also add swap space as their should not be any exception to be ignored using this link

[oracle@oraclesrv /]$ cd /u01/app/oracle/db1
[oracle@oraclesrv db1]$ ./runInstaller

As a new feature in oracle 19c root password to be supplied to avoid manual execution of post installation scripts

fix this swap issue following these steps

http://www.moreajays.com/2020/11/creating-new-swap-and-data-partition.html

Setup up bash profile for environment variables ..

[oracle@oraclesrv ~]$ cat .bash_profile
# .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi

# User specific environment and startup programs
ORACLE_HOME=/u01/app/oracle/db1
export ORACLE_HOME
ORACLE_SID=LEARN
export ORACLE_SID
PATH=$PATH:$HOME/.local/bin:$HOME/bin:$ORACLE_HOME/bin
export PATH
[oracle@oraclesrv ~]$
[oracle@oraclesrv ~]$ . ./.bash_profile

Try accessing EM express https://<servername>:5500/em

few commands on pdb to play ..

5. De-installation / Setup Cleanup

[oracle@oraclesrv /]$ cd /u01/app/oracle/db1

[oracle@oraclesrv db1]$ cd deinstall/

[oracle@oraclesrv deinstall]$ ls -lrt
total 172
-rw-r----- 1 oracle oinstall   401 Feb 10 2012 readme.txt
-rwxr-x--- 1 oracle oinstall 33333 Jan 7 2015 sshUserSetup.sh
-rw-r----- 1 oracle oinstall 8479 Sep 19 2017 deinstall.xml
-rwxr-x--- 1 oracle oinstall 33171 Apr 17 2019 deinstall.pl
-rwxr-x--- 1 oracle oinstall 14927 Apr 17 2019 bootstrap.pl
-rw-r----- 1 oracle oinstall 55480 Apr 17 2019 bootstrap_files.lst
drwxr-xr-x 2 oracle oinstall    32 Apr 17 2019 response
drwxr-xr-x 2 oracle oinstall    33 Apr 17 2019 utl
drwxr-xr-x 2 oracle oinstall   102 Apr 17 2019 jlib
-rwxr-x--- 1 oracle oinstall 11223 Nov 4 13:24 deinstall

[oracle@oraclesrv deinstall]$ ./deinstall
Checking for required files and bootstrapping ...
Please wait ...
Location of logs /tmp/deinstall2020-11-04_02-45-53PM/logs/

############ ORACLE DECONFIG TOOL START ############
######################### DECONFIG CHECK OPERATION START #########################
## [START] Install check configuration ##

Checking for existence of the Oracle home location /u01/app/oracle/db1
Oracle Home type selected for deinstall is: Oracle Single Instance Database
Oracle Base selected for deinstall is: /u01/app/oracle
Checking for existence of central inventory location /u01/app/oraInventory

## [END] Install check configuration ##

Network Configuration check config START
Network de-configuration trace file location: /tmp/deinstall2020-11-04_02-45-53PM/logs/netdc_check2020-11-04_02-47-59PM.log

Specify all Single Instance listeners that are to be de-configured. Enter .(dot) to deselect all. [LISTENER]:
Network Configuration check config END

Database Check Configuration START
Database de-configuration trace file location: /tmp/deinstall2020-11-04_02-45-53PM/logs/databasedc_check2020-11-04_02-47-59PM.log
Use comma as separator when specifying list of values as input
Specify the list of database names that are configured in this Oracle home [LEARN]:

###### For Database 'LEARN' ######

Specify the type of this database (1.Single Instance Database|2.Oracle Restart Enabled Database) [1]:
Specify the diagnostic destination location of the database [/u01/app/oracle/diag/rdbms/learn]:
Specify the storage type used by the Database ASM|FS []: FS

Specify the list of directories if any database files exist on a shared file system. If 'LEARN' subdirectory is found, then it will be deleted. Otherwise, the specified directory will be deleted. Alternatively, you can specify list of database files with full path [ ]:

Specify the fast recovery area location, if it is configured on the file system. If 'LEARN' subdirectory is found, then it will be deleted. []:

Specify the database spfile location [ ]:

Specify if database Archive Mode is Enabled. y/n [n]:
Database Check Configuration END

######################### DECONFIG CHECK OPERATION END #########################

####################### DECONFIG CHECK OPERATION SUMMARY #######################
Oracle Home selected for deinstall is: /u01/app/oracle/db1
Inventory Location where the Oracle home registered is: /u01/app/oraInventory
Following Single Instance listener(s) will be de-configured: LISTENER
The following databases were selected for de-configuration. The databases will be deleted and will not be useful upon de-configuration : LEARN
Database unique name : LEARN
Storage used : FS
Do you want to continue (y - yes, n - no)? [n]: y
A log of this session will be written to: '/tmp/deinstall2020-11-04_02-45-53PM/logs/deinstall_deconfig2020-11-04_02-47-35-PM.out'
Any error messages from this session will be written to: '/tmp/deinstall2020-11-04_02-45-53PM/logs/deinstall_deconfig2020-11-04_02-47-35-PM.err'

######################## DECONFIG CLEAN OPERATION START ########################
Database de-configuration trace file location: /tmp/deinstall2020-11-04_02-45-53PM/logs/databasedc_clean2020-11-04_02-47-59PM.log
Database Clean Configuration START LEARN
This operation may take few minutes.
Database Clean Configuration END LEARN

Network Configuration clean config START

Network de-configuration trace file location: /tmp/deinstall2020-11-04_02-45-53PM/logs/netdc_clean2020-11-04_02-47-59PM.log

De-configuring Single Instance listener(s): LISTENER

De-configuring listener: LISTENER
    Stopping listener: LISTENER
    Warning: Failed to stop listener. Listener may not be running.
    Deleting listener: LISTENER
    Listener deleted successfully.
Listener de-configured successfully.

De-configuring Naming Methods configuration file...
Naming Methods configuration file de-configured successfully.

De-configuring Local Net Service Names configuration file...
Local Net Service Names configuration file de-configured successfully.

De-configuring backup files...
Backup files de-configured successfully.

The network configuration has been cleaned up successfully.

Network Configuration clean config END

######################### DECONFIG CLEAN OPERATION END #########################
####################### DECONFIG CLEAN OPERATION SUMMARY #######################
Successfully de-configured the following database instances : LEARN
Following Single Instance listener(s) were de-configured successfully: LISTENER
#######################################################################
############# ORACLE DECONFIG TOOL END #############

Using properties file /tmp/deinstall2020-11-04_02-45-53PM/response/deinstall_2020-11-04_02-47-35-PM.rsp
Location of logs /tmp/deinstall2020-11-04_02-45-53PM/logs/

############ ORACLE DEINSTALL TOOL START ############

####################### DEINSTALL CHECK OPERATION SUMMARY #######################
A log of this session will be written to: '/tmp/deinstall2020-11-04_02-45-53PM/logs/deinstall_deconfig2020-11-04_02-47-35-PM.out'
Any error messages from this session will be written to: '/tmp/deinstall2020-11-04_02-45-53PM/logs/deinstall_deconfig2020-11-04_02-47-35-PM.err'

######################## DEINSTALL CLEAN OPERATION START ########################
## [START] Preparing for Deinstall ##
Setting LOCAL_NODE to oraclesrv
Setting CRS_HOME to false
Setting oracle.installer.invPtrLoc to /tmp/deinstall2020-11-04_02-45-53PM/oraInst.loc
Setting oracle.installer.local to false

## [END] Preparing for Deinstall ##

Setting the force flag to false
Setting the force flag to cleanup the Oracle Base
Oracle Universal Installer clean START

Detach Oracle home '/u01/app/oracle/db1' from the central inventory on the local node : Done

Delete directory '/u01/app/oracle/db1' on the local node : Done
Delete directory '/u01/app/oraInventory' on the local node : Done
Delete directory '/u01/app/oracle' on the local node : Done
Oracle Universal Installer cleanup was successful.
Oracle Universal Installer clean END

## [START] Oracle install clean ##

## [END] Oracle install clean ##

######################### DEINSTALL CLEAN OPERATION END #########################
####################### DEINSTALL CLEAN OPERATION SUMMARY #######################
Successfully detached Oracle home '/u01/app/oracle/db1' from the central inventory on the local node.
Successfully deleted directory '/u01/app/oracle/db1' on the local node.
Successfully deleted directory '/u01/app/oraInventory' on the local node.
Successfully deleted directory '/u01/app/oracle' on the local node.
Oracle Universal Installer cleanup was successful.

Run 'rm -r /etc/oraInst.loc' as root on node(s) 'oraclesrv' at the end of the session.

Run 'rm -r /opt/ORCLfmap' as root on node(s) 'oraclesrv' at the end of the session.
Run 'rm -r /etc/oratab' as root on node(s) 'oraclesrv' at the end of the session.
Oracle deinstall tool successfully cleaned up temporary directories.
#######################################################################
############# ORACLE DEINSTALL TOOL END #############

Also Refer

Oracle 19c ASM & db installation on Linux VM

Remote Oracle Database Support

Tabs

ORA-02016: Cannot use a sub-query in START WITH on a remote database

How did we survive after infecting with covid-19 : a personal experience

Database Auto Startup in oracle 19c

Step by step installation of Oracle 19c database on Oracle Linux Virtual box

Creating new swap and data partition disk in oracle linux on virtual box

Database Errors

How To

Technology