Install Oci8 ubuntu 16.04

First Prerequirements are a working apache2 and php7.2 (Ubuntu 18.04) environment.

1. Download the basic (like instantclient-basic-linux.x64-12.2.0.1.0.zip) and the SDK (instantclient-sdk-linux.x64-12.2.0.1.0.zip) package from the Oracle Website http://www.oracle.com/technetwork/database/database-technologies/instant-client/downloads/index.html
2. Upload both files to your web server, you can use WinSCP for it
3. Unzip both files on a server, in my case, you will get a new folder named "instantclient_12_2"

4a. Create a destination folder

mkdir /opt/oracle

4b. Move and rename the instantclient folder

mv instantclient_12_2 /opt/oracle/instantclient

4c. Change rights on the folder

chown -R root:www-data /opt/oracle

5. Check if you have the required packages for installing OCI8

apt install php7.2-dev php-pear build-essential libaio1

6. Create necessary soft links

ln -s /opt/oracle/instantclient/libclntsh.so.12.1 /opt/oracle/instantclient/libclntsh.so

ln -s /opt/oracle/instantclient/libocci.so.12.1 /opt/oracle/instantclient/libocci.so

7a. Add instant client to ld config files

echo /opt/oracle/instantclient > /etc/ld.so.conf.d/oracle-instantclient.conf

7b. Update Dynamic Linker Run-Time Bindings

ldconfig

8a. Now install OCI8 by pecl

pecl install oci8

8b. The OCI8 installation is asking you for the right folder

instantclient,/opt/oracle/instantclient

9a. Add oci lib to the cli php config (console php)

echo "extension = oci8.so" >> /etc/php/7.2/cli/php.ini

9b. Add oci lib to the apache php config

echo "extension = oci8.so" >> /etc/php/7.2/apache2/php.ini

10a. Set environment variables for the CLI version (you will need to reboot the server after)

echo "LD_LIBRARY_PATH=\"/opt/oracle/instantclient\"" >> /etc/environment

echo "ORACLE_HOME=\"/opt/oracle/instantclient\"" >> /etc/environment

10b. Set environment variables for the Apache version

echo "export LD_LIBRARY_PATH=\"/opt/oracle/instantclient\"" >> /etc/apache2/envvars

echo "export ORACLE_HOME=\"/opt/oracle/instantclient\"" >> /etc/apache2/envvars

11. Restart Apache

service apache2 restart

12. You're done, now you can test your connection to the Oracle database

=PHP CONNECTION EXAMPLE=

<?php
// Create connection to Oracle, change HOST IP and SID string!
$db = "(DESCRIPTION=(ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 000.000.000.000)(PORT = 1521)))(CONNECT_DATA=(SID=XXX)))";
// Enter here your username (DBUSER) and password!
$conn = oci_connect("DBUSER", "PASSWORD",$db);
if (!$conn) {
   $m = oci_error();
   echo $m['message']. PHP_EOL;
   exit;
}
else {
   print "Oracle database connection online". PHP_EOL;
}

?>