Source: http://www.syahzul.com/2016/04/06/how-to-install-oci8-on-ubuntu-14-04-and-php-5-6/
Download the Oracle Instant Client and SDK from Oracle website. (Need to login in Oracle page)
http://www.oracle.com/technetwork/topics/linuxx86-64soft-092277.html
Files: instantclient-basic-linux.x64-12.1.0.2.0.zip and instantclient-sdk-linux.x64-12.1.0.2.0.zip.
Create a new folder to store Oracle Instant Client zip files on your server.
Upload the Instant Clients files inside this folder.
mkdir /opt/oracleNow we need to extract the files.
cd /opt/oracle
unzip instantclient-basic-linux.x64-12.1.0.2.0.zip
unzip instantclient-sdk-linux.x64-12.1.0.2.0.zipNext, we need to create a symlink to Instant Client files.
ln -s /opt/oracle/instantclient_12_1/libclntsh.so.12.1 /opt/oracle/instantclient_12_1/libclntsh.so
ln -s /opt/oracle/instantclient_12_1/libocci.so.12.1 /opt/oracle/instantclient_12_1/libocci.soAdd the folder to our ldconfig.
echo /opt/oracle/instantclient_12_1 > /etc/ld.so.conf.d/oracle-instantclientUpdate the Dynamic Linker Run-Time Bindings
ldconfigDone. Now we can proceed to the next part.
To install the OCI8 extension, we need to install some additional package on our server.
Run these command:
apt-get install php-dev php-pear build-essential libaio1Once installed, we need to get the OCI8 file.
pecl install oci8When you are prompted for the Instant Client location, enter the following:
instantclient,/opt/oracle/instantclient_12_1We need to tell PHP to load the OCI8 extension.
echo "extension = oci8.so" >> /etc/php/7.1/fpm/php.ini
echo "extension = oci8.so" >> /etc/php/7.1/cli/php.iniCheck if the extension is enabled.
php -m | grep 'oci8'If returns oci8, its works!
Restart the PHP-FPM
service php7.1-fpm restartNow you can connect to Oracle DBMS from your PHP applications.
Just in some cases, on Ubuntu 16.04 and this is how someone resolved it.
Make sure you add this line extension = oci8.so to /etc/php/7.1/apache2/php.ini to make apache aware of oci8
Add the following lines to /etc/apache2/envvars
export LD_LIBRARY_PATH=/opt/oracle/instantclient_12_2
export ORACLE_HOME=/opt/oracle/instantclient_12_2
Finally restart apache2 using the command /etc/init.d/apache2 restart