Redis PHP extension for Plesk PHP 8

To install the PHP Redis extension under Plesk Obsidian for PHP 8, first log in to the Plesk server via SSH. Then execute the following commands:

Preparation

Additional packages must be installed to install the Redis extension:

apt update
apt install plesk-php80-dev plesk-php81-dev plesk-php82-dev plesk-php83-dev zlib1g-dev gcc make

Installation of the Redis extension

Carry out the installation using the pecl command:

/opt/plesk/php/8.0/bin/pecl install redis
/opt/plesk/php/8.1/bin/pecl install redis
/opt/plesk/php/8.2/bin/pecl install redis
/opt/plesk/php/8.3/bin/pecl install redis

After successful installation, the extension must be added to the PHP configuration:

echo "extension=redis.so" > /opt/plesk/php/8.0/etc/php.d/redis.ini
echo "extension=redis.so" > /opt/plesk/php/8.1/etc/php.d/redis.ini
echo "extension=redis.so" > /opt/plesk/php/8.2/etc/php.d/redis.ini
echo "extension=redis.so" > /opt/plesk/php/8.3/etc/php.d/redis.ini

To enable the new configuration via the Plesk web interface, the PHP 8 handler must be reloaded:

plesk bin php_handler --reread

The PHP handler must then be restarted in order to use the Redis extension:

# PHP 8.0
systemctl restart plesk-php80-fpm

# PHP 8.1
systemctl restart plesk-php81-fpm

# PHP 8.2
systemctl restart plesk-php82-fpm

# PHP 8.3
systemctl restart plesk-php83-fpm

Verify installation

After successful installation, check whether the variables of the Redis extension are available:

/opt/plesk/php/8.3/bin/php -i |grep redis

# Example output:
/opt/plesk/php/8.3/etc/php.d/redis.ini,
redis
redis.arrays.algorithm => no value => no value
redis.arrays.auth => no value => no value
redis.arrays.autorehash => 0 => 0
redis.arrays.connecttimeout => 0 => 0
redis.arrays.consistent => 0 => 0
redis.arrays.distributor => no value => no value
redis.arrays.functions => no value => no value
redis.arrays.hosts => no value => no value
redis.arrays.index => 0 => 0
redis.arrays.lazyconnect => 0 => 0
redis.arrays.names => no value => no value
redis.arrays.pconnect => 0 => 0
redis.arrays.previous => no value => no value
redis.arrays.readtimeout => 0 => 0
redis.arrays.retryinterval => 0 => 0
redis.clusters.auth => no value => no value
redis.clusters.cache_slots => 0 => 0
redis.clusters.persistent => 0 => 0
redis.clusters.read_timeout => 0 => 0
redis.clusters.seeds => no value => no value
redis.clusters.timeout => 0 => 0
redis.pconnect.connection_limit => 0 => 0
redis.pconnect.echo_check_liveness => 1 => 1
redis.pconnect.pool_pattern => no value => no value
redis.pconnect.pooling_enabled => 1 => 1
redis.session.lock_expire => 0 => 0
redis.session.lock_retries => 10 => 10
redis.session.lock_wait_time => 2000 => 2000
redis.session.locking_enabled => 0 => 0

The Redis extension can then be used via FPM (Apache / nginx) or via CLI.