Missing PHP extension: memcached


I have 1 LibreNMS server (non dokcer) and 2 pollers (Docker)

When I run ./validate.php I get this memcache error, but do I use it? I didn’t set this part up:

Component | Version
--------- | -------
LibreNMS  | 22.10.0-135-g7635ace4f (2022-11-20T04:10:25+00:00)
DB Schema | 2022_08_15_084507_add_rrd_type_to_wireless_sensors_table (248)
PHP       | 8.1.2-1ubuntu2.8
Python    | 3.10.6
Database  | MariaDB 10.6.7-MariaDB-2ubuntu1.1
RRDTool   | 1.7.2
SNMP      | 5.9.1

[OK]    Composer Version: 2.4.4
[OK]    Dependencies up-to-date.
[OK]    Database connection successful
[OK]    Database Schema is current
[OK]    SQL Server meets minimum requirements
[OK]    lower_case_table_names is enabled
[OK]    MySQL engine is optimal
[OK]    Database schema correct
[OK]    MySQl and PHP time match
[OK]    Distributed Polling setting is enabled globally
[OK]    Connected to rrdcached
[FAIL]  Missing PHP extension: memcached
	Please install memcached
[OK]    Active pollers found
[OK]    Dispatcher Service is enabled
[OK]    Locks are functional
[OK]    Python wrapper cron entry is not present
[OK]    Redis is functional
[OK]    rrdtool version ok
[OK]    Connected to rrdcached
[WARN]  Your local git contains modified files, this could prevent automatic updates.
	You can fix this with ./scripts/github-remove
	Modified Files:

How can fix the memcache error and also tell if we use it and not redis?

On the server I have this:

in the config file:

$config['distributed_poller']                    = true;            # Set to true to enable distributed polling
$config['distributed_poller_name']               = php_uname('n');  # Uniquely identifies the poller instance
$config['distributed_poller_group']              = 0;               # Which group to poll

However on the Pollers look to be pointing to Redis and memcache, in librenms.env

      - "REDIS_HOST="
      - "REDIS_PORT=6379"
      - "REDIS_DB=0"



Please advise what I need to check and fix this memcache error