Build the pxc_scheduler_handler tool¶

This task guide builds pxc_scheduler_handler from source. For package manager installs, see Install Percona build of ProxySQL and the admin tools.

The pxc_scheduler_handler tool includes two main files: the pxc_scheduler_handler binary and the percona_scheduler_admin script.

The pxc_scheduler_handler binary performs the following tasks:

Evaluates the cluster state and scenario
Monitors cluster health
Performs actions, including failover during an incident

The percona_scheduler_admin script runs pxc_scheduler_handler and returns responses from the configuration file.

pxc_scheduler_handler requires percona_scheduler_admin for normal operation. Manual intervention is required without percona_scheduler_admin.

A git clone with submodules does not check out submodule content. Submodules require initialization and update before the build.

Build the scheduler submodule¶

Complete the following steps to build pxc_scheduler_handler:

Initialize git submodules:
```
$ git submodule update --init
```
Build the scheduler submodule:
```
$ build_scheduler.sh
```

The build writes the pxc_scheduler_handler binary to the repository base directory.

Do not run multiple instances of pxc_scheduler_handler. A second instance started while another instance runs causes the following results:

Additional network and system resource consumption
Identical results from both instances because both read the same configuration file

Create a MySQL admin account¶

Create an admin user account for communication between ProxySQL and pxc_scheduler_handler.

On MySQL 8.0 environments that still allow it, you can create the account with mysql_native_password:

mysql> CREATE USER 'admin'@'192.%' IDENTIFIED WITH 'mysql_native_password'
by 'admin';

ProxySQL 2.6.2 and later releases support caching_sha2_password authentication. Use this method for MySQL 9.x (where mysql_native_password is removed) and for any environment that requires SHA-2 authentication:

mysql> CREATE USER 'admin'@'192.%' IDENTIFIED WITH 'caching_sha2_password' BY 'admin';

If MySQL 9.x is the only client available on the ProxySQL host, also set mysql-default_authentication_plugin to caching_sha2_password. See Connect to ProxySQL with MySQL 9.x clients.

Grant privileges to the admin account:

mysql> GRANT ALL PRIVILEGES ON *.* TO 'admin'@'192.%' WITH GRANT OPTION;

For configuration details, see pxc_scheduler_handler overview and configuration file reference.