Fix bug running wazuh-cluster process when it was already running

[Selutario]

Related issue
Closes #7189

Description

Hi team!

There was a bug that leads the Wazuh cluster to stop working until the manager was restarted. If wazuh-clusterd was running and the /var/ossec/bin/wazuh-clusterd was used, the socket was redefined and the process stopped working.

A condition has been added to the wazuh-clusterd.py script in order to check if the process is running before trying to launch it. In that case, the script is exited:

root@wazuh-master:/# /var/ossec/bin/wazuh-clusterd -f
2021/04/27 12:49:59 ERROR: [Cluster] [Main] Cluster is already running.

Regards,
Selu.

[davidjiglesias]

Please review possible time increment to start clusterd process with this change.

[Selutario]

Time measurement

The new code block to check if the service is already running:

    cluster_status = wazuh.core.cluster.utils.get_cluster_status()
    if cluster_status['running'] == 'yes':
        main_logger.error("Cluster is already running.")
        sys.exit(1)

The new function takes between 0.0044s and 0.0052s to execute when the condition is not met, which is negligible.

In addition, it is executed after the execution of the configuration test (/var/ossec/bin/wazuh-clusterd -t) so it is not affected/delayed.

Regards,
Selu.