Failed to get PMM Server parameters from local pmm-agent: pmm-agent is not connected to PMM Server.

pmm-admin add mysql --query-source=perfschema --username=pmm --password=PASSWORD --service-name=MYSQL_NODE --host=127.0.0.1 --port=3306
Failed to get PMM Server parameters from local pmm-agent: pmm-agent is not connected to PMM Server.

That can happens if you try to add some database to monitoring via pmm, but you didn’t register agent on any pmm-server. So you just need to register your agent. It can be done by following command.

pmm-admin config --server-insecure-tls --server-url=https://admin:PMM_ADMIN_PASSWORD@XXX.XXX.XXX.XXX:443 XXX.XXX.XXX.XXX generic NODE_NAME

Checking local pmm-agent status...
pmm-agent is running.
Registering pmm-agent on PMM Server...
Registered.
Configuration file /usr/local/percona/pmm2/config/pmm-agent.yaml updated.
Reloading pmm-agent configuration...
Configuration reloaded.
Checking local pmm-agent status...
pmm-agent is running.

Now you can try to add your database to pmm-server again.

pmm-admin add mysql --query-source=perfschema --username=pmm --password=PASSWORD --service-name=MYSQL_NODE --host=127.0.0.1 --port=3306

MySQL Service added.
Service ID  : /service_id/1014a471-e6bb-4fe6-960c-12610a9050fd
Service name: MYSQL_NODE

Table statistics collection enabled (the limit is 1000, the actual table count is 103).