We have eight nodes under monitoring, but two of them are without data. A node has two different IPs to mysql instances in the same port (3306). So, when I added the client, I put --host, --port and --servicename. For example: pmm-admin add mysql --query-source=slowlog --username=XXXX --password=‘XXXX’ --port=3306 --host=XX.XX.XX.XX --service-name=abc1. But there are no information. Its a mysql 5.7 server (master -> slave) with slowlog enable. Thanks.
Could you check PMM Inventory page / Agents Tab?
Do they have status running?
If they do could you check if exporters are accessible from PMM Server? For it request exporters /metrics page via curl. Listening port of exporters can be learned in the same page.
If they are not, please check your firewall settings for ports 42000-51999.