Client/Server Architecture - an Overview¶
The PMM platform is based on a client-server model that enables scalability. It includes the following modules:
- PMM Client installed on every database host that you want to monitor. It collects server metrics, general system metrics, and Query Analytics data for a complete performance overview.
- PMM Server is the central part of PMM that aggregates collected data and presents it in the form of tables, dashboards, and graphs in a web interface.
The modules are packaged for easy installation and usage. It is assumed that the user should not need to understand what are the exact tools that make up each module and how they interact. However, if you want to leverage the full potential of PMM, the internal structure is important.
PMM is a collection of tools designed to seamlessly work together. Some are developed by Percona and some are third-party open-source tools.
The overall client-server model is not likely to change, but the set of tools that make up each component may evolve with the product.
The following sections illustrates how PMM is currently structured.
Each PMM Client collects various data about general system and database performance, and sends this data to the corresponding PMM Server.
The PMM Client package consist of the following:
- pmm-admin is a command-line tool for managing PMM Client, for example, adding and removing database instances that you want to monitor. For more information, see pmm-admin.
- pmm-agent is a client-side component a minimal command-line interface, which is a central entry point in charge for bringing the client functionality: it carries on client’s authentication, gets the client configuration stored on the PMM Server, manages exporters and other agents.
- node_exporter is a Prometheus exporter that collects general system metrics.
- mysqld_exporter is a Prometheus exporter that collects MySQL server metrics.
- mongodb_exporter is a Prometheus exporter that collects MongoDB server metrics.
- postgres_exporter is a Prometheus exporter that collects PostgreSQL performance metrics.
- proxysql_exporter is a Prometheus exporter that collects ProxySQL performance metrics.
To make data transfer from PMM Client to PMM Server secure, all exporters are able to use SSL/TLS encrypted connections, and their communication with the PMM server is protected by the HTTP basic authentication.
Credentials used in communication between the exporters and the PMM Server are the following ones:
- login is “pmm”
- password is equal to Agent ID, which can be seen e.g. on the Inventory Dashboard.
- How to install PMM Client
- Installing Clients
- How to pass exporter specific options when adding a monitoring service
- List of available exporter options
PMM Server runs on the machine that will be your central monitoring host. It is distributed as an appliance via the following:
- Docker image that you can use to run a container
- OVA that you can run in VirtualBox or another hypervisor
- AMI that you can run via Amazon Web Services
For more information, see Installing PMM Server.
PMM Server includes the following tools:
- Query Analytics enables you to analyze MySQL query performance over periods of
time. In addition to the client-side QAN agent, it includes the following:
- QAN API is the backend for storing and accessing query data collected by the QAN agent running on a PMM Client.
- QAN Web App is a web application for visualizing collected Query Analytics data.
- Metrics Monitor provides a historical view of metrics
that are critical to a MySQL or MongoDB server instance.
It includes the following:
- Prometheus is a third-party time-series database that connects to exporters running on a PMM Client and aggregates metrics collected by the exporters. For more information, see Prometheus Docs.
- ClickHouse is a third-party column-oriented database that facilitates the Query Analytics functionality. For more information, see ClickHouse Docs.
- Grafana is a third-party dashboard and graph builder for visualizing data
aggregated by Prometheus in an intuitive web interface. For more
information, see Grafana Docs.
- Percona Dashboards is a set of dashboards for Grafana developed by Percona.
All tools can be accessed from the PMM Server web interface (landing page). For more information, see Tools of PMM.