TCP/SSL Load Balancing exports monitoring data to Stackdriver.
Monitoring metrics can be used for the following purposes:
- Evaluate a load balancer's configuration, usage, and performance
- Troubleshoot problems
- Improve resource utilization and user experience
In addition to the predefined dashboards in Stackdriver, you can create custom dashboards, set up alerts, and query the metrics through the Stackdriver monitoring API.
Viewing Stackdriver monitoring dashboards
- Go to Monitoring in the Google Cloud Platform Console.
Go to Monitoring - Select Resources > Google Cloud Load Balancers.
- Click the name of your load balancer.
In the left pane, you can see various details for this load balancer. In the right pane you can see timeseries graphs. Click the Breakdowns link to see specific breakdowns.
Metric reporting frequency and retention
Metrics for the load balancers are exported to Stackdriver in 1-minute granularity batches. Monitoring data is retained for six (6) weeks. The dashboard provides data analysis in default intervals of 1H (one hour), 6H (six hours), 1D (one day), 1W (one week), and 6W (six weeks). You can manually request analysis in any interval from 6W to 1 minute.
Metrics for TCP/SSL proxy Load Balancers
The following metrics for TCP/SSL proxy load balancers are reported into Stackdriver:
| Metric | Description |
| Inbound Traffic | The number of bytes sent from external endpoints to configured backends through the proxy (in bytes per sec). |
| Outbound Traffic |
The number of bytes sent from configured backends to external endpoints through the proxy (in bytes per sec). |
| Open Connections | The number of connections open at the given sample moment. Samples are taken one minute apart. |
| New Connections per second | The number of connections that were created (client successfully connected to backend). The counting granularity is per minute, but graphs are adjusted to show per second values. See the Stackdriver documentation for more information. |
| Closed Connections per second | The number of connections that were closed. The counting granularity is per minute, but graphs are adjusted to show per second values. See the Stackdriver documentation for more information. |
| Frontend RTT | A distribution of the smoothed RTT measured for each connection between client and proxy (measured by the proxy's TCP stack, each time application layer bytes pass from proxy to client). |
Filtering dimensions for TCP/SSL proxy metrics
Metrics are aggregated for each TCP/SSL proxy load balancer. Metrics can be further broken down by the following dimensions:
| Property | Description |
| BACKEND SCOPE | The scope (region or zone) of the instance group that served the connection. |
| BACKEND ZONE | If the instance group was a zonal instance group, the zone of the instance group that served the connection. |
| BACKEND REGION | If the instance group was a regional instance group, the region of the instance group that served the connection. |
| PROXY CONTINENT | Continent of the proxy that terminated the user TCP/SSL connection.
(Examples: America, Europe, Asia) |
| INSTANCE GROUP | The name of the instance group that received the user connection. |
| FORWARDING RULE | The name of the forwarding rule used to connect to the proxy. |
| CLIENT COUNTRY | The name of the country of the user. |
What's next
- See SSL Proxy Load Balancing Concepts for information on how SSL Proxy Load Balancing works.
- See SSL Policy Concepts for information on how SSL policies work.
- See TCP Proxy Load Balancing Concepts for information on how TCP Proxy Load Balancing works.
- See Setting Up TCP Proxy Load Balancing for information on configuring TCP Proxy Load Balancing.
