Internal TCP/UDP Load Balancing monitoring

Internal TCP/UDP Load Balancing exports monitoring data to Cloud Monitoring. Monitoring metrics can be used for the following purposes:

  • Evaluate an internal TCP/UDP load balancer's configuration, usage, and performance
  • Troubleshoot problems
  • Improve resource utilization and user experience

In addition to the predefined dashboards in Monitoring, you can create custom dashboards, set up alerts, and query the metrics through the Monitoring API.

Viewing Monitoring dashboards

  1. Go to Monitoring in the Google Cloud console.
    Go to Monitoring
  2. If Resources appears in the navigation pane, select Resources and then select Google Cloud Load Balancers. Otherwise, select Dashboards and then select the dashboard named Google Cloud Load Balancers.
  3. Click the name of your load balancer.

In the left pane, you can see various details for the selected load balancer. In the right pane, you can see time series graphs. Click the Breakdowns link to see specific breakdowns. The left pane presents currently configured data, while the right pane can present data served by historical configurations not currently reflected in the left pane.

Defining alerting policies

You can create alerting policies to monitor the values of metrics and to notify you when those metrics violate a condition. The following steps are for the preview alerting interface.

  1. In the Google Cloud console, go to the Monitoring page.

    Go to Monitoring

  2. In the Monitoring navigation pane, select Alerting.
  3. If you haven't created your notification channels and if you want to be notified, then click Edit Notification Channels and add your notification channels. Return to the Alerting page after you add your channels.
  4. From the Alerting page, select Create policy.
  5. To select the metric, expand the Select a metric menu and then do the following:
    1. To limit the menu to relevant entries, enter Google Cloud TCP Load Balancer or Google Cloud UDP Load Balancer into the filter bar. If there are no results after you filter the menu, then disable the Show only active resources & metrics toggle.
    2. For the Resource type, select Google Cloud TCP Load Balancer or Google Cloud UDP Load Balancer.
    3. Select a Metric category and a Metric, and then select Apply.
  6. Click Next.
  7. The settings in the Configure alert trigger page determine when the alert is triggered. Select a condition type and, if necessary, specify a threshold. For more information, see Condition trigger.
  8. Click Next.
  9. Optional: To add notifications to your alerting policy, click Notification channels. In the dialog, select one or more notification channels from the menu, and then click OK.
  10. Optional: Update the Incident autoclose duration. This field determines when Monitoring closes incidents in the absence of metric data.
  11. Optional: Click Documentation, and then add any information that you want included in a notification message.
  12. Click Alert name and enter a name for the alerting policy.
  13. Click Create Policy.
For more information, see Alerting policies.

Defining Monitoring custom dashboards

You can create custom Monitoring dashboards over Internal TCP/UDP Load Balancing metrics:

  1. Go to Monitoring in the Google Cloud console.
    Go to Monitoring
  2. Select Dashboards > Create Dashboard.
  3. Click on Add Chart.
  4. Give the chart a title.
  5. Select metrics and filters. For metrics, the resource type is Google Cloud TCP Load Balancer (Internal) Rule (internal_tcp_lb_rule) or Google Cloud UDP Load Balancer (Internal) Rule (internal_udp_lb_rule).
  6. Click Save.

Metrics for internal TCP/UDP load balancers

The following metrics for internal TCP/UDP load balancers are reported into Monitoring.

Metric Description
Inbound Throughput The number of bytes sent towards internal TCP/UDP load balancer forwarding rules, as received by the backends.
Inbound Packets The number of packets sent towards internal TCP/UDP load balancer forwarding rules, as received by the backends.
Outbound Throughput The number of bytes sent by internal load balanced backends on connections bound to forwarding rule IPs.
Outbound Packets The number of packets sent by internal load balanced backends on connections bound to forwarding rule IPs.
Latency(*) The distribution of the RTT measured for bundles of packets over each internal load balanced connection. Typically reduced to 95th-percentile in Monitoring views.

(*) Available only for TCP traffic.

Filtering dimensions for internal TCP/UDP load balancer metrics

Metrics are aggregated for each internal TCP/UDP load balancer. Metrics can be further broken down by the following dimensions:

Property Description
BACKEND NAME The name of the backend group that received the connection. The backend group can be either an instance group or a network endpoint group.
BACKEND SCOPE The scope (region or zone) of the backend that received the connection.
BACKEND ZONE If the backend was a zonal backend group, the zone of the backend that served the connection.
CLIENT NETWORK The network from which the instance that connected to internal load balancing sends traffic.
CLIENT SUBNETWORK The subnetwork from which the instance that connected to internal load balancing sends traffic.
CLIENT ZONE The Google Cloud zone of the instance that connected to the internal TCP/UDP load balancer's forwarding rule.
FORWARDING RULE The name of the forwarding rule used by the instance to connect to the internal TCP/UDP load balancer.

Metric reporting frequency and retention

Metrics for the internal TCP/UDP load balancers are exported to Monitoring 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.

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