Adds Monitor Groups docs

Author: angelampcosta

src/content/docs/load-balancing/monitors/index.mdx

@@ -31,6 +31,10 @@ For an up-to-date list of monitor properties, refer to [Monitor properties](/api
 
 For step-by-step guidance, refer to [Create monitors](/load-balancing/monitors/create-monitor/).
 
+### Monitor Groups
+
+Monitor Groups let you combine multiple health monitors into a single logical group to create more accurate, intelligent health checks for your applications. By aggregating results from several monitors, you can better reflect real application health and improve traffic steering resilience. For more details, refer to the [Monitor Groups](/load-balancing/monitors/monitor-groups/) documentation page.
+
 ---
 
 ## Health monitor regions

src/content/docs/load-balancing/monitors/monitor-groups.mdx

@@ -0,0 +1,47 @@
+---
+pcx_content_type: reference
+title: Monitor Groups
+sidebar:
+  order: 48
+
+---
+
+Group multiple health monitors together to create sophisticated health checks for your applications, ensuring more intelligent and resilient traffic steering.
+
+You can group multiple health monitors to build sophisticated health checks that more accurately reflect your application's true health. A Monitor Group allows you to combine several independent monitors, define aggregation logic, and use the collective result to determine the health of an origin pool.
+
+This enables more intelligent and resilient failover. For example, you can require that both a general API gateway monitor and a specific /login service monitor must be healthy for a pool to receive traffic.
+
+## Availability
+
+Monitor Groups are only available to customers on an Enterprise plan with the Load Balancing subscription.
+
+Configuration is available via the [API](/api/resources/load_balancers/subresources/monitor_groups/methods/create/) only.
+
+## How it works
+
+When you attach a Monitor Group to a pool, the health of that pool is determined by aggregating the results of all enabled monitors within the group.
+
+The sections below explain how monitor groups influence health status, latency, and result handling.
+
+## Endpoint health with Monitor Groups
+
+A Monitor Group determines an endpoint's health using a combination of critical monitor overrides and quorum-based consensus.
+
+**Critical Monitor Override** (`must_be_healthy`): You can designate a monitor as critical by setting `"must_be_healthy": true`. If a monitor with this setting fails its health check against an endpoint, that specific endpoint is immediately marked as unhealthy. This happens regardless of the status reported by other monitors in the group for that same endpoint. This provides a definitive override for essential services.
+
+**Quorum-Based Health**: In the absence of a failure from a `must_be_healthy` monitor, an endpoint's health is determined by a quorum of all other active monitors.
+
+- An endpoint is considered unhealthy only if more than 50% of its assigned monitors report it as unhealthy.
+- Monitors marked as `"monitoring_only": true` are excluded from the quorum calculation. They will still run and can trigger notifications, but they do not vote on the endpoint's health status.
+- Monitors marked as `disabled` will not send monitoring requests to any associated pool. They are also excluded from the quorum calculation.
+
+This quorum system prevents an endpoint from being prematurely marked as unhealthy due to a transient failure from a single, non-critical monitor.
+
+## Latency for Steering
+
+For pools using Dynamic Steering, the pool's latency is calculated as the average latency of all its enabled, non-monitoring-only monitors. This aggregated RTT (Round Trip Time) value provides a more holistic view of an origin's performance and is used to make steering decisions.
+
+## Result handling for different intervals
+
+If monitors in a group have different check intervals, the group uses the last available result from each monitor until it is refreshed. For example, if one monitor runs every 10 seconds and another every 30 seconds, the 30-second monitor's result is considered valid for the full 30 seconds until its next run completes.

src/content/docs/load-balancing/reference/load-balancing-analytics.mdx

@@ -54,6 +54,9 @@ To view latency information for your load balancer, go to **Traffic** > **Load B
 
 **Logs** provide a history of all endpoint status changes and how they affect your load balancing pools. Load Balancing only logs events that represent a status change for an endpoint, from healthy to unhealthy or vice versa.
 
+When a Monitor Group is attached to a pool, each logged health event includes the `monitors` field.
+This field lists the individual monitors within the group and their results, making it easier to see which monitor contributed to a status change.
+
 To access logs in the dashboard, go to **Traffic** > **Load Balancing Analytics**.
 
 ## GraphQL Analytics

src/content/glossary/load-balancing.yaml

@@ -11,7 +11,7 @@ entries:
     general_definition: |-
       within Cloudflare, pools represent your endpoints and how they are organized. As such, a pool can be a group of several endpoints, or you could also have only one endpoint (an origin server, for example) per pool.
 
-      If you are familiar with DNS terminology, think of a pool as a “record set,” except Cloudflare only returns addresses that are considered healthy. You can attach health monitors to individual pools for customized monitoring.
+      If you are familiar with DNS terminology, think of a pool as a “record set,” except Cloudflare only returns addresses that are considered healthy. You can attach health monitors to individual pools for customized monitoring. A pool can have either a single monitor or a monitor group attached — but not both.
 
   - term: monitor
     general_definition: |-