[feat][doc] add metrics for extensible load balancer (#646)

docs/reference-metrics.md

@@ -350,32 +350,59 @@ All the loadbalancing metrics are labeled with the following labels:
 - broker: broker=${broker}. ${broker} is the IP address of the broker
 - metric: metric="loadBalancing".
 
+:::note
+
+Metrics with an asterisk (*) are only available in the **extensible** load balancer.
+
+:::
+
 | Name | Type | Description |
 | --- | --- | --- |
 | pulsar_lb_bandwidth_in_usage | Gauge | The broker inbound bandwidth usage (in percent). |
 | pulsar_lb_bandwidth_out_usage | Gauge | The broker outbound bandwidth usage (in percent). |
 | pulsar_lb_cpu_usage | Gauge | The broker cpu usage (in percent). |
 | pulsar_lb_directMemory_usage | Gauge | The broker process direct memory usage (in percent). |
 | pulsar_lb_memory_usage | Gauge | The broker process memory usage (in percent). |
+| pulsar_lb_resource_usage {feature=max}* |Gauge|The max resource usage of the bandwidth, CPU, memory, and direct_memory.|
+| pulsar_lb_resource_usage {feature=max_ema}* | Gauge | The broker load score (WeightedMaxEMA).|
 
 ### BundleUnloading metrics
 All the bundleUnloading metrics are labeled with the following labels:
 - cluster: cluster=${pulsar_cluster}. ${pulsar_cluster} is the cluster name that you have configured in the `broker.conf` file.
+- bundle: bundle=${bundle}. ${bundle} is the bundle range on this broker.
 - metric: metric="bundleUnloading".
 
+:::note
+
+Metrics with an asterisk (*) are only available in the **extensible** load balancer.
+
+:::
+
 | Name | Type | Description |
 |-------------------------------|---------|----------------------------------------------|
 | pulsar_lb_unload_broker_total | Counter | Unload broker count in this bundle unloading |
 | pulsar_lb_unload_bundle_total | Counter | Bundle unload count in this bundle unloading |
+| pulsar_lb_unload_broker_breakdown_total{result, reason}* | Counter | Unload broker breakdown count grouped by result and reason labels.|
+| pulsar_lb_resource_usage_stats{feature=max_ema, stat=avg}* | Gauge | The average of brokers' load scores.|
+| pulsar_lb_resource_usage_stats{feature=max_ema, stat=std}* | Gauge | The standard deviation of brokers' load scores. |
 
 ### BundleSplit metrics
 All the bundleUnloading metrics are labeled with the following labels:
 - cluster: cluster=${pulsar_cluster}. ${pulsar_cluster} is the cluster name that you have configured in the `broker.conf` file.
+- bundle: bundle=${bundle}. ${bundle} is the bundle range on this broker.
 - metric: metric="bundlesSplit".
 
+:::note
+
+Metrics with an asterisk (*) are only available in the **extensible** load balancer.
+
+:::
+
 | Name | Type | Description |
 |-------------------------------|---------|------------------------------------------------------------|
 | pulsar_lb_bundles_split_total | Counter | The total count of bundle split in this leader broker |
+| pulsar_lb_bundles_split_breakdown_total{result, reason}* | Counter | Bundle split breakdown count grouped by the result and reason labels.|
+
 
 ### Bundle metrics
 All the bundle metrics are labeled with the following labels:
@@ -394,6 +421,49 @@ All the bundle metrics are labeled with the following labels:
 | pulsar_bundle_msg_throughput_in | Gauge | The total throughput coming into the topics in this bundle (byte per second). |
 | pulsar_bundle_msg_throughput_out | Gauge | The total throughput going out from the topics in this bundle (byte per second). |
 
+### Bundle assign metrics
+
+All the bundle assign metrics are labeled with the following labels:
+
+- cluster: cluster=${pulsar_cluster}. ${pulsar_cluster} is the cluster name you have configured in the `broker.conf` file.
+- broker: broker=${broker}. ${broker} is the IP address of the broker.
+- bundle: bundle=${bundle}. ${bundle} is the bundle range on this broker.
+- metric: metric="assign".
+
+:::note
+
+Metrics with an asterisk (*) are only available in the **extensible** load balancer.
+
+:::
+
+Name | Type | Description
+|---|---|---
+pulsar_lb_assign_broker_breakdown_total{result, reason}*|Counter| Assign broker breakdown count grouped by result and reason labels.|
+
+### Service unit state channel metrics
+
+All the service unit state channel metrics are labeled with the following labels:
+
+- cluster: cluster=${pulsar_cluster}. ${pulsar_cluster} is the cluster name you have configured in the `broker.conf` file.
+- metric: metric="sunitStateChn".
+
+:::note
+
+Metrics with an asterisk (*) are only available in the **extensible** load balancer.
+
+:::
+
+Name | Type | Description
+|---|---|---
+pulsar_sunit_state_chn_owner_lookup_total{result, state}*|Counter|The owner broker lookup counts grouped by the result and state labels.
+pulsar_sunit_state_chn_event_publish_ops_total{result, event}*|Counter|The published message count of service unit (e.g., bundle) state changes grouped by the result and event labels
+pulsar_sunit_state_chn_subscribe_ops_total{result, event}*|Counter|The subscribed message count of service unit (e.g., bundle) state changes grouped by the result and event labels.
+pulsar_sunit_state_chn_inactive_broker_cleanup_ops_total{result}*|Counter|The counts of inactive broker cleanup operations grouped by the result label.
+pulsar_sunit_state_chn_orphan_su_cleanup_ops_total*|Counter|The total count of orphan service unit (e.g., bundle) cleanup operations.
+pulsar_sunit_state_chn_owned_su_total*|Gauge|The number of owned bundles.
+pulsar_sunit_state_chn_su_tombstone_cleanup_ops_total*|Counter|The total count of deleted service units (e.g., bundles) tombstone operations.
+pulsar_sunit_state_chn_cleanup_ops_total{result=Failure}*|Counter|The total count of cleanup operation failures.
+
 ### Subscription metrics
 
 > Subscription metrics are only exposed when `exposeTopicLevelMetricsInPrometheus` is set to `true`.