update container-insights-custom-metrics]

Author: bwren

articles/azure-monitor/containers/container-insights-custom-metrics.md

@@ -14,8 +14,8 @@ Container insights collects [custom metrics](../essentials/metrics-custom-overvi
 - Pin performance charts in Azure portal dashboards.
 - Take advantage of [metric alerts](../alerts/alerts-types.md#metric-alerts).
 
-> [!NOTE]
-> This article describes collection of custom metrics from Kubernetes clusters. You can also collect Prometheus metrics as described in [Collect Prometheus metrics with Container insights](container-insights-prometheus.md).
+> [!IMPORTANT]
+> These metrics will no longer be collected starting May 31, 2024 as described in [Container insights recommended alerts (custom metrics) (preview) retirement moving up to 31 May 2024](https://azure.microsoft.com/updates/container-insights-recommended-alerts-custom-metrics-preview-retirement-moving-up-to-31-may-2024). See [Enable Prometheus and Grafana](kubernetes-monitoring-enable.md#enable-prometheus-and-grafana) to enable collection of Prometheus metrics.
 
 ## Use custom metrics
 Custom metrics collected by Container insights can be accessed with the same methods as custom metrics collected from other data sources, including [metrics explorer](../essentials/metrics-getting-started.md) and [metrics alerts](../alerts/alerts-types.md#metric-alerts).