Host - Check if one or more hosts are reporting to Datadog.
Metric - Compare values of a metric with a user-defined threshold.
Anomaly - Detect anomalous behavior for a metric based on historical data.
Forecast - Alert when a metric is projected to cross a threshold.
Outlier - Alert on members of a group behaving differently than the others.
Integration - Monitor metric values or health status from a specific integration.
Live Process - Check if one or more processes are running on a host.
Process Check - Watch the status produced by the process.up service check.
Network - Check the status of TCP/HTTP endpoints.
Custom Check - Monitor the status of arbitrary custom checks.
Event - Monitor events gathered by Datadog.
Logs - Monitor logs gathered by Datadog.
APM - Compare an APM metric to a user-defined threshold.
Real User Monitoring - Monitor real user data gathered by Datadog.
Watchdog - Get notified when Watchdog detects anomalous behavior.
Composite - Alert on an expression combining multiple monitors.

• Threshold Alert
• Change Alerts
• Anomaly Detection
• Outliers Alert
• Forecast Alert

• An alert is triggered whenever a metric crosses a threshold.

• An alert is triggered when the delta between values is higher than the threshold.
• A change alert evaluates the difference between a value N minutes ago and now.
• On each alert evaluation Datadog will calculate the raw difference (not absolute value) between the series now and N minutes ago then compute the average/minimum/maximum/sum over the selected period. An alert is triggered when this computed series crosses the threshold.

• An alert is triggered whenever a metric deviates from an expected pattern.
• Anomaly monitors detect when a metric is behaving differently than it has in the past, taking into account trends, seasonal day-of-week, and time-of-day patterns.
• To Detect anomalous behaviour for a metric based on historical data

• Outlier detection is an algorithmic feature that allows you to detect when a specific group is behaving different compared to its peers. For example, you could detect that one web server in a pool is processing an unusual number of requests, or significantly more 500 errors are happening in one AWS availability zone than the others.


• An alert is triggered whenever one member in a group behaves differently from its peers.

• An alert is triggered whenever a metric is forecast to cross a threshold in the future.
• Forecasting is an algorithmic feature that allows you to predict where a metric is heading in the future. It is well-suited for metrics with strong trends or recurring patterns. For example, if your application starts logging at a faster rate, forecasts can alert you a week before a disk fills up, giving you adequate time to update your log rotation policy. 

• Host Tags will automatically be added to that host's metrics and events.
• Metrics can be filtered and aggregated by Tag.
• Events can be searched by Tag.

• Tags can be any word or key:value pair, such as pool:web or test.
• Tags of the form key:value define new dimensions by which you can slice metrics or alerts.

• Certain integrations allow Datadog to automatically tag your hosts. For example:
• AWS instances will automatically be tagged with properties, including availability-zone and instance-type.
• Hosts managed by Chef will automatically be tagged with the right role.

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5. Datadog Dashboard