Configure a silence policy to filter alerts and prevent alert storms - Application Real-Time Monitoring Service - Alibaba Cloud - Application Real-Time Monitoring Service

A silence policy in ARMS Alert Management reduces alert noise and prevents alert storms. Create a silence policy to define the rules that match specific alert events, and to set the period during which the matched events are silenced.

How a silence policy works

A silence policy in ARMS Alert Management matches alert events by data source and by the tag expressions in its matching rules. An alert event that matches a silence policy is silenced during the effective period of the policy.

Important

A silence policy takes precedence over a notification policy. An alert event that is matched by a silence policy is silenced and can no longer be matched by any notification policy. For more information about how to create a notification policy, see Notification policies.

Create a silence policy

Log on to the ARMS console. In the left-side navigation pane, choose Alert Management > Silence Policies.
On the Silence Policies page, click Create Silence Policy.
On the Create Silence Policy page, enter a name for the silence policy.

In the Silent Event Matching Rule section, set the matching rules for the alert events that you want to silence.

Select a data source. The data source determines the scope of alert events that the silence policy matches.
- Specified source: The silence policy matches only the alert events that come from the sources or integrations that you specify.
- Unspecified source: The silence policy matches all alert events.

Define the expressions of the matching rules. You can define custom tags or select existing tags.

The existing tags include:

Tags from the metrics in an alert rule expression. To learn how to create tags for a Managed Service for Prometheus alert rule, see Create a Prometheus alert rule.

The ARMS system provides the following default tags.

Category	Tag	Description
Common fields	`alertname`	Alert name.
	`clustername`	Cluster name.
	`severity`	Severity level: `P1` `P2` `P3` `P4` `Default`
	`namespace`	namespace.
	`pod_name`	Pod name.
System preset fields	`_aliyun_arms_integration_name`	Integration name. The default integration name for alerts reported by ARMS is `ARMS-DEFAULT`.
	`_aliyun_arms_involvedObject_id`	Alert object ID.
	`_aliyun_arms_involvedObject_name`	Alert object name.
	`_aliyun_arms_region_id`	Region ID.
	`_aliyun_arms_alert_rule_id`	Alert rule ID.
	`_aliyun_arms_alert_type`	Alert rule type: `101`: Prometheus alert `5`: Application Monitoring alert `4`: Browser Monitoring alert
	`_arms_contact_group_v2_id`	Contact group ID (v2) for alert notifications. This tag is automatically added by ARMS to the alert event tags. Its value corresponds to the v2 contact group identifier shown on the Alarm Management > Notification Objects > Contact Group page in the console. When a notification policy is automatically created through ACK integration, this tag is used to match the policy without any manual configuration. This tag differs from the v1 `ContactGroupId` returned by the API. It is visible in the `commonLabels` field of the webhook notification payload.

Note

To require an alert to match all conditions in a rule (AND logic), click Add Condition.
To require an alert to match any rule (OR logic), click Add Rule to create a new rule.
The total configuration size of all matching rules in a notification policy cannot exceed 64 KB. This limit accommodates approximately 100 rules, depending on their complexity. Exceeding this limit causes the configuration to fail. To avoid this, create a new notification policy for additional rules.

Set the Effective Period of the silence policy.
- Persistent
- Recurring: Select Every Day or Weekly, click Add, and then set the effective time range.
- Custom Time Period: Click Add, and then set the effective time range.
Click Save.

If a silence policy matches more alert events than you intended, disable or delete the policy. For instructions, see the Manage silence policies section of this topic.

Manage silence policies

On the Silence Policies page, find the silence policy that you want to manage, and then perform any of the following operations:

Edit a silence policy: Click the name of the silence policy, or click Edit in the Actions column. After you modify the silence policy, click Save.
Enable or disable a silence policy: Turn on or turn off the switch in the Status column.
Delete a silence policy: Click Delete in the Actions column, and then click Confirm in the dialog box that appears.
Copy a silence policy: Click Copy in the Actions column.