Silences

Temporarily mute alert notifications in Grafana

Silences temporarily suppress notifications for alerts that match specific criteria. They’re useful for planned maintenance, known issues, or reducing noise during incidents.

Silence Structure

Silence Definition

interface SilenceFormFields {
  id: string;              // Silence ID (generated)
  
  // Time range
  startsAt: string;        // ISO 8601 timestamp
  endsAt: string;          // ISO 8601 timestamp
  timeZone: TimeZone;      // Display timezone
  duration: string;        // Human-readable duration
  
  // Matching
  matchers: MatcherFieldValue[];
  
  // Metadata
  comment: string;         // Required: why this silence exists
  createdBy: string;       // Creator username
}

Silence States

Silences transition through different states:

1. Pending

   startsAt is in the future. Silence is scheduled but not yet active.

2. Active

   Current time is between startsAt and endsAt. Notifications are suppressed.

3. Expired

   endsAt is in the past. Silence is no longer active.

Label Matchers

Silences use matchers to select which alerts to suppress:

Exact Match

matchers: [
  {
    name: 'alertname',
    operator: '=',
    value: 'HighCPU'
  }
]
// Silences all alerts with alertname="HighCPU"

All matchers must match for a silence to apply (AND logic). For OR logic, create multiple silences.

Time Ranges

Setting Duration

Explicit Start/End

{
  startsAt: '2024-03-10T10:00:00Z',
  endsAt: '2024-03-10T18:00:00Z'
}

Duration Format

Supported duration formats:

• 2h - 2 hours
• 30m - 30 minutes
• 1d - 1 day
• 2h30m - 2 hours 30 minutes

Silence Metadata

Comment (Required)

Every silence must have a comment explaining its purpose:

comment: 'Planned maintenance: Database upgrade in progress'

Comments are required and help teams understand:

• Why the silence was created
• What work is being done
• Who to contact for questions

Good comment examples:

• “Deployment in progress - expected 30 mins”
• “Known issue: API rate limiting - team investigating”
• “Maintenance window: scaling cluster nodes”

Created By

Automatically populated with the creator’s username:

createdBy: '[e-mail]'

Silence with Rule Association

Silences can be associated with specific alert rules:

Rule-Specific Silence

matchers: [
  {
    name: '__rule_uid__',
    operator: '=',
    value: 'alert-rule-uid-123'
  }
]

Silence Metadata Model

Silence with Metadata

// Location: pkg/services/ngalert/models/silence.go
type SilenceWithMetadata struct {
    *Silence
    Metadata SilenceMetadata
}

type SilenceMetadata struct {
    RuleMetadata *SilenceRuleMetadata
    Permissions  *SilencePermissionSet
}

type SilenceRuleMetadata struct {
    RuleUID   string
    RuleTitle string
    FolderUID string
}

Permissions

Silences support granular permissions:

Permission Types

type SilencePermission string

const (
    SilencePermissionRead   SilencePermission = "read"
    SilencePermissionCreate SilencePermission = "create"
    SilencePermissionWrite  SilencePermission = "write"
)

Permissions are typically managed through Grafana’s RBAC system:

• alert.silences:read - View silences
• alert.silences:create - Create new silences
• alert.silences:write - Modify/delete silences

Common Patterns

Maintenance Window

{
  startsAt: '2024-03-15T02:00:00Z',
  endsAt: '2024-03-15T06:00:00Z',
  comment: 'Scheduled maintenance: Database cluster upgrade',
  matchers: [
    {
      name: 'cluster',
      operator: '=',
      value: 'production'
    },
    {
      name: 'service',
      operator: '=~',
      value: 'database.*'
    }
  ]
}

Deployment Silence

{
  startsAt: new Date().toISOString(),
  duration: '30m',
  comment: 'Deployment: API v2.5.0 rollout',
  matchers: [
    {
      name: 'service',
      operator: '=',
      value: 'api'
    },
    {
      name: 'alertname',
      operator: '=~',
      value: 'High.*|ServiceDown'
    }
  ]
}

Known Issue Silence

{
  startsAt: new Date().toISOString(),
  duration: '4h',
  comment: 'Known issue #1234: Investigating intermittent timeouts',
  matchers: [
    {
      name: 'alertname',
      operator: '=',
      value: 'HighLatency'
    },
    {
      name: 'endpoint',
      operator: '=',
      value: '/api/v1/users'
    }
  ]
}

Team-Specific Silence

{
  startsAt: new Date().toISOString(),
  duration: '2h',
  comment: 'Team offsite - reducing alert noise',
  matchers: [
    {
      name: 'team',
      operator: '=',
      value: 'frontend'
    },
    {
      name: 'severity',
      operator: '!=',
      value: 'critical'
    }
  ]
}

Frontend Components

Silence Metadata Display

// Location: public/app/features/alerting/unified/components/silences/

export const SilenceMetadataGrid = ({
  startsAt,
  endsAt,
  comment,
  createdBy
}: Props) => (
  <Stack direction="column" gap={2}>
    <MetadataRow label="Starts" value={startsAt} />
    <MetadataRow label="Ends" value={endsAt} />
    <MetadataRow label="Comment" value={comment} />
    <MetadataRow label="Created by" value={createdBy} />
  </Stack>
);

API Operations

Create Silence

POST /api/alertmanager/grafana/api/v2/silences

Body:
{
  "matchers": [
    {"name": "alertname", "value": "HighCPU", "isRegex": false, "isEqual": true}
  ],
  "startsAt": "2024-03-10T10:00:00Z",
  "endsAt": "2024-03-10T18:00:00Z",
  "comment": "Maintenance window",
  "createdBy": "alice"
}

Best Practices

Be specific with matchers

Use precise matchers to avoid silencing too many alerts. Match on multiple labels to narrow scope.

Set appropriate durations

• Deployments: 15-30 minutes
• Maintenance: Match actual window
• Investigations: 1-4 hours (extend if needed)
• Avoid silences longer than 24 hours

Write informative comments

Include:

• What work is being done
• Expected duration
• Who to contact
• Ticket/issue reference

Clean up expired silences

Regularly review and delete old silences to keep the list manageable.

Never silence critical alerts blindly

If you need to silence critical alerts, be very specific about which ones and why.

Troubleshooting

Silence not working

• Check matchers match alert labels exactly
• Verify time range includes current time
• Confirm silence state is “active” not “pending”
• Check alertmanager configuration is applied

Too many alerts silenced

• Review matchers - they may be too broad
• Use more specific label combinations
• Consider using negative matchers to exclude certain alerts

Silence expired too soon

• Check timezone settings
• Verify duration calculation
• Consider creating a new silence with extended time

Related Resources

Alert Rules

Create and manage alert rules

Notification Policies

Configure alert routing

Contact Points

Set up notification destinations

Overview

Understand the alerting architecture