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Core Concepts

RRULE Patterns

Advanced RRULE patterns and examples for scheduling recurring maintenance windows in Kener.

This guide provides comprehensive examples and patterns for using iCalendar RRULE format to schedule recurring maintenance windows.

RRULE Format Reference

Kener uses the iCalendar RRULE specification for recurring maintenance schedules.

Basic Syntax

FREQ=frequency[;INTERVAL=n][;BYDAY=days][;BYMONTHDAY=day][;COUNT=n][;UNTIL=date]

Supported Components

FREQ (Required)
title: RRULE Patterns
description: Common RRULE patterns for recurring maintenance schedules

  • WEEKLY - Weekly recurrence
  • MONTHLY - Monthly recurrence
    Kener uses iCalendar RRULE strings to schedule recurring maintenances.
    INTERVAL (Optional)

RRULE basics

  • Default: 1
    Format:
FREQ=...;[INTERVAL=n];[BYDAY=...];[BYMONTHDAY=...]

For one-time maintenances, Kener uses:
BYMONTHDAY (Optional, for MONTHLY)

FREQ=MINUTELY;COUNT=1
  • Day of month: 1-31

Common patterns

Use case RRULE
Every day FREQ=DAILY
Every Sunday FREQ=WEEKLY;BYDAY=SU
Weekdays FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
Every 2 weeks on Monday FREQ=WEEKLY;INTERVAL=2;BYDAY=MO
First day of each month FREQ=MONTHLY;BYMONTHDAY=1
  • Used for one-time maintenances

Day codes

Common Patterns

  • MO Monday
  • TU Tuesday
  • WE Wednesday
  • TH Thursday
  • FR Friday
  • SA Saturday
  • SU Sunday

Tips

  • Use simple, readable patterns.
  • Verify next occurrences in the maintenance UI preview.
  • Avoid overlapping schedules for the same monitor.
    Description: Maintenance occurs every single day at the configured time

Use Case: Daily backup windows, nightly cleanup tasks

Use Case: Bi-daily tasks

Example:

Title: System Cache Clear
Start: Monday, May 15 at 3:00 AM
RRULE: FREQ=DAILY;INTERVAL=2
Duration: 15 minutes

Occurrences:
- Mon, May 15 at 3:00 AM
- Wed, May 17 at 3:00 AM
- Fri, May 19 at 3:00 AM
- Continues every 2 days...

Every Weekday

RRULE: FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR

Description: Maintenance occurs Monday through Friday only

Use Case: Business-day maintenance windows

Example:

Title: Daily Business Hours Maintenance
Start: Monday, May 15 at 6:00 AM
RRULE: FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
Duration: 1 hour

Occurrences:
- Mon, May 15 at 6:00 AM
- Tue, May 16 at 6:00 AM
- Wed, May 17 at 6:00 AM
- Thu, May 18 at 6:00 AM
- Fri, May 19 at 6:00 AM
- Mon, May 22 at 6:00 AM (skips weekend)
- Continues Mon-Fri...

Weekly Patterns

Every Week (Single Day)

RRULE: FREQ=WEEKLY;BYDAY=SU

Description: Maintenance occurs every Sunday

Use Case: Weekly security updates, routine maintenance

Example:

Title: Weekly Security Patches
Start: Sunday, May 15 at 3:00 AM
RRULE: FREQ=WEEKLY;BYDAY=SU
Duration: 2 hours

Occurrences:
- Sun, May 15 at 3:00 AM
- Sun, May 22 at 3:00 AM
- Sun, May 29 at 3:00 AM
- Continues every Sunday...

Every Week (Multiple Days)

RRULE: FREQ=WEEKLY;BYDAY=TU,TH

Description: Maintenance occurs every Tuesday and Thursday

Use Case: Bi-weekly per week updates

Example:

Title: Database Optimization
Start: Tuesday, May 16 at 2:00 AM
RRULE: FREQ=WEEKLY;BYDAY=TU,TH
Duration: 1 hour

Occurrences:
- Tue, May 16 at 2:00 AM
- Thu, May 18 at 2:00 AM
- Tue, May 23 at 2:00 AM
- Thu, May 25 at 2:00 AM
- Continues Tue & Thu...

Bi-Weekly

RRULE: FREQ=WEEKLY;INTERVAL=2;BYDAY=MO

Description: Maintenance occurs every other Monday

Use Case: Bi-weekly deployment windows

Example:

Title: Bi-Weekly Deployment
Start: Monday, May 15 at 10:00 PM
RRULE: FREQ=WEEKLY;INTERVAL=2;BYDAY=MO
Duration: 3 hours

Occurrences:
- Mon, May 15 at 10:00 PM
- Mon, May 29 at 10:00 PM (2 weeks later)
- Mon, Jun 12 at 10:00 PM (2 weeks later)
- Continues every 2 weeks...

Every Weekend

RRULE: FREQ=WEEKLY;BYDAY=SA,SU

Description: Maintenance occurs every Saturday and Sunday

Use Case: Weekend maintenance windows

Example:

Title: Weekend Server Maintenance
Start: Saturday, May 13 at 1:00 AM
RRULE: FREQ=WEEKLY;BYDAY=SA,SU
Duration: 4 hours

Occurrences:
- Sat, May 13 at 1:00 AM
- Sun, May 14 at 1:00 AM
- Sat, May 20 at 1:00 AM
- Sun, May 21 at 1:00 AM
- Continues every weekend...

Monthly Patterns

First of Every Month

RRULE: FREQ=MONTHLY;BYMONTHDAY=1

Description: Maintenance occurs on the 1st of each month

Use Case: Monthly billing maintenance, monthly reports

Example:

Title: Monthly Billing Processing
Start: June 1, 2026 at 12:00 AM
RRULE: FREQ=MONTHLY;BYMONTHDAY=1
Duration: 2 hours

Occurrences:
- Jun 1, 2026 at 12:00 AM
- Jul 1, 2026 at 12:00 AM
- Aug 1, 2026 at 12:00 AM
- Continues monthly...

Middle of Month

RRULE: FREQ=MONTHLY;BYMONTHDAY=15

Description: Maintenance occurs on the 15th of each month

Use Case: Mid-month updates

Example:

Title: Mid-Month Database Optimization
Start: May 15, 2026 at 2:00 AM
RRULE: FREQ=MONTHLY;BYMONTHDAY=15
Duration: 3 hours

Occurrences:
- May 15, 2026 at 2:00 AM
- Jun 15, 2026 at 2:00 AM
- Jul 15, 2026 at 2:00 AM
- Continues monthly...

Last Day of Month

RRULE: FREQ=MONTHLY;BYMONTHDAY=-1

Description: Maintenance occurs on the last day of each month

Use Case: End-of-month processing

Example:

Title: End of Month Reports
Start: May 31, 2026 at 11:00 PM
RRULE: FREQ=MONTHLY;BYMONTHDAY=-1
Duration: 1 hour

Occurrences:
- May 31, 2026 at 11:00 PM
- Jun 30, 2026 at 11:00 PM
- Jul 31, 2026 at 11:00 PM
- Continues monthly...

Quarterly

RRULE: FREQ=MONTHLY;INTERVAL=3;BYMONTHDAY=1

Description: Maintenance occurs every 3 months on the 1st

Use Case: Quarterly system upgrades

Example:

Title: Quarterly System Review
Start: January 1, 2026 at 3:00 AM
RRULE: FREQ=MONTHLY;INTERVAL=3;BYMONTHDAY=1
Duration: 4 hours

Occurrences:
- Jan 1, 2026 at 3:00 AM
- Apr 1, 2026 at 3:00 AM
- Jul 1, 2026 at 3:00 AM
- Oct 1, 2026 at 3:00 AM
- Continues quarterly...

Real-World Examples

Example 1: Production Deploy Window

Scenario: Deploy updates every Tuesday and Thursday at 10 PM for 2 hours

Configuration:

Title: Production Deployment Window
Description: Bi-weekly production deployments with potential service disruption
Start Date: Tuesday, May 16, 2026 at 10:00 PM
RRULE: FREQ=WEEKLY;BYDAY=TU,TH
Duration: 7200 seconds (2 hours)
Affected Monitors:
    - API Server: DEGRADED
    - Web Frontend: DEGRADED
    - Admin Portal: MAINTENANCE

Result: Deployments every Tuesday and Thursday night, users see degraded performance notice.

Example 2: Weekend Database Maintenance

Scenario: Database optimization every Sunday at 3 AM for 3 hours

Configuration:

Title: Weekly Database Optimization
Description: Routine database maintenance including index rebuilding and cleanup
Start Date: Sunday, May 14, 2026 at 3:00 AM
RRULE: FREQ=WEEKLY;BYDAY=SU
Duration: 10800 seconds (3 hours)
Affected Monitors:
    - Primary Database: MAINTENANCE
    - API Server: DEGRADED
    - Background Jobs: DOWN

Result: Every Sunday morning, database shows maintenance while APIs show degraded.

Example 3: Monthly Security Patches

Scenario: Security patches first Sunday of each month at 2 AM for 1 hour

Configuration:

Title: Monthly Security Updates
Description: Critical security patches and system updates
Start Date: Sunday, June 4, 2026 at 2:00 AM
RRULE: FREQ=MONTHLY;BYMONTHDAY=1
Duration: 3600 seconds (1 hour)
Affected Monitors:
    - All Servers: MAINTENANCE

Note: Since RRULE doesn't support "first Sunday", use BYMONTHDAY=1 and choose first occurrence that falls on Sunday, or use BYDAY with ordinal (not supported in Kener UI currently).

Workaround: Create as weekly and manage manually or use BYMONTHDAY for specific date.

Example 4: Business Hours Backup

Scenario: Weekday backups at 6 AM for 30 minutes

Configuration:

Title: Daily Business Backup
Description: Incremental backup of business data
Start Date: Monday, May 15, 2026 at 6:00 AM
RRULE: FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
Duration: 1800 seconds (30 minutes)
Affected Monitors:
    - File Server: DEGRADED
    - Backup Service: MAINTENANCE

Result: Backups run Mon-Fri mornings, users see brief degradation notice.

Example 5: One-Time Major Upgrade

Scenario: Database migration on specific date for extended period

Configuration:

Title: Database Migration to v2.0
Description: Major database upgrade requiring extended downtime
Start Date: Saturday, June 10, 2026 at 11:00 PM
RRULE: FREQ=MINUTELY;COUNT=1
Duration: 21600 seconds (6 hours)
Affected Monitors:
    - Primary Database: DOWN
    - API Server: DOWN
    - Web Application: DOWN
    - Mobile App: DOWN

Result: One-time event on specific date/time, full outage for 6 hours.

Advanced Techniques

Combining Patterns

While a single RRULE supports one pattern, you can create multiple maintenances for complex schedules:

Scenario: Maintenance on weekends AND first of month

Solution:

Maintenance 1:
    Title: Weekend Maintenance
    RRULE: FREQ=WEEKLY;BYDAY=SA,SU

Maintenance 2:
    Title: Monthly Maintenance
    RRULE: FREQ=MONTHLY;BYMONTHDAY=1

Avoiding Holidays

RRULE doesn't support holiday exclusions directly.

Workaround:

  1. Create recurring maintenance as usual
  2. Manually cancel events that fall on holidays
  3. Or schedule maintenance to avoid common holiday dates

Time Zone Considerations

Important: Start times are stored in UTC but displayed in local timezone.

Best Practice:

  • Choose start times that work across time zones
  • Be aware of DST changes
  • Document timezone in maintenance description

Example:

Title: Global Maintenance Window
Description: Scheduled at 2 AM UTC (6 PM PST, 10 PM EST)
Start: 2:00 AM UTC

RRULE Validation

Valid RRULEs

✅ FREQ=DAILY
✅ FREQ=WEEKLY;BYDAY=MO
✅ FREQ=WEEKLY;BYDAY=MO,WE,FR
✅ FREQ=WEEKLY;INTERVAL=2;BYDAY=SU
✅ FREQ=MONTHLY;BYMONTHDAY=1
✅ FREQ=MINUTELY;COUNT=1

Invalid RRULEs

❌ FREQ=WEEKLY (missing BYDAY for weekly)
❌ BYDAY=MO (missing FREQ)
❌ FREQ=YEARLY (yearly not supported)
❌ FREQ=HOURLY (hourly not supported)
❌ FREQ=WEEKLY;BYDAY= (empty BYDAY)

Common Errors

Error: "BYDAY required for WEEKLY frequency"

Problem: FREQ=WEEKLY without BYDAY
Solution: Add BYDAY=MO,TU,WE,TH,FR,SA,SU or specific days

Error: "Invalid RRULE format"

Problem: Syntax error in RRULE
Solution: Check semicolons, equals signs, comma separators

Testing Your RRULE

Using Dashboard Preview

The maintenance creation form shows the generated RRULE at the bottom:

  1. Configure frequency, interval, days
  2. Check "Generated RRULE" preview
  3. Verify it matches your intent

Checking Generated Events

After creating a maintenance:

  1. View the maintenance edit page
  2. Scroll to "Maintenance Events" section
  3. Verify events appear on expected dates/times

Online RRULE Tools

Test your RRULE with external tools:

Note: Paste your RRULE with DTSTART prefix:

DTSTART:20260515T030000Z
RRULE:FREQ=WEEKLY;BYDAY=SU

Troubleshooting

Problem: Events not generating as expected

Solutions:

  • Verify RRULE syntax is correct
  • Check maintenance status is ACTIVE
  • Wait for hourly scheduler to run
  • Verify start_date_time is reasonable

Problem: Wrong days selected

Solutions:

  • Check BYDAY codes (MO=Monday, TU=Tuesday, etc.)
  • Verify no typos in day codes
  • Remember to separate multiple days with commas

Problem: Events appearing on wrong dates

Solutions:

  • Check start_date_time is correct
  • Verify time zone interpretation
  • Confirm INTERVAL matches expectation

Best Practices

Keep It Simple:

✅ FREQ=WEEKLY;BYDAY=SU
❌ Complex patterns that are hard to explain

Document Complex Schedules:

Title: Bi-Weekly Tue/Thu Deployment
Description: |
    Occurs every other week on Tuesday and Thursday
    RRULE: FREQ=WEEKLY;INTERVAL=2;BYDAY=TU,TH

Test Before Production:

1. Create maintenance with INACTIVE status
2. Verify events generate correctly
3. Check dates and times
4. Set to ACTIVE when confirmed

Use Descriptive Titles:

✅ "Weekly Sunday 3AM Security Updates"
❌ "Maintenance"

Reference Card

Quick Reference:

Pattern RRULE
One-time FREQ=MINUTELY;COUNT=1
Every day FREQ=DAILY
Every other day FREQ=DAILY;INTERVAL=2
Weekdays FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
Every Sunday FREQ=WEEKLY;BYDAY=SU
Bi-weekly Mondays FREQ=WEEKLY;INTERVAL=2;BYDAY=MO
First of month FREQ=MONTHLY;BYMONTHDAY=1
15th of month FREQ=MONTHLY;BYMONTHDAY=15
Quarterly FREQ=MONTHLY;INTERVAL=3;BYMONTHDAY=1

Day Codes:

  • MO = Monday
  • TU = Tuesday
  • WE = Wednesday
  • TH = Thursday
  • FR = Friday
  • SA = Saturday
  • SU = Sunday

Next Steps