Grigori Melnik,Fernando Simonazzi

Microsoft patterns & practices

patterns & practices symposium 2013

Autoscaling in Windows Azureaka.ms/autoscaling

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Achieving Elasticity (prior to 11-2011)1. Manually via Windows Azure Management

Portal2. Autoscaling Service (third-party only)3. Writing your own plumbing using Azure

Management REST API

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Making Apps More ElasticTypes: instance autoscaling application throttling hybrid

Triggered by: schedules metrics

=> Autoscaling Application Block (“Wasabi”)

Other featuresScale groupsNotificationsOptimizing stabilizerPowerShell cmdlets

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Rule Types Constraint rules

Use timetables (with recurrences) to proactively set limits on #instances

Have a rank to determine precedence if there are multiple overlapping rules

Upper bound guards your budget

Lower bound guards your SLA

Reactive rules Use conditions to reactively

adjust #instances or perform some other action

Based on perf counters queue length (Azure queue) current instance count custom-defined business

metrics Help respond to unexpected

bursts or collapses in your application’s workload

Guard both your budget and SLA

DEMOWasabi in Action

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Important Remark Wasabi makes your app elastic but doesn’t make

your app scalable Design-for-scalability!

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Customizing Wasabi to your business Custom actions Custom operands/data collectors

DEMOCustomizing Wasabi to your business

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Stabilizer Dealing with the high-frequency

oscillation (the "yo-yo" problem) Supports hysteresis

Enable "cool-down" period after a scaling action during which no other scaling action can take place

Granularity: global or at the role level

Direction: up or down On by default

The user can opt-out

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Optimizing Stabilizer Making sure that scale actions correspond to the most optimal

compute hour pricing charges. Specifying intervals of time in which to execute an action

E.g. only run reactive scaling up rules during the first 15 mins of the hour

<stabilizer scaleUpCooldown="00:20:00" scaleDownCooldown="00:30:00" scaleUpOnlyInFirstMinutesOfHour="15" scaleDownOnlyInLastMinutesOfHour=“20" > <roles> … </roles> </stabilizer>

Supports for scale groups User-configurable cool down on notifications too

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How to Get All This Goodness?

Via NuGet (search key “Wasabi”) or MS Download Center

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Learning Resources Developer’s Guide Reference Documentation Tailspin Reference Implementation 14 Comprehensive Hands-on Labs 2 case studies 4 videos on Channel 9 Codeplex forum

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Case Study: MSDN/TechNet Objectives

to maximize resources utilization (from 20% to 67%)

to reduce infrastructure and running costs

to "green" the MSDN and TechNet services.

while: No code or architecture

changes Equivalent or better

performance Ease of operation Reduced on-premises

requirementsAccording to the IT Energy Efficiency Imperative (http://aka.ms/ITEEI), the biggest potential for improving the IT energy efficiency in a data center lies withincreasing server utilization.

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Resources Windows Azure Dev Center

windowsazure.com/develop/net/how-to-guides/autoscaling Wasabi home page

aka.ms/wasabi Comprehensive hands-on labs

microsoft.com/download/en/details.aspx?id=28785 CloudCover Episode on Autoscaling

http://bit.ly/cloudcover_wasabi Case studies

http://aka.ms/msdntechnetstudy and http://aka.ms/sagestudy IT Energy Efficiency Imperative http://aka.ms/ITEEI Grigori’s blog: blogs.msdn.com/agile

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Wasabi Recap: Supported Scenarios1. Autoscaling web and worker roles in Windows Azure by dynamically changing instance counts or performing application throttling.

2. Autoscaling roles based on timetables.3. Autoscaling based on metrics collected from the application and/or Windows

Azure. 4. Constraining the instance count per role by upper and lower bounds.5. Preventing fast oscillations in the number of role instances with the stabilizer.6. Optimizing costs by limiting scaling operations acknowledging billing hours.7. Monitoring and tracing autoscaling activity.8. Sending notifications to preview any scaling operations before they take place.9. Encrypting the rules and other configuration in Windows Azure blob storage or

in local file storage.10. Managing the autoscaler operation by using Windows PowerShell.11. All blocks and guidance are 100% MS IP, free and available under MS-PL.

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Thank you Questions & Answers