Frequently Asked Questions

AKS Spot Instances: Cost, Use Cases & Best Practices

What are Azure Spot Instances and how do they help reduce costs in AKS?

Azure Spot Instances are virtual machines that use Azure's excess capacity, allowing you to run workloads at up to 90% less cost compared to On-Demand VMs. In AKS, they are ideal for non-critical, fault-tolerant workloads, such as batch processing or testing, where cost savings are prioritized over guaranteed availability. [Source]

What types of workloads are best suited for Spot Instances in AKS?

Spot Instances are best for non-critical, fault-tolerant workloads such as batch jobs, CI/CD processes, testing environments, and data analysis tasks that can tolerate interruptions. They are not recommended for mission-critical applications that require guaranteed uptime. [Source]

How do Spot Instances differ from On-Demand VMs in Azure?

Spot Instances offer significantly lower costs but can be evicted at any time if Azure needs the capacity, making them suitable for flexible workloads. On-Demand VMs provide guaranteed availability and are used for critical workloads where uptime is essential. [Source]

How can I add Spot Node Pools to my AKS cluster?

You can add Spot Node Pools to your AKS cluster using the Azure CLI or Portal. Ensure you have the necessary permissions and an existing AKS cluster. Set the --spot-max-price parameter to control your maximum spend. Workloads tolerant to interruptions can then be scheduled on these nodes. [Source]

What is the role of Cluster Autoscaler when using Spot Instances in AKS?

Cluster Autoscaler automatically adjusts the number of nodes in your AKS cluster based on resource demand. When Spot VMs are evicted, it helps reschedule workloads onto available nodes, including On-Demand pools, maintaining availability. [Source]

How can I minimize disruptions caused by Spot Instance evictions in AKS?

To minimize disruptions, use redundancy for critical services, implement migration tools like Velero for backups, leverage Cluster Autoscaler for rescheduling, and use Pod Disruption Budgets to control the impact of evictions. [Source]

What are best practices for scheduling workloads on Spot Instances in AKS?

Use taints and tolerations to ensure only fault-tolerant workloads are scheduled on Spot nodes. Apply node affinity and anti-affinity rules to distribute workloads and avoid single points of failure. [Source]

How does setting a maximum price for Spot VMs help manage costs?

Setting a maximum price for Spot VMs allows you to control your budget by capping the amount you are willing to pay. This ensures cost predictability and prevents unexpected spikes in cloud expenses. [Source]

Can I combine Spot and On-Demand node pools in AKS for better resiliency?

Yes, combining Spot and On-Demand node pools allows you to run non-critical workloads on Spot nodes for cost savings, while critical workloads remain on On-Demand nodes for guaranteed availability. This mixed architecture enhances both resiliency and cost efficiency. [Source]

What tools can help manage Spot Instance evictions in AKS?

Tools like KEDA (Kubernetes Event-driven Autoscaling) and Velero can help manage evictions by migrating workloads and backing up application state. Cluster Autoscaler also assists in rescheduling evicted pods to available nodes. [Source]

How can I use Scheduled Autoscaling to optimize AKS costs with Spot Instances?

Scheduled Autoscaling allows you to scale your AKS cluster up or down based on predictable workload patterns, such as increasing capacity during business hours and reducing it overnight, maximizing cost savings with Spot Instances. [Source]

What is the benefit of using Pod Disruption Budgets (PDBs) with Spot Instances?

Pod Disruption Budgets (PDBs) help ensure that critical workloads are not disrupted beyond a defined threshold during Spot Instance evictions, maintaining application stability and availability. [Source]

How does Sedai help manage Spot Instance evictions in AKS?

Sedai provides real-time monitoring and predictive scaling, automatically responding to Spot Instance evictions by rescheduling workloads to On-Demand nodes, minimizing disruptions and maintaining service continuity. [Source]

Can Sedai automate rightsizing for Spot Instances in AKS?

Yes, Sedai offers autonomous rightsizing tools that continuously analyze workload patterns and adjust resource allocation, ensuring workloads run on appropriately sized infrastructure and minimizing waste. [Source]

How can I release unused resources in AKS to save costs?

Regularly review and release idle nodes or resources that are no longer needed. Implement resource quotas to prevent over-provisioning and ensure clusters operate efficiently, reducing unnecessary cloud spend. [Source]

What is the advantage of using multi-region deployments with Spot Instances?

Multi-region deployments reduce the risk of all Spot VMs being evicted simultaneously due to regional capacity constraints, enhancing workload resilience and availability. [Source]

How can checkpoints and snapshots help with Spot Instance interruptions?

Implementing checkpoints and snapshots allows you to periodically save the state of long-running tasks. If a Spot VM is evicted, workloads can resume from the last saved state, reducing recomputation and minimizing disruption. [Source]

What are the key architectural considerations for using Spot Node Pools in AKS?

A balanced approach involves combining On-Demand and Spot node pools to maintain resiliency while cutting costs. Place mission-critical workloads on On-Demand nodes and batch jobs on Spot nodes for optimal efficiency. [Source]

How does Sedai optimize costs in AKS environments?

Sedai continuously analyzes workload patterns and implements autonomous optimization, including predictive scaling and rightsizing of Spot VMs, to maximize cost savings and operational efficiency. [Source]

What is the benefit of using autonomous optimization tools like Sedai with AKS Spot Instances?

Autonomous optimization tools like Sedai help ensure continuous rightsizing, predictive scaling, and seamless workload allocation without manual intervention, maximizing cost savings and minimizing operational overhead. [Source]

Features & Capabilities

What features does Sedai offer for cloud optimization?

Sedai offers autonomous cloud optimization, proactive issue resolution, full-stack coverage across AWS, Azure, GCP, and Kubernetes, release intelligence, plug-and-play implementation, and enterprise-grade governance. These features help reduce costs, improve performance, and enhance reliability. [Source]

Does Sedai support integration with monitoring and automation tools?

Yes, Sedai integrates with monitoring tools like Cloudwatch, Prometheus, Datadog, Azure Monitor; Kubernetes autoscalers like HPA/VPA and Karpenter; IaC and CI/CD tools like GitLab, GitHub, Bitbucket, Terraform; ITSM tools like ServiceNow and Jira; and notification tools like Slack and Microsoft Teams. [Source]

What is Sedai's approach to autonomous optimization?

Sedai uses machine learning to autonomously optimize cloud resources for cost, performance, and availability, eliminating manual intervention and continuously improving based on real application behavior. [Source]

How does Sedai ensure safe and auditable changes in cloud environments?

Sedai integrates with Infrastructure as Code (IaC), IT Service Management (ITSM), and compliance workflows, ensuring all changes are safe, validated, reversible, and auditable for enterprise-grade governance. [Source]

What modes of operation does Sedai provide?

Sedai offers three modes: Datapilot (observability), Copilot (one-click optimizations), and Autopilot (fully autonomous execution), providing flexibility for different operational needs. [Source]

Use Cases & Benefits

Who can benefit from using Sedai?

Sedai is designed for platform engineers, IT/cloud operations teams, technology leaders, site reliability engineers (SREs), and FinOps professionals in organizations with significant cloud operations across industries such as cybersecurity, IT, financial services, healthcare, travel, and e-commerce. [Source]

What business impact can customers expect from using Sedai?

Customers can achieve up to 50% cloud cost savings, 75% latency reduction, 6X productivity gains, and 50% fewer failed customer interactions. Notable results include Palo Alto Networks saving $3.5 million and KnowBe4 achieving 50% cost savings in production. [Source]

What problems does Sedai solve for cloud teams?

Sedai addresses cost inefficiencies, operational toil, performance and latency issues, lack of proactive issue resolution, complexity in multi-cloud environments, and misaligned priorities between engineering and FinOps teams. [Source]

What are some real-world success stories with Sedai?

KnowBe4 achieved 50% cost savings and saved $1.2 million on AWS; Palo Alto Networks saved $3.5 million and reduced Kubernetes costs by 46%; Belcorp reduced AWS Lambda latency by 77%; and Freshworks improved release quality and user experience. [KnowBe4], [Palo Alto Networks]

Which industries are represented in Sedai's case studies?

Sedai's case studies cover cybersecurity, IT, financial services, security awareness training, travel and hospitality, healthcare, car rental services, retail and e-commerce, SaaS, and digital commerce. [Source]

Technical Requirements & Implementation

How long does it take to implement Sedai?

Sedai's setup process takes just 5 minutes for general use cases and up to 15 minutes for specific scenarios like AWS Lambda. More complex environments may vary, and personalized onboarding is available. [Source]

How easy is it to get started with Sedai?

Sedai offers plug-and-play implementation, agentless integration via IAM, comprehensive onboarding support, detailed documentation, and a 30-day free trial for risk-free evaluation. [Source]

Where can I find technical documentation for Sedai?

Technical documentation for Sedai is available at docs.sedai.io/get-started, covering features, setup, and usage. Additional resources include case studies, datasheets, and guides at sedai.io/resources.

Security & Compliance

What security and compliance certifications does Sedai have?

Sedai is SOC 2 certified, demonstrating adherence to stringent security and data protection standards. More details are available on the Sedai Security page.

Competition & Differentiation

How does Sedai differ from other cloud optimization tools?

Sedai offers 100% autonomous optimization, proactive issue resolution, application-aware intelligence, full-stack cloud coverage, release intelligence, and rapid plug-and-play implementation. These features provide a holistic, outcome-focused approach compared to competitors that rely on static rules or manual adjustments. [Source]

What unique features set Sedai apart from competitors?

Sedai's unique features include autonomous optimization, proactive issue resolution, application-aware intelligence, release intelligence, and a quick setup process. These capabilities address specific use cases like cost optimization, performance enhancement, and operational efficiency. [Source]

Why should a customer choose Sedai over other solutions?

Customers should choose Sedai for its always-on autonomous optimization, proactive issue resolution, application-aware intelligence, full-stack coverage, safety-by-design, quick setup, and proven results such as significant cost savings and productivity gains. [Source]

Customer Proof & Social Validation

Who are some of Sedai's notable customers?

Sedai's customers include Palo Alto Networks, HP, Experian, KnowBe4, Expedia, CapitalOne Bank, GSK, and Avis, representing leaders in cybersecurity, IT, finance, healthcare, travel, and more. [Source]

What feedback have customers given about Sedai's ease of use?

Customers praise Sedai for its quick setup (5–15 minutes), agentless integration, personalized onboarding, comprehensive documentation, and risk-free 30-day trial, making adoption smooth and efficient. [Source]

Sedai Logo

AKS Spot Instances: Add Spot Node Pools and Handle Evictions

HC

Hari Chandrasekhar

Content Writer

March 24, 2025

AKS Spot Instances: Add Spot Node Pools and Handle Evictions

Featured

Cost Savings and Scalability with Spot Instances in AKS

If you're looking to scale your Kubernetes workloads efficiently without breaking the bank, Spot Instances in Azure Kubernetes might just be the solution you need. We all know that cloud computing costs can skyrocket, especially with on-demand resources. That's where Azure's Spot Instances step in. They allow you to make use of spare Azure capacity at a significantly reduced cost—up to 90% less than standard pricing. But there's a catch: Spot instances can be evicted anytime Azure needs the resources back. This makes them ideal for non-critical, fault-tolerant workloads like batch processing or testing.

In this article, you'll learn how to use spot instances effectively within Azure Kubernetes Service (AKS) to optimize costs, what to consider when implementing them, and how to deal with potential interruptions without risking your application performance.

Spot instances aren't for everyone. If you're a Kubernetes administrator or part of a DevOps team, and you're focused on maximizing efficiency while minimizing cloud costs, Spot Instances could be a great fit. These instances are also beneficial for organizations needing scalable solutions that can accommodate fluctuations in resource requirements—but who don't mind a little unpredictability in exchange for big cost savings.

Understanding Azure Spot Instances

67e10232aeef80d2da22b4ab_AD_4nXeIkIUxEr1TQLCMWyqBJtGFUnxFNXCABE9Dbtzem6jrrpe0_YXE08Z32PZUpWQnG8HcYXGTUPLYaQriPgK5nUKAU3KnBJIv7pdmSpm4I1oVhxsisc7gmi29LCJeX2KqRnfC0ZEJaw.webp

Azure Spot Virtual Machines (VMs) use excess capacity that Azure has on hand, allowing you to run workloads at a significantly reduced cost. While this is an appealing offer, the trade-off is the possibility of eviction if those resources are needed elsewhere.

Key Characteristics of Spot VMs:

  • Cost Savings: Can reduce cloud costs by up to 90% compared to On-Demand VMs.
  • Eviction Potential: Azure can revoke these instances at any time, making them unsuitable for critical applications.
  • Availability: Spot Instances are best suited for non-critical or easily restartable workloads.

Azure Spot VMs allow you to define a maximum price that you are willing to pay, which helps in managing costs predictably. Setting a price limit enables better budget management, especially if your applications can operate within the uncertainty of possible eviction.

Differences Between Spot and On-Demand VMs

  • Cost: Spot VMs cost significantly less, which is perfect for workloads that are flexible with timing.
  • Availability: On-Demand VMs offer guaranteed availability, whereas Spot VMs may be interrupted if Azure requires capacity.

Spot VMs are ideal for testing, development environments, or running jobs like rendering and batch processing. In contrast, On-Demand VMs are used when stability and guaranteed uptime are crucial for your business operations.

Imagine you are running data analysis at scale. With Spot VMs, you can schedule these workloads during non-peak hours, significantly cutting down on infrastructure expenses. On the other hand, if you are running a live website that requires 100% uptime, On-Demand instances are your best choice.

Adding Spot Node Pools to AKS: Step-by-Step Guide

To add Spot Node Pools in AKS, you'll need:

  • Azure CLI or Portal Access: You can use either method to set up Spot nodes.
  • Permissions: Ensure you have the necessary permissions to modify the cluster and create new node pools.
  • An AKS Cluster: You should have an existing AKS cluster ready to which Spot nodes can be added.

Before getting started, you need to assess your application to determine its tolerance to interruptions. This is important because spot VMs can be evicted with as little as 30 seconds' notice. Workloads that are not fault-tolerant can lead to service disruption.

Steps for Adding a Spot Node Pool to AKS

Here's how to get started using the Azure CLI:

  • Spot Max Price: Setting --spot-max-price to -1 means you're willing to pay up to the On-Demand price for the spot capacity. This helps balance cost savings with availability.

The above command creates a new node pool named SpotPool in your existing AKS cluster. With this node pool, workloads that are configured to tolerate interruptions will be scheduled on spot nodes. This way, you benefit from reduced costs while maintaining cluster functionality.

Enabling Cluster Autoscaler and Configuring Eviction Policies

To manage costs effectively and prevent downtime:

  • Cluster Autoscaler: This automatically adjusts the number of nodes in your cluster based on resource demand.
  • Eviction Policies: Setting an eviction policy helps you determine what happens when a Spot VM is evicted. You can either delete or deallocate the instance.

The Cluster Autoscaler is especially useful in conjunction with spot node pools. It ensures that if Spot VMs are evicted, workloads can quickly be rescheduled to other available nodes in the cluster. For mission-critical applications, it is also advisable to have on-demand node pools in place, so evicted workloads have a reliable fallback.

Best Practices for Scheduling and Managing Spot Instances in AKS

Spot Instances are not always reliable, so it's best to use taints and tolerations to ensure that only specific workloads are scheduled on them. This keeps essential workloads away from nodes that could be evicted.

For example, by tainting spot nodes with spot=true:NoSchedule, you can prevent high-priority pods from accidentally landing on these volatile nodes. Use tolerations for workloads that are designed to be fault-tolerant and can handle potential interruptions. This combination helps you maintain high availability for business-critical services.

Node Affinity and Anti-Affinity Rules

  • Node Affinity: Ensures workloads that can tolerate interruptions are scheduled on Spot nodes. Node affinity allows you to explicitly define that specific workloads should only run on Spot nodes by setting node labels such as spot-preferred=true.
  • Anti-Affinity Rules: Prevents workloads from being concentrated on a single node, thus avoiding a single point of failure. For instance, setting an anti-affinity rule can ensure that replicas of the same pod are distributed across multiple nodes. This is crucial in maintaining application resilience, especially when using Spot nodes that could be evicted at any moment.

Managing Evictions and Ensuring High Availability

  • Use Migration Tools: Tools like KEDA (Kubernetes Event-driven Autoscaling) can help ensure workloads are moved off Spot VMs during evictions.
  • Autoscaler Integration: Use Cluster Autoscaler to reschedule evicted pods onto On-Demand nodes when Spot nodes are terminated.

Another useful approach is implementing Pod Disruption Budgets (PDBs), which ensure that certain critical workloads are not disrupted beyond a defined threshold, even if evictions occur. This helps maintain stability in applications during unexpected interruptions.

Optimizing Costs with Spot Instances in Azure Kubernetes Service

67e102320f4bace9a1364ec7_AD_4nXf76QzjUxqWhk0Qaj9x7HTsCFkf3YXwCXAnE5X_mJLoACd0k0v73_MgG8sWbCZ5YykcOjXSWxOczCIA60YEatu8vsVEKzygCI8gsNj572YIZP2ACH6u-d4XbI-ivmz3167kxUgSPQ.webp

When adding Spot instances, you can define a maximum price you're willing to pay. This ensures that you maintain budget control without compromising on the benefits of Spot VMs.

67e18661f6d7cead7e449627_Screenshot-2025-03-24-215016.webp

Using the maximum price option helps you keep operational costs within a predictable range. For instance, if market prices rise due to higher demand, setting a price cap prevents exceeding your allocated cloud budget.

Managing Cost-Saving Strategies with Spot VMs

  • Savings Plans: Azure offers various savings plans that you can utilize alongside Spot VMs to maximize your budget efficiency. These plans provide cost predictability for workloads where consistent uptime is not a requirement.
  • Autonomous Optimization: Tools like those from Sedai help you analyze your Spot VM usage and autonomize rightsizing to ensure cost-efficiency.

Cost-saving strategies also involve identifying idle workloads and reallocating resources to Spot VMs during non-critical hours. For example, running data analysis workloads overnight, when demand is typically lower, allows you to benefit from reduced pricing.

Architectural Considerations for Spot Node Pools

67e10232a725083d45f0a73f_AD_4nXcUB_c9WDFwXWcc7awN5hhehfUuvx_oELnIn0f1PVCPaSmCM2kkuPZ4SEScRciQeEP4aZjkS4zQULOEbOApZufR4byhiQ9Eo4imojXZxycY9GLwHLq2NckZLYr9cblZSYEawG3c9A.webp

  Source: Microsoft

A balanced approach to node pools involves combining both on-demand nodes and spot nodes to maintain resiliency while cutting costs. For instance, you could place mission-critical workloads on On-Demand nodes and batch jobs on Spot nodes.

67e186a70ddae170ced9c854_Screenshot-2025-03-24-215118.webp

Mixed Node Pool Architecture: Using a mix of on-demand and spot node pools helps ensure that if Spot VMs are evicted, critical services continue to run seamlessly. This strategy minimizes downtime and ensures cost-effective use of cloud resources.

Autoscaling with Spot Node Pools

Combining Horizontal Pod Autoscaler with Cluster Autoscaler can help maintain availability even when Spot VMs are reclaimed. This allows your cluster to scale up using on-demand nodes when spot capacity drops.

To further optimize costs, consider using Scheduled Autoscaling. This involves setting predefined schedules to scale your cluster up or down based on predictable workload patterns, such as increased demand during business hours and reduced activity overnight.

Handling Spot VM Interruptions

  • Redundant Infrastructure: Always ensure you have redundancy for critical services. Evictions are inevitable, but redundancy can make them painless.
  • Migration Strategies: Use tools like Velero to back up workloads and recover them quickly. Velero allows you to create backups of both the application state and cluster resources, which can be restored in the event of an eviction.

By using multi-region deployments, you can further protect your workloads from being affected by regional capacity constraints. Deploying across multiple Azure regions reduces the risk of all Spot VMs being evicted simultaneously.

Minimizing Application Disruptions

Spot VMs can be unpredictable. Here’s how you can minimize disruptions:

  • Auto-Failover Mechanisms: Implement failover strategies to ensure that your application remains functional even when Spot VMs are evicted. This could involve rerouting traffic from affected pods to pods running on stable On-Demand nodes.
  • Checkpoints and Snapshots: Implement checkpoints to periodically save the state of long-running tasks. In case of a Spot VM eviction, workloads can resume from the last saved state, reducing the amount of recomputation needed.

Additional Cost Optimization Techniques for AKS

Choosing the right instance type and size for your workload is crucial for eliminating unnecessary costs. Oversized VMs often lead to wasted resources, while undersized VMs can cause performance issues.

67e186de8e980229ce5312b3_Screenshot-2025-03-24-215142.webp

Right-Sizing Considerations: Periodically review your workload performance metrics to determine if you're over- or under-utilizing resources. Azure's built-in monitoring tools can help you make informed decisions about resizing your VMs.

Autoscaling, Starting/Stopping Clusters, and Scaling to Zero

Configuring your AKS cluster to scale to zero during off-peak times can significantly cut costs, especially for non-production environments. Using Cluster Autoscaler to manage this is both efficient and straightforward.

You can also use Start/Stop Scheduling for non-production environments, which allows you to stop clusters during weekends or holidays when there is no expected workload, saving both compute and licensing costs.

Releasing Unused Resources

Unused resources are often the silent budget killer in cloud environments. Regularly review and release idle nodes or resources that are no longer needed. A good practice is to implement resource quotas that prevent over-provisioning and ensure that clusters are operating efficiently.

Maximize AKS Efficiency with Spot Instances and Autonomous Optimization

The benefits of Spot Instances in AKS are clear—significant cost reductions and better scalability for non-critical workloads. By adopting good architectural practices, like combining Spot and On-Demand nodes, and using tools like Cluster Autoscaler, you can enhance the resilience and cost-effectiveness of your Kubernetes workloads.

In addition, implementing redundancy strategies, leveraging taints and tolerations, and maintaining a multi-region deployment setup can greatly enhance the reliability of your infrastructure. Cost management tools and consistent monitoring further help to maximize the value obtained from Spot Instances.

For those looking to streamline management even further. Sedai, can simplify the process. They help ensure continuous rightsizing, predictive scaling, and seamless workload allocation without manual intervention.

FAQs

1. How do Spot Instances in AKS help with cost optimization? Spot instances can save up to 90% compared to on-demand VMs, making them ideal for cost-conscious environments. Learn more about managing cloud costs with Sedai's autonomous optimization here.

2. What types of workloads are suitable for Spot Instances in AKS? Spot instances are best for non-critical, fault-tolerant workloads such as batch jobs, CI/CD processes, and testing environments. Check out additional insights on choosing suitable workloads for cloud environments here.

3. How does Sedai help in managing Spot Instance evictions? Sedai provides real-time monitoring and predictive scaling that can automatically respond to evictions by rescheduling workloads to On-demand nodes, minimizing disruptions. Read about Sedai's predictive scaling capabilities here.

4. Can I use Spot Instances alongside On-Demand nodes in AKS? Absolutely. Combining spot and on-demand nodes allows you to achieve cost savings without compromising on availability for critical workloads. Learn how to design efficient cloud architectures with mixed node pools here.

5. What is the role of Cluster Autoscaler when using Spot Instances in AKS? Cluster Autoscaler helps maintain availability by automatically adjusting the number of nodes to respond to spot instance evictions. To explore how autoscalers can help you manage Kubernetes workloads effectively, visit Sedai's blog.

6. How does Sedai optimize costs in AKS?Sedai's platform continuously analyzes workload patterns to implement autonomous optimization, including predictive scaling and rightsizing of spot VMs to maximize cost savings. Discover how Sedai's automation can reduce cloud expenses here.

7. What strategies can I use to minimize disruptions caused by Spot Instance evictions? Strategies such as redundancy, using Velero for backups, and leveraging Cluster Autoscaler can help mitigate the impact of evictions. Sedai also offers solutions for autonomizing failover processes—learn more about minimizing disruptions here.

8. Is it possible to automate rightsizing with Sedai? Yes, Sedai provides tools for autonomous rightsizing, ensuring that your workloads always run on appropriately sized infrastructure, minimizing waste and reducing costs. Read more about rightsizing automation here.