How to Use Azure Spot Instances to Save Cloud Costs

Laila Etemadi
nOps
Published in
4 min readMar 24, 2022

Azure Spot Instances leverage unused compute capacity to help users access Microsoft cloud at a high discount. The prices of Spot Virtual Machines are 90% less than typical on-demand rates, making them an ideal cost-saving alternative.

You can use Azure Spot Instances to run temporary workloads that don’t finish within a particular period. You can use Azure Spot Instances for development, testing, and even machine learning applications.

Azure Spot Instances: Common Use Cases

Let us examine other common use cases of Azure Spot Instances.

  • Stateless Workloads: Stateless workloads can run without server memory. This state makes it easier to handle crashes and scale processes.
  • Interruptible Workloads: Spot Instances are ideal for workloads subject to interruption — for example, batch processing jobs and low-priority testing jobs.
  • Azure Spot Instances are ideal for short, scalable applications.
  • You can use Spot capacity for untimed continuous tasks.
  • Spot Instances are ideal for Continuous Integration and Continuous Delivery models (CI/CD.)

How Do Azure Spot Instances Help Reduce Cloud Spending?

Here is how Azure Spot Instances saves you cloud costs:

Provide Discounts Of Up To 90% For Workloads That Do Not Require Reliability

Microsoft Azure is the second leading cloud provider, just below AWS (Amazon Web Services), which means the Azure infrastructure has a wide range of applications, which may often get pricey. Due to the dynamic pricing model, some users can allocate excess resources.

Azure combines all extra resources as unused cloud capacity. You can access these resources through Spot Instances. Due to their volatility, spot resources are 90% cheaper than the pay-as-you-go pricing model. For example, A workload running on the B1ms Instance would cost $18 per month on the on-demand model. With Spot Instances, users pay $1.8 only.

Set A Maximum Price To Run Your Workloads

Azure lets users set a maximum price when running workloads on Spot Virtual Machines. This criterion saves on costs by eliminating excess charges on your account. Here are some of the options you can deploy:

  • If the maximum price can be equal to or greater than the current price, Azure will deploy a Spot VM (virtual machine), depending on availability.
  • Setting the maximum price less than the current price will not deploy a Spot VM.
  • If the Spot price exceeds the maximum price, Azure will evict the Virtual Machine after issuing a 30-second alert.
  • Azure will not restart the machine if the maximum price exceeds the spot price. Users have to restart their resources manually.

Choose From A Broad Range Of VMs For Your Budget

Azure has several offerings to help you deploy workloads on Spot virtual machines. These include:

  • Linux Virtual Machines: A Linux VM is highly flexible and will help your workloads adapt to a new environment. Whether you want to replicate servers or use a flexible test environment, Azure allows you to run Spot resources on Linux VMs.
  • Windows Virtual Machines: Windows Virtual Machines are compatible with other Azure products, which helps save on cost, as there is no need for allocating dedicated resources or using external services.
  • Flexible Scale Sets: This featureallows you to save on cloud costs through efficiency. With adjustable scale sets, users can alter the number of virtual machines based on the demand and availability of Spot resources.

Save Costs Long-term

One of the ways of reducing cloud costs is by choosing long-term commitments, which is possible even with Spot Instances. With the cloud, you only want to pay for what you use. You want to pay for productive hours while also eliminating non-productive workloads. According to IDC (International Data Corporation) research, a typical organization could save up to $8.5 million in 5 years by using Spot Instances.

Faster Time to Market

Due to their lower costs, Spot Instances provide a big opportunity for growth and scale. Organizations can use the temporary capacity to make products, take them to market, and get customer feedback on their MVP (Minimum Viable Product). Spot Instances can help developers prove the demand for their product before committing to long-term development.

Cons of Using Azure Spot Instances

While users can save a significant amount of costs with Spot Instances, there are common demerits with this pricing model:

  1. Microsoft does not have Service Level Agreements for Spot capacity.
  2. You will have to account for a 30-second warning before terminating Spot resources.
  3. Users cannot convert workloads from Spot resources to on-demand resources.
  4. There are price limits such that available Spot capacity depends on various factors, including region and time of the day.

To use Spot Instances, begin by setting a maximum price for running your workload. You can decide this through the price history chart on the Azure portal. Azure will let you run temporary workloads on a wide range of supported Virtual Machines.

The Bottom Line

Azure Spot Virtual Machines provide significant discounts for unused compute capacity for azure. Whether you are purchasing individual spot virtual machines or Scale Sets, you can rely on them to cut cloud spending. However, you need proper insights to ensure you are using spot instances perfectly.

nOps provides insights on how to choose Azure Virtual Machines correctly.

Start your free nOps trial to get started!

--

--