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Azure Commitments for Elastigroup

Cloud service provider relevance: Azure Kubernetes.

Prerequisite: Before you can utilize commitments in Elastigroup, you must first purchase commitments from Azure.

Azure Commitments​

Azure Commitments are agreements you make to use a certain amount of Azure resources over a specified period, including Reserved Instances (RIs) and Savings Plans (SPs).

The types of commitments are as follows:

  • Capacity Commitments: Involve reserving VM capacity to ensure availability and predictability.
  • Cost Commitments: Involve committing to a certain spending level to benefit from discounts.

RIs are best for predictable workloads where you can commit to specific VM types and sizes, while SPs offer more flexibility for varying workloads across different services. Both options help reduce costs through committed usage, ensuring better budget management and resource allocation in Azure. You can prioritize available RIs and SPs to prevent their underutilization.

Azure Reserved Instances​

Azure RIs let you reserve VMs in Azure for a one, three, or five year term, providing significant cost savings compared to pay-as-you-go pricing, and provide the following benefits:

  • Cost Savings: Typically offers discounts of up to 72% compared to on-demand prices.
  • Predictable Billing: Helps budget and forecast costs as you pre-purchase capacity.
  • Flexibility: You can exchange or cancel RIs, providing flexibility in your commitment.

Azure Savings Plans​

Azure SPs offer a flexible pricing model that lets you save significantly on your Azure compute costs in exchange for a commitment to spend a specific amount over a one, three, or five year term and provide the following benefits:

  • Flexibility: Unlike RIs, SPs apply to a broader range of services and can adjust based on your usage patterns.
  • Automatic Savings: Automatically applies savings to eligible resources, making managing costs across multiple services easier.
  • No Commitment to Specific VM Sizes: You can switch between different VM sizes and types without losing savings.

Commitments Scenarios​

Launching a VM​

As part of the scale-up process, Elastigroup checks if an RI or SP applies to the market selection. If so, prioritizes that RI/SP.

Running Spot VMs​

As part of the revert to commitments process, Elastigroup replaces spot VMs with regular VMs and utilizes RI/SP if applicable.

Running Regular VMs​

As part of the revert to commitments process, Elastigroup utilizes RI/SP as a wrapper for a regular VM if applicable to cost savings.

Running Regular (RI/SP) VMs​

This scenario involves dynamic commitment management. Elastigroup monitors whether an RI or SP could be better utilized elsewhere. When identified, Elastigroup replaces the current instance with a spot or regular (RI/SP) VM from a different plan, following this process:

  1. A running regular VM is attached to and utilizing a specific RI or SP commitment.

  2. Elastigroup continuously monitors whether a different resource could better utilize a commitment in your Azure account to meet the configured risk percentage and strategy requirements.

  3. If conditions are met, Elastigroup initiates a replacement.

  4. Elastigroup launches either a spot VM or an alternative regular RI/SP VM to use a different plan. This maximizes commitment coverage and helps achieve optimal allocation.

The reversion will not occur if:

  • There is no alternative commitment or spot VM to revert to.
  • It violates the group's regular VM count request.