Cost when changing Opensearch configurations without Blue/green deployment

When using the new feature that allows certain configuration changes in Amazon OpenSearch Service without requiring a blue/green deployment, there is typically no additional cost associated with these updates. This new capability is designed to make changes faster and with minimal disruption to your cluster operations.

The primary benefit of this approach is that it avoids the need for additional resources that were previously required during blue/green deployments. In a blue/green deployment scenario, you would incur extra costs for maintaining both environments during the transition period, typically for the first hour.

However, with the new feature, you can make specific changes such as updating cluster volume size, volume type, IOPS, throughput, the number of data nodes (in certain scenarios), and cluster manager (master) node configurations without initiating a blue/green deployment. This means you can avoid the additional resource utilization and associated costs that come with blue/green deployments.

It's important to note that this cost-saving benefit applies to supported changes only. Some modifications, such as simultaneously changing both the data node instance type and count, or decreasing storage volume size, will still require a blue/green deployment and may incur additional costs.

To ensure you're making a change that doesn't require a blue/green deployment (and thus avoids additional costs), you can use the dry-run option provided by Amazon OpenSearch Service. This will help you determine whether your specific change can be made without a blue/green deployment before you commit to the change.
Sources
Alternative to the blue green deployment in Opensearch | AWS re:Post
Amazon OpenSearch Service now lets you update cluster volume without blue/green
Amazon OpenSearch Service now lets you update node count without blue/green
Amazon OpenSearch Service now lets you update cluster manager nodes without blue/green