The Node is NotAvailable during opensearch update, how to fix it?

Hello,

Node Status in the instance health tab means the status of the AZ where the node belongs. We have released a new feature Multi-AZ with StandBy where the clusters are in multiple AZs with a StandBy AZ. For StandBy AZ, the node status is StandBy and for Active AZ the nodes status is Active.

As Multi-AZ with StandBy is supported for OpenSearch versions 1.3 and above. If our domain is having OpenSearch version less than 1.3 then we get NotAvailable status.

[+] Configuring a multi-AZ domain in Amazon OpenSearch Service - https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-multiaz.html

[+] https://aws.amazon.com/about-aws/whats-new/2023/05/aws-multi-az-standby-amazon-opensearch-service/

I understand currently NotAvailable status in UI can be confusing. We are aware of this issue and UI update is being rolled out in phased manner for each region to provide clear information and avoid confusion.

Regarding your Service software update query, Once you request the Service software update on your domain - the update request is received by Amazon OpenSearch service is queued and domains are updated in a phased manner to prevent simultaneous update by all the customers. You should see progress in your update request soon. If the service software update in not installed yet, please reach out to support engineering for further assistance.