AKS Communications across regions and VNEt peering

Question

Hi, we have an AKS cluster which has Postgres deployed in it. We want to deploy the same cluster to a paired region, but the two Postgres servers must be able to see and talk to each other. Do we need to implement peering between the VNets in each region in order for the two Postgres pods in AKS to see and talk to each other?

Thanks ahead of time

Answer 1

@richardwolford-7948 , Thank you for your question.

Please do correct me if I am wrong. AKS cluster A with Postgres workload instance A is deployed in Azure region A and AKS cluster B with Postgres workload instance B is deployed in Azure region B. You want Postgres workload instance A and Postgres workload instance B to be able to talk to each other.

• Postgres A and Postgres B can communicate with each other over the public internet if you are exposing both of them using Services of ServiceType LoadBalancer or a public Ingress. [Reference]
• If you want Postgres A and Postgres B to talk over a secure tunnel on the internet, you can connect the Virtual Networks of the two AKS clusters using Azure VNet-to-VNet VPN
• If you want Postgres A and postgres B to talk to each other over private internet, you can peer the Virtual Networks of the two AKS clusters.

You can also refer to AKS Baseline for multi-region clusters and Network Topology in Baseline architecture for AKS Clusters.

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Hope this helps.

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Answer 2

Hi @richardwolford-7948

Yes, choose two regions paired together.

An AKS cluster is deployed into a single region. To protect your system from region failure, deploy your application into multiple AKS clusters across different regions. When planning where to deploy your AKS cluster, consider:

AKS region availability
Choose regions close to your users.
AKS continually expands into new regions.
Azure paired regions
For your geographic area, choose two regions paired together.
AKS platform updates (planned maintenance) are serialized with a delay of at least 24 hours between paired regions.
Recovery efforts for paired regions are prioritized where needed.
Service availability
Decide whether your paired regions should be hot/hot, hot/warm, or hot/cold.
Do you want to run both regions at the same time, with one region ready to start serving traffic? Or,
Do you want to give one region time to get ready to serve traffic?

for more details
https://learn.microsoft.com/en-us/azure/aks/operator-best-practices-multi-region

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Answer 3

Hello, thank you for your response. We are running hot/hot with a front door directing traffic for us. BUT, with two AKS clusters, which we have, how would one cluster's pods talk to the pods in the second AKS cluster? Would they talk to each other using the external load balancer of the other AKS cluster, or would pairing the regions allow them to talk to each other directly? My guess is that we would use the external load balancers.

Thanks,

Richard