Istio proxy communication not working


We are currently using Istio on AWS EKS and recently upgraded Istio from version 1.16 to 1.19 through Istio support. However, we are facing issues with functionalities that were working well on version 1.16 after the upgrade.

Specifically, we use Datadog for pod monitoring, and it seems that the Istio proxy sidecar is unable to communicate with the Datadog agent. We’ve observed logs indicating communication failures like the following:

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malt-api-8c4b969f6-z7hcp istio-proxy [2024-01-03T02:03:47.547Z] "PUT /v0.4/traces HTTP/1.1" 503 UH no_healthy_upstream - "-" 0 19 0 - "-" "okhttp/3.12.15" "a8649347-00c1-484e-a9f2-500a441fad56" "datadog-use1.datadog:8126" "-" outbound|8126||datadog-use1.datadog.svc.cluster.local - - default

It appears that there is a failure to resolve the DNS for datadog-use1.datadog, and when we try to make a call from the pod to datadog-use1.datadog:8126/info, a timeout occurs.

Why are functionalities that were working well on version 1.16 not functioning as expected after the upgrade?