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[CONTP-1782] Add appProtocol to OTLP gRPC services#3208

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tbavelier/app-protocol-field
Jul 1, 2026
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[CONTP-1782] Add appProtocol to OTLP gRPC services#3208
tbavelier merged 1 commit into
mainfrom
tbavelier/app-protocol-field

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@tbavelier tbavelier commented Jul 1, 2026 •
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What does this PR do?

Adds appProtocol: kubernetes.io/h2c to Service ports that expose OTLP/gRPC traffic:

  • Datadog Agent OTLP/gRPC local service port
  • OTel Agent standalone gRPC service port
  • OTel Agent Gateway gRPC service port

This intentionally leaves non-gRPC and OTLP/HTTP service ports unchanged.

Motivation

Fixes #2145.

Some gateways and service mesh integrations use ServicePort.appProtocol as a hint to configure upstream protocol handling. Without an HTTP/2 hint, OTLP/gRPC traffic can be proxied as HTTP/1.1 and fail with protocol errors.

This PR uses kubernetes.io/h2c instead of kgateway's http2 alias because it is the Kubernetes-defined appProtocol value for cleartext HTTP/2. OTLP/gRPC uses gRPC over HTTP/2, and these service ports are cleartext in-cluster endpoints, so kubernetes.io/h2c is both more explicit and more portable across Kubernetes-aware consumers.

References:

Additional Notes

appProtocol is only a protocol hint. It does not enforce traffic at the Kubernetes Service layer and does not change kube-proxy forwarding behavior.

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

  • Agent: N/A
  • Cluster Agent: N/A

Describe your test plan

Deploy DDA with gateway and otelAgent enabled:

spec:
  features:
    otelAgentGateway:
      enabled: true
    otelCollector:
      enabled: true

Assert the Agent and gateway k8s services (note the service names might be different as they depend on your DatadogAgent name and override) expose the appProtocol kubernetes.io/h2c for the gRPC port 4317:

╰─❯ k describe svc datadog-agent-otel-agent-gateway
Name:                     datadog-agent-otel-agent-gateway
Namespace:                system
Labels:                   app.kubernetes.io/instance=datadog-agent
                          app.kubernetes.io/managed-by=datadog-operator
                          app.kubernetes.io/name=datadog-agent-deployment
                          app.kubernetes.io/part-of=system-datadog--agent
                          app.kubernetes.io/version=
                          operator.datadoghq.com/managed-by-store=true
Annotations:              <none>
Selector:                 agent.datadoghq.com/component=otel-agent-gateway,app.kubernetes.io/part-of=system-datadog--agent
Type:                     ClusterIP
IP Family Policy:         SingleStack
IP Families:              IPv4
IP:                       10.96.123.191
IPs:                      10.96.123.191
Port:                     otlpgrpcport  4317/TCP
TargetPort:               4317/TCP
AppProtocol:              kubernetes.io/h2c
Endpoints:                10.244.1.12:4317
Port:                     otlphttpport  4318/TCP
TargetPort:               4318/TCP
Endpoints:                10.244.1.12:4318
Session Affinity:         None
Internal Traffic Policy:  Cluster
Events:                   <none>

╰─❯ k describe svc datadog-agent-agent
Name:                     datadog-agent-agent
Namespace:                system
Labels:                   app.kubernetes.io/instance=datadog-agent
                          app.kubernetes.io/managed-by=datadog-operator
                          app.kubernetes.io/name=datadog-agent-deployment
                          app.kubernetes.io/part-of=system-datadog--agent
                          app.kubernetes.io/version=
                          operator.datadoghq.com/managed-by-store=true
Annotations:              <none>
Selector:                 agent.datadoghq.com/component=agent,app.kubernetes.io/part-of=system-datadog--agent
Type:                     ClusterIP
IP Family Policy:         SingleStack
IP Families:              IPv4
IP:                       10.96.193.19
IPs:                      10.96.193.19
Port:                     traceport  8126/TCP
TargetPort:               8126/TCP
Endpoints:                10.244.0.8:8126,10.244.1.11:8126
Port:                     dogstatsdport  8125/UDP
TargetPort:               8125/UDP
Endpoints:                10.244.0.8:8125,10.244.1.11:8125
Port:                     otlpgrpcport  4317/TCP
TargetPort:               4317/TCP
AppProtocol:              kubernetes.io/h2c
Endpoints:                10.244.0.8:4317,10.244.1.11:4317
Session Affinity:         None
Internal Traffic Policy:  Local
Events:                   <none>

Checklist

  • PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
  • PR has a milestone or the qa/skip-qa label
  • All commits are signed (see: signing commits)

@tbavelier tbavelier added this to the v1.29.0 milestone Jul 1, 2026
@tbavelier tbavelier added the enhancement New feature or request label Jul 1, 2026
@tbavelier tbavelier changed the title [codex] Add appProtocol to OTLP gRPC services [CONTP-1782] Add appProtocol to OTLP gRPC services Jul 1, 2026
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@tbavelier
tbavelier marked this pull request as ready for review July 1, 2026 13:29
@tbavelier
tbavelier requested a review from a team July 1, 2026 13:29
@tbavelier
tbavelier requested a review from a team as a code owner July 1, 2026 13:29
@tbavelier
tbavelier requested review from mackjmr and removed request for a team July 1, 2026 13:29
@tbavelier
tbavelier merged commit cbf23ed into main Jul 1, 2026
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@tbavelier
tbavelier deleted the tbavelier/app-protocol-field branch July 1, 2026 15:16
@tbavelier tbavelier mentioned this pull request Jul 1, 2026
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@wdhif wdhif wdhif approved these changes
@mackjmr mackjmr mackjmr approved these changes

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enhancement New feature or request team/container-platform team/opentelemetry-agent

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Add appProtocol to otlp grpc service

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