Notice:
This is the "latest" release of Envoy Gateway, which contains the most recent commits from the main branch.
This release might not be stable.
Please refer to the /docs documentation for the most current information.

Proxy Access Logs

7 minute read

Envoy Gateway provides observability for the ControlPlane and the underlying EnvoyProxy instances. This task show you how to config proxy access logs.

Prerequisites

Install Envoy Gateway

Follow the steps below to install Envoy Gateway and the example manifest. Before proceeding, you should be able to query the example backend using HTTP.

Expand for instructions

Install the Gateway API CRDs and Envoy Gateway using Helm:
Gateway API CRD compatibility
This command installs Gateway API CRDs. If your Kubernetes provider already manages compatible Gateway API CRDs for the cluster, use the provider-managed Gateway API CRD install steps instead.
```
helm install eg oci://docker.io/envoyproxy/gateway-helm --version v0.0.0-latest -n envoy-gateway-system --create-namespace
```

Install the GatewayClass, Gateway, HTTPRoute and example app:

kubectl apply -f https://github.com/envoyproxy/gateway/releases/download/latest/quickstart.yaml -n default

Verify Connectivity:

Get the External IP of the Gateway:

export GATEWAY_HOST=$(kubectl get gateway/eg -o jsonpath='{.status.addresses[0].value}')

Curl the example app through Envoy proxy:

curl --verbose --header "Host: www.example.com" http://$GATEWAY_HOST/get

The above command should succeed with status code 200.

Get the name of the Envoy service created the by the example Gateway:

export ENVOY_SERVICE=$(kubectl get svc -n envoy-gateway-system --selector=gateway.envoyproxy.io/owning-gateway-namespace=default,gateway.envoyproxy.io/owning-gateway-name=eg -o jsonpath='{.items[0].metadata.name}')

Get the deployment of the Envoy service created the by the example Gateway:

export ENVOY_DEPLOYMENT=$(kubectl get deploy -n envoy-gateway-system --selector=gateway.envoyproxy.io/owning-gateway-namespace=default,gateway.envoyproxy.io/owning-gateway-name=eg -o jsonpath='{.items[0].metadata.name}')

Port forward to the Envoy service:

kubectl -n envoy-gateway-system port-forward service/${ENVOY_SERVICE} 8888:80 &

Curl the example app through Envoy proxy:

curl --verbose --header "Host: www.example.com" http://localhost:8888/get

The above command should succeed with status code 200.

Install Add-ons

Envoy Gateway provides an add-ons Helm chart to simplify the installation of observability components.
The documentation for the add-ons chart can be found here.

Follow the instructions below to install the add-ons Helm chart.

helm install eg-addons oci://docker.io/envoyproxy/gateway-addons-helm --version v0.0.0-latest -n monitoring --create-namespace

By default, the OpenTelemetry Collector is disabled. To install add-ons with OpenTelemetry Collector enabled, use the following command.

helm install eg-addons oci://docker.io/envoyproxy/gateway-addons-helm --version v0.0.0-latest --set opentelemetry-collector.enabled=true -n monitoring --create-namespace

By default, the Service type of loki is ClusterIP, you can change it to LoadBalancer type for further usage:

kubectl patch service loki -n monitoring -p '{"spec": {"type": "LoadBalancer"}}'

Expose endpoints:

LOKI_IP=$(kubectl get svc loki -n monitoring -o jsonpath='{.status.loadBalancer.ingress[0].ip}')

Default Access Log

If custom format string is not specified, Envoy Gateway uses the following default format:

{
  "start_time": "%START_TIME%",
  "method": "%REQ(:METHOD)%",
  "x-envoy-origin-path": "%REQ(X-ENVOY-ORIGINAL-PATH?:PATH)%",
  "protocol": "%PROTOCOL%",
  "response_code": "%RESPONSE_CODE%",
  "response_flags": "%RESPONSE_FLAGS%",
  "response_code_details": "%RESPONSE_CODE_DETAILS%",
  "connection_termination_details": "%CONNECTION_TERMINATION_DETAILS%",
  "upstream_transport_failure_reason": "%UPSTREAM_TRANSPORT_FAILURE_REASON%",
  "bytes_received": "%BYTES_RECEIVED%",
  "bytes_sent": "%BYTES_SENT%",
  "duration": "%DURATION%",
  "x-envoy-upstream-service-time": "%RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)%",
  "x-forwarded-for": "%REQ(X-FORWARDED-FOR)%",
  "user-agent": "%REQ(USER-AGENT)%",
  "x-request-id": "%REQ(X-REQUEST-ID)%",
  ":authority": "%REQ(:AUTHORITY)%",
  "upstream_host": "%UPSTREAM_HOST%",
  "upstream_cluster": "%UPSTREAM_CLUSTER%",
  "upstream_local_address": "%UPSTREAM_LOCAL_ADDRESS%",
  "downstream_local_address": "%DOWNSTREAM_LOCAL_ADDRESS%",
  "downstream_remote_address": "%DOWNSTREAM_REMOTE_ADDRESS%",
  "requested_server_name": "%REQUESTED_SERVER_NAME%",
  "route_name": "%ROUTE_NAME%"
}

Note: Envoy Gateway disable envoy headers by default, you can enable it by setting EnableEnvoyHeaders to true in the ClientTrafficPolicy CRD.

Verify logs from loki:

curl -s "http://$LOKI_IP:3100/loki/api/v1/query_range" --data-urlencode "query={job=\"fluentbit\"}" | jq '.data.result[0].values'

Disable Access Log

If you want to disable it, set the telemetry.accesslog.disable to true in the EnvoyProxy CRD.

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: eg
spec:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller
  parametersRef:
    group: gateway.envoyproxy.io
    kind: EnvoyProxy
    name: disable-accesslog
    namespace: envoy-gateway-system
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: disable-accesslog
  namespace: envoy-gateway-system
spec:
  telemetry:
    accessLog:
      disable: true
EOF

OpenTelemetry Sink

Envoy Gateway can send logs to OpenTelemetry Sink.

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: eg
spec:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller
  parametersRef:
    group: gateway.envoyproxy.io
    kind: EnvoyProxy
    name: otel-access-logging
    namespace: envoy-gateway-system
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: otel-access-logging
  namespace: envoy-gateway-system
spec:
  telemetry:
    accessLog:
      settings:
        - format:
            type: Text
            text: |
              [%START_TIME%] "%REQ(:METHOD)% %REQ(X-ENVOY-ORIGINAL-PATH?:PATH)% %PROTOCOL%" %RESPONSE_CODE% %RESPONSE_FLAGS% %BYTES_RECEIVED% %BYTES_SENT% %DURATION% "%REQ(X-FORWARDED-FOR)%" "%REQ(USER-AGENT)%" "%REQ(X-REQUEST-ID)%" "%REQ(:AUTHORITY)%" "%UPSTREAM_HOST%"
          sinks:
            - type: OpenTelemetry
              openTelemetry:
                host: otel-collector.monitoring.svc.cluster.local
                port: 4317
                resources:
                  k8s.cluster.name: "cluster-1"
EOF

Verify logs from loki:

curl -s "http://$LOKI_IP:3100/loki/api/v1/query_range" --data-urlencode "query={exporter=\"OTLP\"}" | jq '.data.result[0].values'

gGRPC Access Log Service(ALS) Sink

Envoy Gateway can send logs to a backend implemented gRPC access log service proto. There’s an example service here, which simply count the log and export to prometheus endpoint.

The following configuration sends logs to the gRPC access log service:

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: eg
spec:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller
  parametersRef:
    group: gateway.envoyproxy.io
    kind: EnvoyProxy
    name: als
    namespace: envoy-gateway-system
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: als
  namespace: envoy-gateway-system
spec:
  telemetry:
    accessLog:
      settings:
        - sinks:
            - type: ALS
              als:
                backendRefs:
                  - name: otel-collector
                    namespace: monitoring
                    port: 9000
                type: HTTP
EOF

Verify logs from envoy-als:

curl -s "http://$LOKI_IP:3100/loki/api/v1/query_range" --data-urlencode "query={exporter=\"OTLP\"}" | jq '.data.result[0].values'

Buffering for gRPC Sinks

The OpenTelemetry and ALS sinks both stream over gRPC, and Envoy buffers log entries before flushing them. By default it flushes every 1s or once 16384 bytes of entries have accumulated, whichever comes first.

sizeBytes is a soft limit on the entry buffer: when buffered entries exceed it, Envoy flushes early instead of waiting for flushInterval. Entries are discarded — and counted by the sink’s logs_dropped stat — only when that flush cannot drain the buffer, which is what happens while the sink is unavailable. Raising it trades proxy memory for a larger batch, so size it from your own measured entry size and request rate.

The two settings together determine how much of a sink outage you can absorb, and they have to be tuned as a pair. Entries survive an outage only for as long as they stay buffered: a flush that fires while the sink is unreachable loses the batch it was carrying. So flushInterval has to be longer than the outage you want to ride out, and sizeBytes large enough to hold the entries that arrive during it — whichever limit is reached first ends the window. Leaving flushInterval at its 1s default means a flush is attempted every second, so raising sizeBytes on its own will not widen that window.

Both settings are configured per sink under buffer:

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: eg
spec:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller
  parametersRef:
    group: gateway.envoyproxy.io
    kind: EnvoyProxy
    name: accesslog-buffer
    namespace: envoy-gateway-system
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: accesslog-buffer
  namespace: envoy-gateway-system
spec:
  telemetry:
    accessLog:
      settings:
        - sinks:
            - type: OpenTelemetry
              openTelemetry:
                backendRefs:
                  - name: otel-collector
                    namespace: monitoring
                    port: 4317
                buffer:
                  flushInterval: 5s
                  sizeBytes: 16Mi
            - type: ALS
              als:
                backendRefs:
                  - name: envoy-als
                    namespace: monitoring
                    port: 9000
                type: HTTP
                buffer:
                  sizeBytes: 4Mi
EOF

sizeBytes accepts a plain byte count or a quantity suffix (256Ki, 4Mi, 1Gi). Envoy carries it as a 32-bit unsigned integer, so 4Gi and above is rejected — with the Gateway reported as not accepted — when the EnvoyProxy is translated. flushInterval must be greater than zero. Anything left unset keeps Envoy’s default.

CEL Expressions

Envoy Gateway provides CEL expressions to filter access log .

For example, you can use the expression 'x-envoy-logged' in request.headers to filter logs that contain the x-envoy-logged header.

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: eg
spec:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller
  parametersRef:
    group: gateway.envoyproxy.io
    kind: EnvoyProxy
    name: otel-access-logging
    namespace: envoy-gateway-system
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: otel-access-logging
  namespace: envoy-gateway-system
spec:
  telemetry:
    accessLog:
      settings:
        - format:
            type: Text
            text: |
              [%START_TIME%] "%REQ(:METHOD)% %REQ(X-ENVOY-ORIGINAL-PATH?:PATH)% %PROTOCOL%" %RESPONSE_CODE% %RESPONSE_FLAGS% %BYTES_RECEIVED% %BYTES_SENT% %DURATION% "%REQ(X-FORWARDED-FOR)%" "%REQ(USER-AGENT)%" "%REQ(X-REQUEST-ID)%" "%REQ(:AUTHORITY)%" "%UPSTREAM_HOST%"
          matches:
            - "'x-envoy-logged' in request.headers"
          sinks:
            - type: OpenTelemetry
              openTelemetry:
                host: otel-collector.monitoring.svc.cluster.local
                port: 4317
                resources:
                  k8s.cluster.name: "cluster-1"
EOF

Verify logs from loki:

curl -s "http://$LOKI_IP:3100/loki/api/v1/query_range" --data-urlencode "query={exporter=\"OTLP\"}" | jq '.data.result[0].values'

Gateway API Metadata

Envoy Gateway provides additional metadata about the K8s resources that were translated to certain envoy resources. For example, details about the HTTPRoute and GRPCRoute (kind, group, name, namespace and annotations) are available for access log formatter using the METADATA operator.

To enrich logs, users can add log operator that refer to XDS metadata, such as:

%METADATA(ROUTE:envoy-gateway:resources)%
%CEL(xds.route_metadata.filter_metadata['envoy-gateway']['resources'][0]['name'])%

Access Log Types

By default, Access Log settings would apply to:

All Routes
If traffic is not matched by any Route known to Envoy, the Listener would emit the access log instead

Users may wish to customize this behavior:

Emit Access Logs by all Listeners for all traffic with specific settings
Do not emit Route-oriented access logs when a route is not matched.

To achieve this, users can select if Access Log settings follow the default behavior or apply specifically to Routes or Listeners by specifying the setting’s type.

Note: When users define their own Access Log settings (with or without a type), the default Envoy Gateway file access log is no longer configured. It can be re-enabled explicitly by adding empty settings for the desired components.

In the following example:

Route Access logs would use the default Envoy Gateway format and sink
Listener Access logs are customized to report transport-level failures and connection attributes

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: eg
spec:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller
  parametersRef:
    group: gateway.envoyproxy.io
    kind: EnvoyProxy
    name: otel-access-logging
    namespace: envoy-gateway-system
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: otel-access-logging
  namespace: envoy-gateway-system
spec:
  telemetry:
    accessLog:
      settings:
        - type: Route # re-enable default access log for route
        - type: Listener # configure specific access log for listeners
          format:
            type: Text
            text: |
              [%START_TIME%] %DOWNSTREAM_REMOTE_ADDRESS% %RESPONSE_FLAGS% %BYTES_RECEIVED% %BYTES_SENT% %DOWNSTREAM_TRANSPORT_FAILURE_REASON%
          sinks:
            - type: OpenTelemetry
              openTelemetry:
                host: otel-collector.monitoring.svc.cluster.local
                port: 4317
                resources:
                  k8s.cluster.name: "cluster-1"
EOF

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Last modified August 11, 2026: feat: expose gRPC access log buffering on the ALS and OpenTelemetry sinks (9a893d1f)