Proxy Access Logs

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

Prerequisites

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

Envoy Gateway provides an add-ons Helm Chart, which includes all the needing components for observability. By default, the OpenTelemetry Collector is disabled.

Install the add-ons Helm Chart:

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.

kubectl apply -f https://raw.githubusercontent.com/envoyproxy/gateway/main/examples/kubernetes/envoy-als.yaml -n monitoring

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: envoy-als
                    namespace: monitoring
                    port: 8080
                type: HTTP
EOF

Verify logs from envoy-als:

curl -s "http://$(kubectl get svc envoy-als -n monitoring -o jsonpath='{.status.loadBalancer.ingress[0].ip}'):19001/metrics" | grep log_count

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'

Additional 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 such as: %METADATA(ROUTE:envoy-gateway:resources)% to their access log format.

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 October 17, 2024: api: direct response (#4334) (5375cf0)