MeshAccessLog (beta)

With the MeshAccessLog policy you can easily set up access logs on every data plane proxy in a mesh.

This policy uses a new policy matching algorithm and is in beta state. It should not be combined with TrafficLog.

This guide assumes you have already configured your observability tools to work with Kuma. If you haven’t, see the observability docs.

targetRef support matrix

targetRef.kind top level to from
Mesh
MeshSubset
MeshService
MeshServiceSubset

To learn more about the information in this table, see the matching docs.

Configuration

Format

Kuma gives you full control over the format of the access logs.

The shape of a single log record is defined by a template string that uses command operators to extract and format data about a TCP connection or an HTTP request.

For example:

%START_TIME% %KUMA_SOURCE_SERVICE% => %KUMA_DESTINATION_SERVICE% %DURATION%

%START_TIME% and %KUMA_SOURCE_SERVICE% are examples of available command operators.

All command operators defined by Envoy are supported, along with additional command operators defined by Kuma:

Command Operator Description
%KUMA_MESH% Name of the mesh in which traffic is flowing.
%KUMA_SOURCE_SERVICE% Name of a service that is the source of traffic.
%KUMA_DESTINATION_SERVICE% Name of a service that is the destination of traffic.
%KUMA_SOURCE_ADDRESS_WITHOUT_PORT% Address of a Dataplane that is the source of traffic.
%KUMA_TRAFFIC_DIRECTION% Direction of the traffic, INBOUND, OUTBOUND, or UNSPECIFIED.

All additional access log command operators are valid to use with both TCP and HTTP traffic.

If a command operator is specific to HTTP traffic, such as %REQ(X?Y):Z% or %RESP(X?Y):Z%, it will be replaced by a symbol “-” in case of TCP traffic.

Internally, Kuma determines traffic protocol based on the value of kuma.io/protocol tag on the inbound interface of a destination Dataplane.

There are two types of format, plain and json.

Plain accepts a string with command operators and produces a string output.

JSON accepts a list of key-value pairs that produces a valid JSON object.

It is up to the user to decide which format type to use. Some system will automatically parse JSON logs and allow you to filter and query based on available keys.

Plain

The default format string for TCP traffic is:

[%START_TIME%] %RESPONSE_FLAGS% %KUMA_MESH% %KUMA_SOURCE_ADDRESS_WITHOUT_PORT%(%KUMA_SOURCE_SERVICE%)->%UPSTREAM_HOST%(%KUMA_DESTINATION_SERVICE%) took %DURATION%ms, sent %BYTES_SENT% bytes, received: %BYTES_RECEIVED% bytes

The default format string for HTTP traffic is:

[%START_TIME%] %KUMA_MESH% "%REQ(:METHOD)% %REQ(X-ENVOY-ORIGINAL-PATH?:PATH)% %PROTOCOL%" %RESPONSE_CODE% %RESPONSE_FLAGS% %BYTES_RECEIVED% %BYTES_SENT% %DURATION% %RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)% "%REQ(X-FORWARDED-FOR)%" "%REQ(USER-AGENT)%" "%REQ(X-REQUEST-ID)%" "%REQ(:AUTHORITY)%" "%KUMA_SOURCE_SERVICE%" "%KUMA_DESTINATION_SERVICE%" "%KUMA_SOURCE_ADDRESS_WITHOUT_PORT%" "%UPSTREAM_HOST%"

Example configuration:

format:
  plain: '[%START_TIME%] %BYTES_RECEIVED%'

Example output:

[2016-04-15T20:17:00.310Z] 154

JSON

Example configuration:

format:
  json:
    - key: "start_time"
      value: "%START_TIME%"
    - key: "bytes_received"
      value: "%BYTES_RECEIVED%"

Example output:

{
  "start_time": "2016-04-15T20:17:00.310Z",
  "bytes_received": "154"
}
TCP configuration with default fields:
format:
  json:
    - key: "start_time"
      value: "%START_TIME%"
    - key: "response_flags"
      value: "%RESPONSE_FLAGS%"
    - key: "kuma_mesh"
      value: "%KUMA_MESH%"
    - key: "kuma_source_address_without_port"
      value: "%KUMA_SOURCE_ADDRESS_WITHOUT_PORT%"
    - key: "kuma_source_service"
      value: "%KUMA_SOURCE_SERVICE%"
    - key: "upstream_host"
      value: "%UPSTREAM_HOST%"
    - key: "kuma_destination_service"
      value: "%KUMA_DESTINATION_SERVICE%"
    - key: "duration_ms"
      value: "%DURATION%"
    - key: "bytes_sent"
      value: "%BYTES_SENT%"
    - key: "bytes_received"
      value: "%BYTES_RECEIVED%"
HTTP configuration with default fields:
format:
  json:
    - key: "start_time"
      value: "%START_TIME%"
    - key: "kuma_mesh"
      value: "%KUMA_MESH%"
    - key: 'method'
      value: '"%REQ(:METHOD)%'
    - key: "path"
      value: "%REQ(X-ENVOY-ORIGINAL-PATH?:PATH)%"
    - key: 'protocol'
      value: '%PROTOCOL%'
    - key: "response_code"
      value: "%RESPONSE_CODE%"
    - key: "response_flags"
      value: "%RESPONSE_FLAGS%"
    - key: "bytes_received"
      value: "%BYTES_RECEIVED%"
    - key: "bytes_sent"
      value: "%BYTES_SENT%"
    - key: "duration_ms"
      value: "%DURATION%"
    - key: "upstream_service_time"
      value: "%RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)%"
    - key: 'x_forwarded_for'
      value: '"%REQ(X-FORWARDED-FOR)%"'
    - key: 'user_agent'
      value: '"%REQ(USER-AGENT)%"'
    - key: 'request_id'
      value: '"%REQ(X-REQUEST-ID)%"'
    - key: 'authority'
      value: '"%REQ(:AUTHORITY)%"'
    - key: "kuma_source_service"
      value: "%KUMA_SOURCE_SERVICE%"
    - key: "kuma_destination_service"
      value: "%KUMA_DESTINATION_SERVICE%"
    - key: "kuma_source_address_without_port"
      value: "%KUMA_SOURCE_ADDRESS_WITHOUT_PORT%"
    - key: "upstream_host"
      value: "%UPSTREAM_HOST%"

Backends

A backend determines where the logs end up.

TCP

A TCP backend streams logs to a server via TCP protocol. You can configure a TCP backend with an address:

backends:
  - tcp:
      address: 127.0.0.1:5000

File

A file backend streams logs to a text file. You can configure a file backend with a path:

backends:
  - file:
      path: /tmp/access.log

Examples

Log outgoing traffic from specific frontend version to a backend service

apiVersion: kuma.io/v1alpha1
kind: MeshAccessLog
metadata:
  name: default
  namespace: kuma-system
  labels:
    kuma.io/mesh: default # optional, defaults to `default` if it isn't configured
spec:
  targetRef:
    kind: MeshService
    name: frontend
    tags:
      version: canary
  to:
    - targetRef:
        kind: MeshService
        name: backend
      default:
        backends:
          - file:
              path: /tmp/access.log

Apply the configuration with kubectl apply -f [..].

Logging to multiple backends

This configuration logs to two backends: TCP and file.

apiVersion: kuma.io/v1alpha1
kind: MeshAccessLog
metadata:
  name: default
  namespace: kuma-system
  labels:
    kuma.io/mesh: default # optional, defaults to `default` if it isn't configured
spec:
  targetRef:
    kind: Mesh
  from:
    - targetRef:
        kind: Mesh
      default:
        backends:
          - file:
              address: 127.0.0.1:5000
              format:
                json:
                  - key: "start_time"
                    value: "%START_TIME%"
          - file:
              path: /tmp/access.log
              format:
                plain: '[%START_TIME%]'

Apply the configuration with kubectl apply -f [..].

Log all incoming and outgoing traffic

apiVersion: kuma.io/v1alpha1
kind: MeshAccessLog
metadata:
  name: default
  namespace: kuma-system
  labels:
    kuma.io/mesh: default # optional, defaults to `default` if it isn't configured
spec:
  targetRef:
    kind: Mesh
  from: # delete this section if you don't want to log incoming traffic
    - targetRef:
        kind: Mesh
      default:
        backends:
          - file:
              path: /tmp/access.log
  to: # delete this section if you don't want to log outgoing traffic
    - targetRef:
        kind: Mesh
      default:
        backends:
          - file:
              path: /tmp/access.log

Apply the configuration with kubectl apply -f [..].

Logging traffic going outside the Mesh

To target ExternalServices, use MeshService as the targetRef kind with name set to
the kuma.io/service value.

To target other non-mesh traffic, i.e. passthrough traffic, use Mesh as the targetRef kind. In this case, %KUMA_DESTINATION_SERVICE% is set to external.

Select a built-in gateway

You can select a built-in gateway using the kuma.io/service value. A current limitation is that traffic routed from a gateway to a service is logged by that gateway as having destination "*".

Last Updated: 11/4/2022, 19:20:08 PM