Kuma Star

Mesh HTTP Route

This policy uses new policy matching algorithm. It’s recommended to migrate from TrafficRoute. See “Interactions with TrafficRoute” section for more information.

The MeshHTTPRoute policy allows altering and redirecting HTTP requests depending on where the request is coming from and where it’s going to.

TargetRef support matrix

targetRef Allowed kinds
targetRef.kind Mesh, MeshSubset
to[].targetRef.kind MeshService

If you don’t understand this table you should read matching docs.

Configuration

Unlike others outbound policies MeshHTTPRoute doesn’t contain default directly in the to array. The default section is nested inside rules, so the policy structure looks like this:

spec:
  to:
    - targetRef: {...}
      rules:
        - matches: [...] # various ways to match an HTTP request (path, method, query)
          default: # configuration applied for the matched HTTP request
            filters: [...]
            backendRefs: [...]

Remember to tag your Service ports with appProtocol: http to use them in a MeshHTTPRoute!

Gateways

In order to route HTTP traffic for a MeshGateway, you need to target the MeshGateway in spec.targetRef and set spec.to[].targetRef.kind: Mesh.

Interactions with MeshTCPRoute

MeshHTTPRoute takes priority over MeshTCPRoute when a proxy is targeted by both and the matching MeshTCPRoute is ignored.

Interactions with TrafficRoute

MeshHTTPRoute takes priority over TrafficRoute when a proxy is targeted by both policies.

All legacy policies like Retry, TrafficLog, Timeout etc. only match on routes defined by TrafficRoute. All new recommended policies like MeshRetry, MeshAccessLog, MeshTimeout etc. match on routes defined by MeshHTTPRoute and TrafficRoute.

If you don’t use legacy policies, it’s recommended to remove any existing TrafficRoute. Otherwise, it’s recommended to migrate to new policies and then removing TrafficRoute.

Examples

Traffic split

We can use MeshHTTPRoute to split an HTTP traffic between different MeshServices implementing A/B testing or canary deployments. If we want to split traffic between v1 and v2 versions of the same service, first we have to create MeshServices backend-v1 and backend-v2 that select backend application instances according to the version.

apiVersion: kuma.io/v1alpha1
kind: MeshHTTPRoute
metadata:
  name: http-split
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: MeshSubset
    tags:
      app: frontend
  to:
  - targetRef:
      kind: MeshService
      name: backend_kuma-demo_svc_3001
    rules:
    - matches:
      - path:
          type: PathPrefix
          value: "/"
      default:
        backendRefs:
        - kind: MeshServiceSubset
          name: backend_kuma-demo_svc_3001
          weight: 90
          tags:
            version: v1
        - kind: MeshServiceSubset
          name: backend_kuma-demo_svc_3001
          weight: 10
          tags:
            version: v2

apiVersion: kuma.io/v1alpha1
kind: MeshHTTPRoute
metadata:
  name: http-split
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: MeshSubset
    tags:
      app: frontend
  to:
  - targetRef:
      kind: MeshService
      name: backend
      namespace: kuma-demo
      sectionName: http
    rules:
    - matches:
      - path:
          type: PathPrefix
          value: "/"
      default:
        backendRefs:
        - kind: MeshService
          name: backend-v1
          namespace: kuma-demo
          port: 3001
          weight: 90
        - kind: MeshService
          name: backend-v2
          namespace: kuma-demo
          port: 3001
          weight: 10

Traffic modifications

We can use MeshHTTPRoute to modify outgoing requests, by setting new path or changing request and response headers.

Here is an example of a MeshHTTPRoute that adds x-custom-header with value xyz when frontend tries to consume backend.

apiVersion: kuma.io/v1alpha1
kind: MeshHTTPRoute
metadata:
  name: http-route-1
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: MeshSubset
    tags:
      app: frontend
  to:
  - targetRef:
      kind: MeshService
      name: backend_kuma-demo_svc_3001
    rules:
    - matches:
      - path:
          type: Exact
          value: "/"
      default:
        filters:
        - type: RequestHeaderModifier
          requestHeaderModifier:
            set:
            - name: x-custom-header
              value: xyz

apiVersion: kuma.io/v1alpha1
kind: MeshHTTPRoute
metadata:
  name: http-route-1
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: MeshSubset
    tags:
      app: frontend
  to:
  - targetRef:
      kind: MeshService
      name: backend
      namespace: kuma-demo
      sectionName: http
    rules:
    - matches:
      - path:
          type: Exact
          value: "/"
      default:
        filters:
        - type: RequestHeaderModifier
          requestHeaderModifier:
            set:
            - name: x-custom-header
              value: xyz

Traffic mirror

MeshHTTPRoute can mirror a fraction of requests to another service. This can be useful when testing a new version of the app with the production payload without interrupting real users.

apiVersion: kuma.io/v1alpha1
kind: MeshHTTPRoute
metadata:
  name: http-route-1
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: MeshSubset
    tags:
      app: frontend
  to:
  - targetRef:
      kind: MeshService
      name: backend_kuma-demo_svc_3001
    rules:
    - matches:
      - headers:
        - type: Exact
          name: mirror-this-request
          value: 'true'
      default:
        filters:
        - type: RequestMirror
          requestMirror:
            percentage: 30
            backendRef:
              kind: MeshServiceSubset
              name: backend_kuma-demo_svc_3001
              tags:
                version: v1-experimental
        backendRefs:
        - kind: MeshService
          name: backend_kuma-demo_svc_3001

apiVersion: kuma.io/v1alpha1
kind: MeshHTTPRoute
metadata:
  name: http-route-1
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: MeshSubset
    tags:
      app: frontend
  to:
  - targetRef:
      kind: MeshService
      name: backend
      namespace: kuma-demo
      sectionName: http
    rules:
    - matches:
      - headers:
        - type: Exact
          name: mirror-this-request
          value: 'true'
      default:
        filters:
        - type: RequestMirror
          requestMirror:
            percentage: 30
            backendRef:
              kind: MeshService
              name: backend-v1-experimental
              namespace: kuma-demo
              port: 3001
        backendRefs:
        - kind: MeshService
          name: backend
          namespace: kuma-demo
          port: 3001

Merging

When several MeshHTTPRoute policies target the same data plane proxy they’re merged. Similar to the new policies the merging order is determined by the top level targetRef. The difference is in spec.to[].rules. Kuma treats rules as a key-value map where matches is a key and default is a value. For example MeshHTTPRoute policies:

# MeshHTTPRoute-1
rules:
  - matches: # key-1
      - path:
          type: Exact
          name: /orders
        method: GET
    default: CONF_1 # value
  - matches: # key-2
      - path:
          type: Exact
          name: /payments
        method: POST
    default: CONF_2 # value
---
# MeshHTTPRoute-2
rules:
  - matches: # key-3
      - path:
          type: Exact
          name: /orders
        method: GET
    default: CONF_3 # value
  - matches: # key-4
      - path:
          type: Exact
          name: /payments
        method: POST
    default: CONF_4 # value

merged in the following list of rules:

rules:
  - matches:
      - path:
          type: Exact
          name: /orders
        method: GET
    default: merge(CONF_1, CONF_3) # because 'key-1' == 'key-3'
  - matches:
      - path:
          type: Exact
          name: /payments
        method: POST
    default: merge(CONF_2, CONF_4) # because 'key-2' == 'key-4'

All policy options

Matches

  • path - (optional) - HTTP path to match the request on
    • type - one of Exact, PathPrefix, RegularExpression
    • value - actual value that’s going to be matched depending on the type
  • method - (optional) - HTTP2 method, available values are CONNECT, DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT, TRACE
  • queryParams - (optional) - list of HTTP URL query parameters. Multiple matches are combined together such that all listed matches must succeed
    • type - one of Exact or RegularExpression
    • name - name of the query parameter
    • value - actual value that’s going to be matched depending on the type

Default conf

  • filters - (optional) - a list of modifications applied to the matched request
    • type - available values are RequestHeaderModifier, ResponseHeaderModifier, RequestRedirect, URLRewrite.
    • requestHeaderModifier - HeaderModifier, must be set if the type is RequestHeaderModifier.
    • responseHeaderModifier - HeaderModifier, must be set if the type is ResponseHeaderModifier.
    • requestRedirect - must be set if the type is RequestRedirect
      • scheme - one of http or http2
      • hostname - is the fully qualified domain name of a network host. This matches the RFC 1123 definition of a hostname with 1 notable exception that numeric IP addresses are not allowed.
      • port - is the port to be used in the value of the Location header in the response. When empty, port (if specified) of the request is used.
      • statusCode - is the HTTP status code to be used in response. Available values are 301, 302, 303, 307, 308.
    • urlRewrite - must be set if the type is URLRewrite
      • hostname - (optional) - is the fully qualified domain name of a network host. This matches the RFC 1123 definition of a hostname with 1 notable exception that numeric IP addresses are not allowed.
      • path - (optional)
        • type - one of ReplaceFullPath, ReplacePrefixMatch
        • replaceFullPath - must be set if the type is ReplaceFullPath
        • replacePrefixMatch - must be set if the type is ReplacePrefixMatch
    • requestMirror - must be set if the type is RequestMirror
      • percentage - percentage of requests to mirror. If not specified, all requests to the target cluster will be mirrored.
      • backendRef - BackendRef, destination to mirror request to
  • backendRefs - BackendRef (optional), list of destinations to redirect requests to

Header modification

  • set - (optional) - list of headers to set. Overrides value if the header exists.
    • name - header’s name
    • value - header’s value
  • add - (optional) - list of headers to add. Appends value if the header exists.
    • name - header’s name
    • value - header’s value
  • remove - (optional) - list of headers’ names to remove

Backends

  • kind - one of MeshService, MeshServiceSubset, MeshExtenalService
  • name - service name
  • tags - service tags, must be specified if the kind is MeshServiceSubset
  • weight - when a request matches the route, the choice of an upstream cluster is determined by its weight. Total weight is a sum of all weights in backendRefs list.