Service Splitter

v1.8.4+: On Kubernetes, the ServiceSplitter custom resource is supported in Consul versions 1.8.4+.
v1.6.0+: On other platforms, this config entry is supported in Consul versions 1.6.0+.

The service-splitter config entry kind (ServiceSplitter on Kubernetes) controls how to split incoming Connect requests across different subsets of a single service (like during staged canary rollouts), or perhaps across different services (like during a v2 rewrite or other type of codebase migration).

If no splitter config is defined for a service it is assumed 100% of traffic flows to a service with the same name and discovery continues on to the resolution stage.

Interaction with other Config Entries

Service splitter config entries are a component of L7 Traffic Management.
Service splitter config entries are restricted to only services that define their protocol as http-based via a corresponding service-defaults config entry or globally via proxy-defaults .
Any split destination that specifies a different Service field and omits the ServiceSubset field is eligible for further splitting should a splitter be configured for that other service, otherwise resolution proceeds according to any configured service-resolver.

Sample Config Entries

Two subsets of same service

Split traffic between two subsets of the same service:

Kind = "service-splitter"
Name = "web"
Splits = [
  {
    Weight        = 90
    ServiceSubset = "v1"
  },
  {
    Weight        = 10
    ServiceSubset = "v2"
  },
]

Split traffic between two subsets of the same service:

apiVersion: consul.hashicorp.com/v1alpha1
kind: ServiceSplitter
metadata:
  name: web
spec:
  splits:
    - weight: 90
      serviceSubset: v1
    - weight: 10
      serviceSubset: v2

Two different services

Split traffic between two services:

Kind = "service-splitter"
Name = "web"
Splits = [
  {
    Weight  = 50
    # will default to service with same name as config entry ("web")
  },
  {
    Weight  = 10
    Service = "web-rewrite"
  },
]

Split traffic between two services:

apiVersion: consul.hashicorp.com/v1alpha1
kind: ServiceSplitter
metadata:
  name: web
spec:
  splits:
    - weight: 50
      # will default to service with same name as config entry ("web")
    - weight: 10
      service: web-rewrite

Available Fields

Kind - Must be set to service-splitter
Name (string: <required>) - Set to the name of the service being configured.
Namespace (string: "default")Enterprise - Specifies the namespace the config entry will apply to.
Meta (map<string|string>: nil) - Specifies arbitrary KV metadata pairs. Added in Consul 1.8.4.
Splits (array<ServiceSplit>) - Defines how much traffic to send to which set of service instances during a traffic split. The sum of weights across all splits must add up to 100.
- weight (float32: 0) - A value between 0 and 100 reflecting what portion of traffic should be directed to this split. The smallest representable eight is 1/10000 or .01%
- Service (string: "") - The service to resolve instead of the default.
- ServiceSubset (string: "") - A named subset of the given service to resolve instead of one defined as that service's DefaultSubset. If empty the default subset is used.
- Namespace (string: "")Enterprise - The namespace to resolve the service from instead of the current namespace. If empty the current namespace is assumed.

apiVersion - Must be set to consul.hashicorp.com/v1alpha1
kind - Must be set to ServiceSplitter
metadata
- name - Set to the name of the service being configured.
- namespace - If running Consul Open Source, the namespace is ignored (see Kubernetes Namespaces in Consul OSS). If running Consul Enterprise see Kubernetes Namespaces in Consul Enterprise for more details.
spec
- splits (array<ServiceSplit>) - Defines how much traffic to send to which set of service instances during a traffic split. The sum of weights across all splits must add up to 100.
  - weight (float32: 0) - A value between 0 and 100 reflecting what portion of traffic should be directed to this split. The smallest representable eight is 1/10000 or .01%
  - service (string: "") - The service to resolve instead of the default.
  - serviceSubset (string: "") - A named subset of the given service to resolve instead of one defined as that service's defaultSubset. If empty the default subset is used.
  - namespace (string: "")Enterprise - The namespace to resolve the service from instead of the current namespace. If empty the current namespace is assumed.

ACLs

Configuration entries may be protected by ACLs.

Reading a service-splitter config entry requires service:read on the resource.

Creating, updating, or deleting a service-splitter config entry requires service:write on the resource and service:read on any other service referenced by name in these fields:

Splits[].Service