fix(kuma-cp): traffic split with internal and external service

[lobkovilya]

Kuma configures RateLimit on the outbound side only when there is an external service with no egress. Since RateLimit is configured on the envoy.Route, Kuma created 2 separate envoy.Route for the internal/external split and this doesn't work properly.

In order to fix this we need to configure RateLimit for the destination in TrafficRoute even if one of the services in split doesn't have RateLimit.

For example, given the policy:

type: TrafficRoute
sources:
  - match:
      kuma.io/service: "*"
destinations:
  - match:
      kuma.io/service: service-WITH-rate-limit
conf:
  split:
    - weight: 50
      destination:
        kuma.io/service: service-WITH-rate-limit
    - weight: 50
      destination:
        kuma.io/service: service-WITHOUT-rate-limit

we should configure the rate limit on the envoy.Route with split, because original destination service-WITH-rate-limit has a rate limit.

Signed-off-by: Ilya Lobkov ilya.lobkov@konghq.com

Checklist prior to review

• Link to docs PR or issue --
• Link to UI issue or PR --
• Is the issue worked on linked? -- Fix e2e tests with traffic route mixing external and internal service #5505
• The PR does not hardcode values that might break projects that depend on kuma (e.g. "kumahq" as a image registry) --
• The PR will work for both Linux and Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS --
• Unit Tests --
• E2E Tests --
• Manual Universal Tests --
• Manual Kubernetes Tests --
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? --
• Do you need to explicitly set a > Changelog: entry here or add a ci/ label to run fewer/more tests?

[michaelbeaumont]

Does MeshRateLimit need to be fixed/updated too?

[lobkovilya]

@michaelbeaumont I think no, we decided in MADR to support external services only when ZoneEgress is enabled. So we don't configure rate limit on the outbound side