istio virtual host and destination rule basics

In Istio we need virtual service and destination rule to route our traffic to the right service. 
What is the bare minimum correct configuration that is needed to do this? 

1. VirtualService.spec.hosts = DestinationRule.spec.host - this host must be exactly the same, for example if there is a host for "server-a.example.com" in virtual service, then the destination rule host must have "server-a.example.com".


2. Subset if exist - needs to exist in both virtual service and destination rule. 


A minimal configuration would look like this:- 


apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: reviews-destination
spec:
  host: reviews   # MUST match VirtualService hosts
  subsets:
    - name: v1
      labels:
        version: v1
---
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: reviews
spec:
  gateways:
    - shared-gateway.gateway-system.svc.cluster.local  # MUST match Gateway name and namespace
  hosts:
    - reviews       # MUST match DestinationRule host
  http:
    - route:
        - destination:
            host: reviews
            subset: v1    # MUST match DestinationRule subset






Comments

Post a Comment

Popular posts from this blog

gemini cli getting file not defined error

Image
 While trying to run gemini cli on my windows linux subsystem, i bump into this error here - "/Roaming/npm/node_modules/@google/gemini-cli/node_modules/undici/lib/web/webidl/index.js:512 webidl.is.File = webidl.util.MakeTypeAssertion(File)"  "ReferenceError: File is not defined" In Node.js, there’s no built-in File (until very recent Node 20+ with experimental WHATWG APIs). So, unless polyfilled, File is undefined, leading to the ReferenceError. And to resolve this, I had to upgrade to node 22 (might work for node 20) and then I was able to run it.
Read more

NodeJS: Error: spawn EINVAL in window for node version 20.20 and 18.20

Encounter this issue when running autorest (that uses nodejs).  I am using node version:  v18.20.2 After i revert to use node v18.12.0, then i was able to get my app to run without this error. Since i am working with Azure devops yaml, i was able to use the following to resolve my issue.  - task : NodeTool@0   inputs :     versionSource : 'spec'     versionSpec : '18.18.0'
Read more

vllm : Failed to infer device type

Trying to run vllm without gpu will typicaly lands you into this issue. To resolve this issue: we can use set these both. Setting one does not work for me. So i had to configure both settings below:- 1.  environment variable CUDA_VISIBLE_DEVICES = "" 2. in the command line, change to use device cpu and remove  tensor-parallel-size. For example, python3 -m vllm.entrypoints.openai.api_server --port 8080 --model deepseek-ai/DeepSeek-R1 --device cpu --trust-remote-code --max-model-len 4096" References https://docs.vllm.ai/en/latest/getting_started/troubleshooting.html#failed-to-infer-device-type
Read more