Traffic management with Istio in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Istio VirtualService configuration?

Given this VirtualService YAML snippet, what will be the percentage of traffic routed to version v2 of the service?

Kubernetes

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
      weight: 80
    - destination:
        host: reviews
        subset: v2
      weight: 20

A 20%

B 80%

C 50%

D 0%

💡 Hint

Look at the weights assigned to each subset in the route section.

The VirtualService routes 80% of traffic to subset v1 and 20% to subset v2, so v2 gets 20%.

🧠 Conceptual

intermediate

Which Istio resource controls the routing rules for traffic splitting?

In Istio, which resource is responsible for defining how traffic is split between different versions of a service?

A DestinationRule

B Gateway

C ServiceEntry

D VirtualService

💡 Hint

This resource defines HTTP routing rules and traffic distribution.

VirtualService defines routing rules including traffic splitting between subsets.

❓ Troubleshoot

advanced

Why does traffic not split as expected despite correct VirtualService weights?

You configured a VirtualService to split traffic 50-50 between v1 and v2 subsets. However, all traffic goes to v1. What is the most likely cause?

A DestinationRule does not define subsets v1 and v2

B Gateway resource is missing

C ServiceEntry is blocking traffic to v2

D Sidecar proxy is not installed

💡 Hint

Check if subsets used in VirtualService are defined elsewhere.

If subsets are not defined in DestinationRule, traffic routing to those subsets fails, defaulting to one version.

🔀 Workflow

advanced

Order the steps to implement canary deployment with Istio traffic shifting

Arrange these steps in the correct order to perform a canary deployment using Istio traffic management.

A 1,3,2,4

B 1,2,3,4

C 2,1,3,4

D 2,3,1,4

💡 Hint

Think about deploying first, then defining subsets, then routing, then shifting traffic.

First deploy v2, then define subsets in DestinationRule, then create VirtualService for routing, then increase traffic gradually.

✅ Best Practice

expert

What is the best practice to avoid downtime during Istio traffic shifting?

When shifting traffic between service versions in Istio, what practice helps avoid downtime and errors?

A Disable sidecar proxies during deployment

B Delete old version before shifting traffic

C Use gradual traffic shifting with monitoring and rollback

D Shift 100% traffic immediately to new version

💡 Hint

Think about minimizing risk and detecting issues early.

Gradual traffic shifting with monitoring allows detecting problems early and rolling back if needed, avoiding downtime.