You created a NetworkPolicy to allow traffic only from Pods with label app=frontend to Pods with label app=backend. However, backend Pods are still accessible from other Pods. What is the likely cause?
AThe NetworkPolicy is applied in the wrong namespace.
BThe NetworkPolicy is missing a podSelector, so it applies to all Pods.
CThe backend Pods do not have the label <code>app=backend</code>.
DThe NetworkPolicy does not specify any ingress rules, so all traffic is allowed.
Step-by-Step Solution
Solution:
Step 1: Verify label matching on backend Pods
If backend Pods lack the label app=backend, the NetworkPolicy does not select them, so it does not restrict their traffic.
Step 2: Check other possible causes
NetworkPolicy without ingress rules denies all traffic, missing podSelector applies to all Pods, wrong namespace means policy doesn't affect target Pods.
Final Answer:
The backend Pods do not have the label app=backend. -> Option C
Quick Check:
Labels must match for NetworkPolicy to apply [OK]
Quick Trick:Check Pod labels match NetworkPolicy selectors [OK]
Common Mistakes:
Assuming NetworkPolicy applies without matching labels
Ignoring namespace differences
Thinking missing ingress means allow all
Master "Networking" in Kubernetes
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