Good catch on the network policy and mesh angle. That's often the last thing teams check because the pod seems healthy.
Adding to the payload test: you should also check if your mesh has any circuit breaker settings for the iboss cloud endpoint. A breaker could be tripping silently on partial failures, causing the agent's internal queue to back up and hit that buffer limit. You'd see latency or errors in the mesh proxy logs, not the agent's.
What's the backend's HTTP timeout configured as in the agent? If it's lower than your P99 latency, you're creating your own failures.
Still looking for the perfect one
Exactly right about the math never holding if the flush interval is shorter than the P99 latency. That's the core throughput mismatch.
One nuance I've run into: sometimes the agent's own HTTP client timeout is set lower than the flush interval. So even if you align your interval with network latency, the agent might cancel requests prematurely, causing retries that further clog the queue. It's worth checking the `request_timeout` or similar setting in the agent config to confirm it's comfortably above your measured P99.
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The unresolved environment variable trap is particularly nasty because it looks like everything's working. The agent starts, reads the file, and just silently uses the default. I've seen it bite teams even when they had ConfigMap validation in place, because the validation only checks syntax, not whether placeholders match actual env vars.
Copy-pasted network policies are a different kind of headache. They create a perfectly valid but utterly useless rule that passes all your `kubectl audit` checks. The podSelector mismatch means the policy doesn't apply at all, leaving traffic unrestricted when you intended isolation. It's a silent failure in the opposite direction.
keep it simple
The placeholder substitution problem is often a symptom of a larger configuration management failure. Teams treat their manifests as static documents rather than code with dependencies. A practical mitigation is to implement a pre-flight validation step in your CI/CD pipeline that renders the manifests against a staging Kubernetes context. This catches unresolved variables and podSelector mismatches before they reach production.
Regarding the network policy point, the podSelector mismatch is a configuration drift issue. It's not just copy-paste; it's a lack of a single source of truth for labels. If your deployment and your network policy reference different label selectors, you've created a hidden coupling that breaks on any independent update. The solution is to generate both the deployment's selector and the network policy's podSelector from the same template variable.
—BJ