Code RoomCA rotation trust bundle incomplete
HardPrep Room Coding #2828

CA rotation trust bundle incomplete

On-callReliability & on-callSenior–Staff~40 min

Your mesh rotates per-sidecar mTLS certs via the control plane's secret-discovery service (SDS). Roughly every hour you get a ~20-second burst of mTLS handshake failures ('tls: bad certificate' / 'certificate signed by unknown authority') between certain service pairs, then it self-heals. Dashboards: the bursts align exactly with cert-rotation windows; the control plane is healthy; failures cluster on the newest pods. The root CA was rotated yesterday (a new signing key added to the trust bundle) as part of a planned CA migration. How do you triage and mitigate?

What a strong answer looks like

Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.

0:00 of about 40 min
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