PII-Shield sidecar strips sensitive data from Kubernetes logs before Fluentd reads them

A new approach to protecting personally identifiable information in Kubernetes logging pipelines uses a lightweight Go sidecar called PII-Shield, placed before Fluentd or Fluent Bit ever processes log data. Instead of relying on fragile regex filters embedded in Fluentd's record_transformer or Fluent Bit's Lua scripts, the sidecar intercepts raw application logs written to a shared ephemeral volume and scrubs sensitive fields using entropy-based detection. Masked values are replaced with traceable tokens like [HIDDEN:a1b2c3], preserving correlation across log lines without exposing actual secrets. The cleaned logs are then emitted to stdout, where the existing DaemonSet-based log collectors pick them up with no configuration changes needed. This design eliminates per-line interpreter overhead from Ruby or Lua processing and removes the risk of new secret formats silently bypassing unupdated regex patterns.