Istio Sidecar Bootstrap Override Annotation¶

The Istio Sidecar Bootstrap Override Annotation is a mechanism used to inject custom Envoy proxy configurations into a Kubernetes Pod managed by Istio.^[400-devops-07-monitoring-and-observability-k8s-istio-samples-custom-bootstrap-readme.md]

Implementation¶

To apply a custom bootstrap configuration, a ConfigMap resource containing the desired configuration must first be created.^[400-devops-07-monitoring-and-observability-k8s-istio-samples-custom-bootstrap-readme.md] This configuration is then attached to a specific application Pod using the annotation sidecar.istio.io/bootstrapOverride, where the annotation value corresponds to the name of the ConfigMap.^[400-devops-07-monitoring-and-observability-k8s-istio-samples-custom-bootstrap-readme.md]

Configuration Behavior¶

The custom configuration is passed to the Envoy proxy via the --config-yaml flag.^[400-devops-07-monitoring-and-observability-k8s-istio-samples-custom-bootstrap-readme.md] This process merges the provided configuration with the default bootstrap configuration: singular values replace the default values, while repeated values are appended to the defaults.^[400-devops-07-monitoring-and-observability-k8s-istio-samples-custom-bootstrap-readme.md]

Verification¶

To verify which bootstrap configuration is currently active for a specific Pod, the following istioctl command can be used:^[400-devops-07-monitoring-and-observability-k8s-istio-samples-custom-bootstrap-readme.md]

[istioctl](<./istioctl.md>) proxy-config bootstrap <POD-NAME>

Sources¶

^[400-devops-07-monitoring-and-observability-k8s-istio-samples-custom-bootstrap-readme.md]