Istio in Action

appendix B. Istio’s sidecar and its injection options

In this book and in the wider Istio community, we synecdochically refer to Istio’s sidecar as the service proxy or Envoy proxy. This is natural because the proxy does the heavy lifting for most of Istio’s features. Yet this is not a one-person show; for example, without supportive components, the proxy cannot place itself in the request path of traffic directed toward apps (shortly, we explain how it does that). There are many other examples where Envoy is helpless, such as getting its identity bootstrapped, certificate rotation, and so on.

The sidecar has these components:

• The Istio agent, often referred to as the pilot agent, has important functions such as starting the Envoy proxy within ...