When communicating over the network, many things can go wrong, as we’ve demonstrated throughout this book. A major reason why Istio exists is to help shine a light on network communication when things go wrong and put in place remediation capabilities like timeouts, retries, and circuit breaking so that applications can automatically respond to network issues. The service proxy gives us a very detailed view of what’s happening on the network, but what happens when the proxy itself behaves unexpectedly?
- istiod, which ensures that the data plane is synchronized to the desired state
- The ingress gateway that admits traffic into the cluster
- The service proxy that provides access control and handles traffic from downstream to the local application
- The application itself, which serves the request and may request another service that continues the chain to another upstream service, and so on