What’s New in Istio 1.3? Key Features and Improvements Unveiled

Istio is an open‑source service‑mesh framework jointly developed by Google, IBM and Lyft, designed to address service discovery, connection, management, monitoring and security for large numbers of microservices. It operates transparently, requiring no changes to application code.

Version 1.3 was released more than two months after 1.2, bringing several notable changes.

Automatic protocol detection : In previous releases, using Istio’s routing required Service ports to follow a special naming convention. Starting with 1.3, Istio automatically detects outbound traffic protocols as HTTP or TCP even without the naming rule. Automatic detection for inbound traffic is not yet supported.

No‑Mixer telemetry (experimental) : Most security policies (e.g., RBAC) and many telemetry functions have been moved into Envoy. The Istio proxy now exposes HTTP metrics directly to Prometheus without the istio‑telemetry service. A new “no‑Mixer HTTP telemetry” feature is available, with TCP telemetry support planned for future releases.

Elimination of required containerPort : Earlier versions required each Pod to declare a containerPort, and undeclared ports bypassed the Istio proxy. Version 1.3 allows handling of all inbound traffic on any workload port without declaring containerPort, and fixes a previous iptables loop issue.

Fully custom Envoy configuration : Advanced users can now leverage Envoy features not covered by the Istio networking API. The EnvoyFilter API has been enhanced to let users customize:

LDS‑provided HTTP/TCP listeners and filter chains;

RDS‑provided HTTP route configurations;

CDS‑provided Cluster configurations.

Other enhancements include:

New debugging capabilities in istioctl;

Region‑aware load balancing moved to the default branch;

Improved support for headless services when mutual TLS is enabled;

Additional control‑plane metrics, sidecar‑injector metrics, and new Grafana dashboards for Citadel and Pilot;

Updated deployment‑model documentation and a reorganized operations guide with a dedicated troubleshooting chapter.

For full details, see the official “Announcing Istio 1.3” announcement.