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README
Istio
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Istio is an open source service mesh that layers transparently onto existing distributed applications. Istio’s powerful features provide a uniform and more efficient way to secure, connect, and monitor services. Istio is the path to load balancing, service-to-service authentication, and monitoring – with few or no service code changes.
- For in-depth information about how to use Istio, visit istio.io
- To ask questions and get assistance from our community, visit GitHub Discussions
- To learn how to participate in our overall community, visit our community page
In this README:
- Introduction
- Repositories
- Issue management
In addition, here are some other documents you may wish to read:
- Istio Community - describes how to get involved and contribute to the Istio project
- Istio Developer's Guide - explains how to set up and use an Istio development environment
- Project Conventions - describes the conventions we use within the code base
- Creating Fast and Lean Code - performance-oriented advice and guidelines for the code base
You'll find many other useful documents on our Wiki.
Introduction
Istio is an open platform for providing a uniform way to integrate
microservices, manage traffic flow across microservices, enforce policies
and aggregate telemetry data. Istio's control plane provides an abstraction
layer over the underlying cluster management platform, such as Kubernetes.
Istio is composed of these components:
- Envoy - Sidecar proxies per microservice to handle ingress/egress traffic
between services in the cluster and from a service to external
services. The proxies form a _secure microservice mesh_ providing a rich
set of functions like discovery, rich layer-7 routing, circuit breakers,
policy enforcement and telemetry recording/reporting
functions.
Note: The service mesh is not an overlay network. It
simplifies and enhances how microservices in an application talk to each
other over the network provided by the underlying platform.
Ztunnel - A lightweight data plane proxy written in Rust,
used in Ambient mesh mode to provide secure connectivity and observability for workloads without sidecar proxies.
- Istiod - The Istio control plane. It provides service discovery, configuration and certificate management.
Repositories
The Istio project is divided across a few GitHub repositories:
- istio/api. This repository defines
component-level APIs and common configuration formats for the Istio platform.
- istio/community. This repository contains
information on the Istio community, including the various documents that govern
the Istio open source project.
- istio/istio. This is the main code repository. It hosts Istio's
core components, install artifacts, and sample programs. It includes:
- istioctl. This directory contains code for the
_istioctl_ command line utility.
- pilot. This directory
contains platform-specific code to populateTop issues
#1430UDP support101 comments · 2017-11-03#22997Merging of split VirtualServices using the mesh gateway (sidecars)76 comments · 2020-04-16#252180DPE (Downstream Protocol Error) caused by HTTP2 Filter53 comments · 2020-07-05#43105Customizing SPIFFE ID format if using an external SPIFFE-compliant SDS should be supported51 comments · 2023-02-02#27893Support Windows in Istio Data Plane50 comments · 2020-10-12#58514503 Spikes During Pod Rollout - Pod Terminates Before Ztunnel Removes Workload48 comments · 2025-12-06#42339SPIRE integration with Ambient44 comments · 2022-12-07#48084Locality based load balancing is dependent on outlier detection41 comments · 2023-11-29
Discussions
#62470Port 15091 (secure metrics) not exempt from ISTIO_INBOUND redirect — mTLS scrape fails1 comments · 2026-10-27#62462v1.29.9 announcement confusion1 comments · 2026-10-27#62223Next Istio Security Release for 1.29, 1.30 and 1.31 Istio Releases.0 comments · 2026-10-13#62090How to handle unpredictable XDS config size pushed to sidecars?3 comments · 2026-10-07#62054Roadmap for ztunnel upgrade strategies0 comments · 2026-10-05#61978Unable to verify Istio 1.31.1 signatures1 comments · 2026-09-29#61963Regarding Annotations/Label2 comments · 2026-09-28#61893istio 404 error for tls passthrough1 comments · 2026-09-24
Latest release
Istio 1.31.4 1.31.4 2026-11-06Release Notes