# Istio [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/1395/badge)](https://bestpractices.coreinfrastructure.org/projects/1395) [![Go Report Card](https://goreportcard.com/badge/github.com/istio/istio)](https://goreportcard.com/report/github.com/istio/istio) [![GoDoc](https://godoc.org/istio.io/istio?status.svg)](https://godoc.org/istio.io/istio) --- 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](https://istio.io) - To ask questions and get assistance from our community, visit [Github Discussions](https://github.com/istio/istio/discussions) - To learn how to participate in our overall community, visit [our community page](https://istio.io/about/community) In this README: - [Introduction](#introduction) - [Repositories](#repositories) - [Issue management](#issue-management) In addition, here are some other documents you may wish to read: - [Istio Community](https://github.com/istio/community#istio-community) - describes how to get involved and contribute to the Istio project - [Istio Developer's Guide](https://github.com/istio/istio/wiki/Preparing-for-Development) - explains how to set up and use an Istio development environment - [Project Conventions](https://github.com/istio/istio/wiki/Development-Conventions) - describes the conventions we use within the code base - [Creating Fast and Lean Code](https://github.com/istio/istio/wiki/Writing-Fast-and-Lean-Code) - performance-oriented advice and guidelines for the code base You'll find many other useful documents on our [Wiki](https://github.com/istio/istio/wiki). ## Introduction [Istio](https://istio.io/latest/docs/concepts/what-is-istio/) is an open platform for providing a uniform way to [integrate microservices](https://istio.io/latest/docs/examples/microservices-istio/), manage [traffic flow](https://istio.io/latest/docs/concepts/traffic-management/) 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. - **Istiod** - The Istio control plane. It provides service discovery, configuration and certificate management. It consists of the following sub-components: - **Pilot** - Responsible for configuring the proxies at runtime. - **Citadel** - Responsible for certificate issuance and rotation. - **Galley** - Responsible for validating, ingesting, aggregating, transforming and distributing config within Istio. - **Operator** - The component provides user friendly options to operate the Istio service mesh. ## Repositories The Istio project is divided across a few GitHub repositories: - [istio/api](https://github.com/istio/api). This repository defines component-level APIs and common configuration formats for the Istio platform. - [istio/community](https://github.com/istio/community). This repository contains information on the Istio community, including the various documents that govern the Istio open source project. - [istio/istio](README.md). This is the main code repository. It hosts Istio's core components, install artifacts, and sample programs. It includes: - [istioctl](istioctl/). This directory contains code for the [_istioctl_](https://istio.io/latest/docs/reference/commands/istioctl/) command line utility. - [operator](operator/). This directory contains code for the [Istio Operator](https://istio.io/latest/docs/setup/install/operator/). - [pilot](pilot/). This directory contains platform-specific code to populate the [abstract service model](https://istio.io/docs/concepts/traffic-management/#pilot), dynamically reconfigure the proxies when the application topology changes, as well as translate [routing rules](https://istio.io/latest/docs/reference/config/networking/) into proxy specific configuration. - [security](security/). This directory contains [security](https://istio.io/latest/docs/concepts/security/) related code, including Citadel (acting as Certificate Authority), citadel agent, etc. - [istio/proxy](https://github.com/istio/proxy). The Istio proxy contains extensions to the [Envoy proxy](https://github.com/envoyproxy/envoy) (in the form of Envoy filters) that support authentication, authorization, and telemetry collection. - [istio/ztunnel](https://github.com/istio/ztunnel). The repository contains the Rust implementation of the ztunnel component of Ambient mesh. ## Issue management We use GitHub to track all of our bugs and feature requests. Each issue we track has a variety of metadata: - **Epic**. An epic represents a feature area for Istio as a whole. Epics are fairly broad in scope and are basically product-level things. Each issue is ultimately part of an epic. - **Milestone**. Each issue is assigned a milestone. This is 0.1, 0.2, ..., or 'Nebulous Future'. The milestone indicates when we think the issue should get addressed. - **Priority**. Each issue has a priority which is represented by the column in the [Prioritization](https://github.com/orgs/istio/projects/6) project. Priority can be one of P0, P1, P2, or >P2. The priority indicates how important it is to address the issue within the milestone. P0 says that the milestone cannot be considered achieved if the issue isn't resolved. ---
Istio is a Cloud Native Computing Foundation project.