Istio
An open platform to connect, manage, and secure microservices.
- For in-depth information about how to use Istio, visit istio.io
- To ask questions and get assistance from our community, visit discuss.istio.io
- To learn how to participate in our overall community, visit our community page
In this README:
In addition, here are some other documents you may wish to read:
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.
-
Mixer - Central component that is leveraged by the proxies and microservices
to enforce policies such as authorization, rate limits, quotas, authentication, request
tracing and telemetry collection.
-
Pilot - A component responsible for configuring the proxies at runtime.
-
Citadel - A centralized component responsible for certificate issuance and rotation.
-
Citadel Agent - A per-node component responsible for certificate issuance and rotation.
-
Galley- Central component for validating, ingesting, aggregating, transforming and distributing config within Istio.
Istio currently supports Kubernetes and Consul-based environments. We plan support for additional platforms such as
Cloud Foundry, and Mesos in the near future.
Repositories
The Istio project is divided across a few GitHub repositories.
-
istio/istio. This is the main repository that you are
currently looking at. It hosts Istio's core components and also
the sample programs and the various documents that govern the Istio open source
project. It includes:
-
security. This directory contains security related code,
including Citadel (acting as Certificate Authority), citadel agent, etc.
-
pilot. This directory
contains platform-specific code to populate the
abstract service model, dynamically reconfigure the proxies
when the application topology changes, as well as translate
routing rules into proxy specific configuration.
-
istioctl. This directory contains code for the
istioctl command line utility.
-
mixer. This directory
contains code to enforce various policies for traffic passing through the
proxies, and collect telemetry data from proxies and services. There
are plugins for interfacing with various cloud platforms, policy
management services, and monitoring services.
-
istio/api. This repository defines
component-level APIs and common configuration formats for the Istio platform.
-
istio/proxy. The Istio proxy contains
extensions to the Envoy proxy (in the form of
Envoy filters), that allow the proxy to delegate policy enforcement
decisions to Mixer.
Issue management
We use GitHub combined with ZenHub 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/Pipeline. Each issue has a priority which is represented by the Pipeline field within GitHub. 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.
We don't annotate issues with Releases; Milestones are used instead. We don't use GitHub projects at all, that
support is disabled for our organization.
