Istio in 2020 - Following the Trade Winds

Istio solves real problems that people encounter running microservices. Even very early pre-release versions helped users debug the latency in their architecture, increase the reliability of services, and transparently secure traffic behind the firewall.

Last year, the Istio project experienced major growth. After a 9-month gestation before the 1.1 release in Q1, we set a goal of having a quarterly release cadence. We knew it was important to deliver value consistently and predictably. With three releases landing in the successive quarters as planned, we are proud to have reached that goal.

During that time, we improved our build and test infrastructure, resulting in higher quality and easier release cycles. We doubled down on user experience, adding many commands to make operating and debugging the mesh easier. We also saw tremendous growth in the number of developers and companies contributing to the product - culminating in us being #4 on GitHub’s top ten list of fastest growing projects!

We have ambitious goals for Istio in 2020 and there are many major efforts underway, but at the same time we strongly believe that good infrastructure should be “boring.” Using Istio in production should be a seamless experience; performance should not be a concern, upgrades should be a non-event and complex tasks should be automated away. With our investment in a more powerful extensibility story we think the pace of innovation in the service mesh space can increase while Istio focuses on being gloriously dull. More details on our major efforts in 2020 below.

Sleeker, smoother and faster

Istio provided for extensibility from day one, implemented by a component called Mixer. Mixer is a platform that allows custom adapters to act as an intermediary between the data plane and the backends you use for policy or telemetry. Mixer necessarily added overhead to requests because it required extensions to be out-of-process. So, we’re moving to a model that enables extension directly in the proxies instead.

Most of Mixer’s use cases for policy enforcement are already addressed with Istio’s authentication and authorization policies, which allow you to control workload-to-workload and end-user-to-workload authorization directly in the proxy. Common monitoring use cases have already moved into the proxy too - we have [introduced in-proxy support]/docs/ops/configuration/telemetry/in-proxy-service-telemetry/) for sending telemetry to Prometheus and Stackdriver.

Our benchmarking shows that the new telemetry model reduces our latency dramatically and gives us industry-leading performance, with 50% reductions in both latency and CPU consumption.

A new model for Istio extensibility

The model that replaces Mixer uses extensions in Envoy to provide even more capability. The Istio community is leading the implementation of a WebAssembly (Wasm) runtime in Envoy, which lets us implement extensions that are modular, sandboxed, and developed in one of over 20 languages. Extensions can be dynamically loaded and reloaded while the proxy continues serving traffic. Wasm extensions will also be able to extend the platform in ways that Mixer simply couldn’t. They can act as custom protocol handlers and transform payloads as they pass through Envoy — in short they can do the same things as modules built into Envoy.

We’re working with the Envoy community on ways to discover and distribute these extensions. We want to make WebAssembly extensions as easy to install and run as containers. Many of our partners have written Mixer adapters, and together we are getting them ported to Wasm. We are also developing guides and codelabs on how to write your own extensions for custom integrations.

By changing the extension model, we were also able to remove dozens of CRDs. You no longer need a unique CRD for every piece of software you integrate with Istio.

Installing Istio 1.5 with the ‘preview’ configuration profile won’t install Mixer. If you upgrade from a previous release, or install the ‘default’ profile, we still keep Mixer around, to be safe. When using Prometheus or Stackdriver for metrics, we recommend you try out the new mode and see how much your performance improves.

You can keep Mixer installed and enabled if you need it. Eventually Mixer will become a separately released add-on to Istio that is part of the istio-ecosystem.

Fewer moving parts

We are also simplifying the deployment of the rest of the control plane. To that end, we combined several of the control plane components into a single component: Istiod. This binary includes the features of Pilot, Citadel, Galley, and the sidecar injector. This approach improves many aspects of installing and managing Istio – reducing installation and configuration complexity, maintenance effort, and issue diagnosis time while increasing responsiveness. Read more about Istiod in this post from Christian Posta.

We are shipping istiod as the default for all profiles in 1.5.

To reduce the per-node footprint, we are getting rid of the node-agent, used to distribute certificates, and moving its functionality to the istio-agent, which already runs in each Pod. For those of you who like pictures we are moving from this …

to this…

In 2020, we will continue to invest in onboarding to achieve our goal of a “zero config” default that doesn’t require you to change any of your application’s configuration to take advantage of most Istio features.

Improved lifecycle management

To improve Istio’s life-cycle management, we moved to an operator-based installation. We introduced the IstioOperator CRD and two installation modes:

• Human-triggered: use istioctl to apply the settings to the cluster.
• Machine-triggered: use a controller that is continually watching for changes in that CRD and affecting those in real time.

In 2020 upgrades will getting easier too. We will add support for “canarying” new versions of the Istio control plane, which allows you to run a new version alongside the existing version and gradually switch your data plane over to use the new one.

Secure By Default

Istio already provides the fundamentals for strong service security: reliable workload identity, robust access policies and comprehensive audit logging. We’re stabilizing APIs for these features; many Alpha APIs are moving to Beta in 1.5, and we expect them to all be v1 by the end of 2020. To learn more about the status of our APIs, see our features page.

Network traffic is also becoming more secure by default. After many users enabled it in preview, automated rollout of mutual TLS is becoming the recommended practice in Istio 1.5.

In addition we will make Istio require fewer privileges and simplify its dependencies which in turn make it a more robust system. Historically, you had to mount certificates into Envoy using Kubernetes Secrets, which were mounted as files into each proxy. By leveraging the Secret Discovery Service we can distribute these certificates securely without concern of them being intercepted by other workloads on the machine. This mode will become the default in 1.5.

Getting rid of the node-agent not only simplifies the deployment, but also removes the requirement for a cluster-wide PodSecurityPolicy, further improving the security posture of your cluster.

Other features

Here’s a snapshot of some more exciting things you can expect from Istio in 2020:

• Integration with more hosted Kubernetes environments - service meshes powered by Istio are currently available from 15 vendors, including Google, IBM, Red Hat, VMware, Alibaba and Huawei
• More investment in istioctl and its ability to help diagnose problems
• Better integration of VM-based workloads into meshes
• Continued work towards making multi-cluster and multi-network meshes easier to configure, maintain, and run
• Integration with more service discovery systems, including Functions-as-a-Service
• Implementation of the new Kubernetes service APIs, which are currently in development
• An enhancement repository, to track feature development
• Making it easier to run Istio without needing Kubernetes!

From the seas to the skies, we’re excited to see where you take Istio next.