What Is Service Mesh in Kubernetes? 4 Tools to Get Started

What Is a Kubernetes Service Mesh?

A Kubernetes service mesh is a dedicated infrastructure layer designed to manage, observe, and control communication between microservices within a Kubernetes cluster. The main goal of a service mesh is to improve the overall reliability, Kubernetes security, and observability of the microservices that make up a complex, distributed application.

There are several popular open source technologies that can be used to implement a service mesh in Kubernetes clusters, including Istio, Linkerd, Consul Connect, and NGINX Service Mesh.

In this article:

• How a Service Mesh Can Help Kubernetes
• How Does a Kubernetes Service Mesh Work?
• 4 Kubernetes Service Mesh Tools
  • Istio
  • Linkerd
  • Consul Connect
  • NGINX Service Mesh
• Do you really need a service mesh? Calico offers an operationally simpler approach

How a Service Mesh Can Help Kubernetes

Kubernetes is a powerful platform for deploying and managing containerized applications at scale. However, as organizations move towards microservices architectures, the complexity of managing service-to-service communication can become challenging. This is where service mesh can help Kubernetes.

A service mesh can enhance Kubernetes by providing additional capabilities for managing and securing service-to-service communication within the Kubernetes cluster. Here are some ways in which service mesh can help Kubernetes:

• Traffic management: Service mesh can provide advanced traffic management capabilities like load balancing, service discovery, and traffic routing, which help ensure that application traffic is routed efficiently and reliably.
• Service-to-service communication: Service mesh enables service-to-service communication, which means that the communication between services is abstracted away from the application code. This makes it easier to manage, monitor, and secure the communication between services.
• Service-level observability: Service mesh provides rich observability features that enable teams to monitor and analyze the performance and behavior of services in real time. This can help identify and diagnose issues quickly, reducing the mean time to resolution.
• Security: Service mesh can improve the security of microservices-based applications by providing end-to-end encryption, mutual authentication, and authorization policies. This helps protect sensitive data and ensures that only authorized services can communicate with each other.
• Consistency: Service mesh provides a consistent way of managing and configuring services across the infrastructure. This can help reduce complexity and improve the reliability of applications.

Read our blog post: Do You Really Need a Service Mesh?

How Does a Kubernetes Service Mesh Work?

A Kubernetes service mesh works by providing a dedicated infrastructure layer that manages communication between microservices in a Kubernetes cluster. It uses sidecar proxies, a control plane, and a data plane to enable advanced features like observability, security, and traffic management. Let’s dive deeper into how these components work together.

Sidecar proxies
Each microservice in the Kubernetes cluster is paired with a sidecar proxy, which intercepts and manages all incoming and outgoing network traffic. These proxies are typically implemented using Envoy, a high-performance proxy. When a microservice sends or receives a request, the sidecar proxy handles the communication, abstracting the network complexities away from the microservice itself.

Control plane
The control plane is responsible for managing the configuration of the sidecar proxies. It provides an API and a set of tools for defining and enforcing policies, such as routing rules, load balancing settings, and security configurations, across the entire service mesh. The control plane also collects telemetry data from the sidecar proxies, allowing operators to monitor and troubleshoot the microservices and their interactions.

Data plane
The data plane consists of the sidecar proxies that process and forward network traffic between microservices. This layer is responsible for implementing the policies and configurations defined by the control plane, such as routing decisions, load balancing, and security settings.

When a request is made within the Kubernetes cluster, the following steps occur:

1. The source microservice sends the request to its corresponding sidecar proxy.
2. The sidecar proxy consults the control plane to determine the appropriate routing and security policies.
3. The sidecar proxy forwards the request to the destination sidecar proxy, applying any necessary load balancing, retries, or circuit breaking.
4. The destination sidecar proxy receives the request and forwards it to the destination microservice.
5. The destination microservice processes the request and sends the response back through the sidecar proxies, following the same process in reverse.

By using a service mesh, developers and operators can focus on implementing application logic rather than managing the complexities of inter-service communication. This results in improved observability, security, and resilience for microservices-based applications running on Kubernetes.

4 Kubernetes Service Mesh Tools

The following open source tools can help you implement a service mesh in your Kubernetes clusters.

Istio

License: Apache License 2.0
GitHub Repository: https://github.com/istio/istio

Istio is an open-source service mesh platform that helps manage traffic between microservices within a Kubernetes cluster. It provides features such as load balancing, authentication, authorization, rate limiting, and observability.

Istio uses a sidecar proxy (Envoy) that intercepts all incoming and outgoing traffic to handle service-to-service communication. It’s designed to be platform-independent and can be used in various environments like Kubernetes, Mesos, and others.

Read our blog post: How to Build a Service Mesh with Istio and Calico

Linkerd

License: Apache License 2.0
GitHub Repository: https://github.com/linkerd/linkerd2

Linkerd is another open-source service mesh that is focused on simplicity, performance, and security. Developed by Buoyant, Linkerd is designed to be lightweight and easy to use. Like Istio, it utilizes a sidecar proxy model to handle traffic between services.

Linkerd provides features such as load balancing, automatic retries, circuit breaking, and observability. It is part of the Cloud Native Computing Foundation (CNCF) and is built on the Rust-based proxy, Linkerd2-proxy.

Consul Connect

License: Mozilla Public License 2.0
GitHub Repository: https://github.com/hashicorp/consul

Consul Connect is a service mesh solution developed by HashiCorp as part of their Consul product, which is a service discovery and configuration tool. Consul Connect extends Consul’s capabilities to provide features such as service segmentation, mutual TLS encryption, and fine-grained access control for microservices.

It can be integrated with Kubernetes, VMs, and bare-metal servers. Consul Connect is designed to be highly scalable and can be used in multi-cloud and multi-platform environments.

NGINX Service Mesh

License: Apache License 2.0
GitHub Repository: https://github.com/nginxinc/nginx-service-mesh

NGINX Service Mesh is a lightweight, production-ready service mesh solution developed by NGINX (now part of F5 Networks). It’s built on the popular NGINX proxy and is designed to be easy to deploy and manage.

It provides features such as traffic management, security, and observability. NGINX Service Mesh uses a sidecar proxy model and supports integration with other NGINX products, such as NGINX Plus, for additional capabilities.

Do you really need a service mesh? Calico offers an operationally simpler approach

A service mesh adds operational complexity and introduces an additional control plane for teams to manage. Platform owners, DevOps teams, and SREs have limited resources, so adopting a service mesh is a significant undertaking due to the resources required for configuration and operation.

Calico enables a single-pane-of-glass unified control to address the three most popular service mesh use cases—security, observability, and control—with an operationally simpler approach, while avoiding the complexities associated with deploying a separate, standalone service mesh. With Calico, you can easily achieve full-stack observability and security, deploy highly performant encryption, and tightly integrate with existing security infrastructure like firewalls.

• Encryption for data in transit – Calico leverages the latest in crypto technology, using open-source WireGuard. As a result, Calico’s encryption is highly performant while still allowing visibility into all traffic flows.
• Dynamic Service and Threat Graph – Kubernetes-native visualization of all collected data that allows the user to visualize communication flows across services and team spaces, to facilitate troubleshooting.
• Operational simplicity with Envoy integrated into the data plane – Calico provides observability, traffic flow management, and control by deploying a single instance of Envoy as a daemon set on each node of your cluster, instead of a sidecar approach, thus making it more resource efficient and cost effective.
• Zero-trust workload access controls – Integrate with firewalls or other kinds of controls where you might want to understand the origin of egress traffic. Identify the origin of egress traffic, to the point where you have visibility into the specific application or namespace from which egress traffic seen outside the cluster came.

Next steps:

• Blog: Do you really need a service mesh?
• Webinar: Is service mesh the only option to secure application layer traffic?
• Blog: How to build a service mesh with Istio and Calico
• Blog: Using Calico Egress gateway and access controls to secure traffic