Service Mesh comparison – Istio vs LinkerD

What is a service mesh?

A service mesh is in charge of managing the network traffic between the services. It does it in a more automated and scalable way compared to otherwise what it would take a lot of manual work. (and we know that manual work is not good 🙂 )

In other words, the service mesh lays in top of Kubernetes, takes over your services networking and makes the communications safe and reliable. It allows to connect, secure and monitor your services.

You can focus on writing your microservices and leverage the observability, network, and security policies to the service mesh.

Key capabilities of a service mesh

We can split the key capabilities in three:

• Traffic Management
  • mTLS
  • Fault Injection
  • Circuit Breaking
  • Deployment Strategies
    
• Metrics/Observability
  • Out-of-the-box monitoring and tracing tools
    
• Security/Policies
  • Enforce policies and isolation

A service mesh enables “intelligent route control” capabilities, along with end-to-end encryption in the communications between the services. In addition, it also enables fault injection and advanced deployment strategies like blue/green, canaries, rolling upgrades, and more.

A service mesh becomes the “dashboard of your microservices“, a place where you can view and control what’s going on inside your cluster.

Service mesh comparison

When it comes to service mesh for Kubernetes, there are two big players, Istio and LinkerD. Both have amazing features and work in a very similar way so it is often a complicated choice.

Istio

• Istio is a Kubernetes native service mesh, but it supports other orchestration tools like Consul and even VMs.
• It was created by Lyft, but Google and IBM are now supporting it. Today Anthos comes with “Istio” service mesh capabilities.
• It relies on a control plane and sidecars for working
• We can say it is the most popular Kubernetes Service Mesh
• It is very customizable
• It is complex

LinkerD

• Mirrors Istio architecture closely. (sidecars, control plane)
• It is part of the Cloud Native Foundation (CNCF)
• LinkerD focuses on simplicity instead of Flexibility
• It is a Kubernetes-only solution
• We can say it is the second most used Kubernetes service mesh

Comparison Table

Here you can find a summary of a comparison between the features:

	ISTIO	LINKERD
Mesh Features
Encrypted traffic	Yes. Auto mTLS	Yes, but not for TCP. (mongo connection)
Inter microservices traffic management	Yes. Policies	Limited
Microservices metrics for automatic scalability	Yes. Prometheus	Yes. Prometheus
Real-time mesh status observability	Yes. Kiali. (more graphical)	Yes. (own dashboard, simpler)
Microservices Rate Limiting	Yes	No
Microservices Testing Features (fail injection, delays, % balancer)	Yes	Limited
Microservices Circuit breaking	Yes	No
Microservices Release mechanisms (canary, green/blue, etc.)	Yes	Yes
Monitoring integration and metrics standards (opentelemetry)	Yes. Grafana, Jaeger (tracing)	Yes
Access Logs Generation	Yes	No out-of-the-box (possible with plugins)
Does it work for Inter-cluster communications? (multi-cluster)	Yes	No
Mesh Generic stuff
Complexity	High	Low
Easy of Use	Complex	Medium
Companies behind it	Google, Lyft, IBM	Buoyant
Market acceptance/maturity. Community size	Large	Medium
Support Model	Community and Google on Anthos	Community. Buoyant
License/Cost	Apache 2.0	Apache 2.0
Pros	Many Features. Can be extended.	Easy to Use
Cons	Complex	Deeply Integrated with kubernetes. Cannot be expanded.

Comparison Conclusion

In conclusion, Istio is very flexible, but it is also very complex, therefore the learning curve is really big, yet it allows you to do more. LinkerD on the other hand focuses on simplicity, so it is easy to use but less customizable.