Istio vs linkerd: What are the differences?
Istio: Open platform to connect, manage, and secure microservices, by Google, IBM, and Lyft. 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, Mesos, etc; linkerd: Twitter-Style Operability for Microservices. linkerd is an out-of-process network stack for microservices. It functions as a transparent RPC proxy, handling everything needed to make inter-service RPC safe and sane--including load-balancing, service discovery, instrumentation, and routing.
Istio and linkerd can be categorized as "Microservices" tools.
Istio and linkerd are both open source tools. It seems that Istio with 18.5K GitHub stars and 3.1K forks on GitHub has more adoption than linkerd with 5.01K GitHub stars and 501 GitHub forks.