Luke Kysow is a software engineer at HashiCorp, and he's in conversation with host Robert Blumen. The subject of their discussion is on the idea of a service mesh. As software architecture moved towards microservices, several reusable pieces of code needed to be configured for each application. On a macro scale, load balancers need to be configuring to control where packets are flowing; on a micro level, things like authorization and rate limiting for data access need to be set up for each application. This is where a service mesh came into being. As each microservice began to call out to each other, shared logic was taken out and placed into a separate layer. Now, every inbound and outbound connection--whether between services or from external clients--goes through the same service mesh layer.

Extracting common functionality out like this has several benefits. As containerization enables organizations to become more polyglot, service meshes provide the opportunity to write operational logic once, and reuse it everywhere, no matter the base application's language. Similarly, each application does not need to rely on its own bespoke dependency library for circuit breakers, rate limiting, authorization and so on. The service mesh provides a single place for the logic to be configured and everywhere. Service meshes can also be useful in metrics aggregation. If every packet of communication must traverse the service mesh layer, it becomes the de facto location to set up counters and gauges for actions that you're interested in, rather than having each application send out non-unique data.

Luke notes that while it's important for engineers to understand the value of a service mesh, it's just as important to know when such a layer will work for your application. It depends on how big your organization is, and the challenges you're trying to solve, but it's not an absolutely essential piece for every stack. Even a hybrid approach, where some logic is shared and some is unique to each microservice, can be of some benefit, without necessarily extracting everything out.

Links from this episode

• HashiCorp helps automate infrastructure configuration
• Consul, Linkerd, Istio, and Kuma are several open source components for service meshes and control planes
• Mastering Service Mesh: Enhance, secure, and observe cloud-native applications with Istio, Linkerd, and Consul by Anjaki Khatri and Vikram Khatri
• Consul service mesh
• What's a service mesh? And why do I need one? by William Morgan offers additional advice on when to use service meshes
• The Service Mesh: What Every Software Engineer Needs to Know about the World's Most Over-Hyped Technology
• What is a Service Mesh? - a blog from NGINX