Single-cluster service mesh deployments might be all that is required in some environments. But other environments might call on the need for multiple clusters and single, global service mesh deployment or federation of independent service mesh deployments. Such environments can include consideration for existing monoliths or other external services. And although we’re all excited to see the day when microservices rule the world and monolithic applications are relegated to the dusty pages of history, we’re not there yet. The Istio project understands this and supports a variety of deployment and configuration models.
This chapter reviews a handful of the more common advanced topologies. Advanced topologies are useful in environments in which the focus strictly comprises geographically proximate microservices or environments that distribute service meshes across regions or providers.
Although numerous topology configurations are possible, here we discuss a core few that you can morph into other configurations. Let’s categorize these few into two foundational topologies deployed across a single cluster or multiple clusters.
An advanced single-cluster topology is that of mesh expansion. Mesh expansion is a topology that includes running traditional, nonmicroservice workloads (so, monolithic apps) on bare metal or VMs (or both) on your Istio service mesh. Though these apps don’t receive all of the ...