A kubernetes-based microservices architecture with databases

The following architecture illustration conveys a few ideas, but also lacks lots of details:

A kubernetes-based microservices architecture with databases

Details we get from the picture:

• The partner plans to run services on top of Kubernetes as an orchestrator

• There will be multiple services on the Kubernetes cluster

• Some services talk to each other

• Some services store data in databases

• The databases seem to be hosted on Kubernetes as well

• Some services call out to services outside of the Kubernetes cluster

Details we miss in the picture:

• What 'application' is calling the deployment, i.e. how do users interact with the system?

  • Is it a web-based application, where users use their browser? Is it a 'single-page application'? Server-rendered HTML?

  • Is it a 'fat client', like a Windows-application, running on the user's computer, which interacts with the system?

  • Is it a B2B-application, where your application exposes an API which is called from, and integrated, with your customed's business systems?

• How does traffic come into the application?

  • Does the application only expose a single endpoint, or IP address? Do you need multiple IP addresses?

  • Which protocols are used, is is web-based (HTTPs) traffic, IoT (AMQP/MQTT), which transports (TCP, UDP)

  • Do you have session-affinity requirements, a.k.a. sticky sessions, where subsequent requests need to be sent to the same compute node?

• Connectivity to external systems

  • The picture just says that the application talks to 3rd party services. Which services are that?

  • When talking to 3rd party services, do you have requirements for controlling the outbound IP address? For example, some 3rd party services have to lock-down incoming traffic using IP addresses (allow-listing), so you might have to be able to control outbound IP addresses.

• High-availability

  • Do you need to run your application in multiple cloud regions, or is it sufficient to run in a single one?

• Databases

  • Which types of databases are needed for the application?

    • Relational databases (MS SQL, MySQL/Maria, PostgreSQL)

    • Key-value stores (Redis, Memcache)

    • Document- and other NoSQL databases (MongoDB, Cassandra, ScyllaDB)

    • Message-centric brokers (RabbitMQ, Kafka, )

    • Extensions, such as TimescaleDB

  • The picture seems to say that the database system a

• Multi-tenancy