Modern applications are increasingly being built as a set of microservices, which operate independently but work together to deliver complex services. In this model, each microservice can be written in a different programming language, use a separate database, and even run on different servers. With its support for many technologies and tools, Java is one of the most popular languages for creating microservices.
However, managing such a complex system as a set of microservices can be a challenge. Here is where Kubernetes, an open-source system for managing and scaling containers, comes in.
Kubernetes, also known as K8s, is a platform that automates processes related to deploying, scaling, and managing containerized applications. Java applications can be easily “containerized” using tools like Docker and then managed using Kubernetes.
Kubernetes allows for easy application scaling – both manual and automatic. Thanks to the autoscaling feature, K8s can automatically adjust the number of service instances based on current needs and metrics such as CPU or memory usage. This is particularly useful in banking systems, where the load can significantly vary depending on the time or day of the week.
Each microservice in a Java application can have its independent database. This is particularly important in banking systems, where different services may need different databases. For example, a service handling transactions might need a SQL database for transactionality and consistency. In contrast, a service analyzing customer data might benefit from a NoSQL database for better performance with large amounts of data.
Managing such services and databases becomes more straightforward, thanks to Kubernetes. We can define what resources are needed for each service, and K8s will handle the rest – running the service, monitoring its state, and even restarting it if necessary.
To illustrate the concept, envision yourself managing a massive bank with numerous branches analogous to microservices. Each branch specializes in a different area, e.g., one handles transactions, another analyzes customer data, and another deals with loans. Each component operates independently, but together, they create a complex network of services.
Here, Kubernetes acts like a smart manager that helps manage all these branches. It automates processes related to deploying, scaling, and managing the branches to ensure the bank’s operation is as efficient as possible. If it suddenly notices many more customers in one unit (here: server load), it can shift resources (e.g., employees) from other branches to meet the increased demand. This is scaling – both manual and automatic.