In this article we will discuss about serverless microservices, also will try to under what is microservices and what is use of it and how we can implement in out applications.
Table of Contents
What is a microservice?
Imagine taking an application, chopping it into pieces, and running it as a collection of those smaller parts rather than one huge whole. That is basically a microservices architecture. Each chunk of your application is known as a ‘microservice,’ and it only does one service, runs independent of the other chunks of the application, operates in its own environment, and stores its own data. As the name may suggest, it doesn’t necessarily mean that microservices have to be small. What makes them ‘micro’ is they only handle one service and are part of a larger application.
For example, consider an application that has microservices: Imagine you are a member of an American football team where each player is doing something a little different, but the players as a whole constitute a team -a whole application-which together achieve an outcome. Alternatively, consider microservices as being like body systems (circulatory, respiratory, etc.) and an application as a whole body.
From the perspective of the user, an application designed with microservices will have one interface, and it should behave exactly like a one-stack-designed application, but behind the scenes, each microservice has its database and is running independently of the rest of the application. Moreover, the different microservices in the same application can be written in different languages and will be using a different set of libraries.
Microservices are often contrasted with monolithic architecture. The classical way of building an application is monolithic architecture. A monolithic application is essentially one stack with the user interface on top, business logic in the middle, and the database at the bottom. Typically, a monolithic application runs on a particular server or set of servers. One of the disadvantages of developing an application in this way is that even the minuteest change to the application forces one to upgrade the whole stack. The other disadvantage is that the whole application breaks when one part of the application has broken.
Advantages of microservices
- Resilience: Since the application is divided into pieces, the breaking or crashing of one part of the application does not affect the rest of the application.
- Selective scalability: Instead of scaling the application as a whole, it is possible to only scale the microservices that see much usage
- Easier feature addition or updates: Features can be rolled out or updated individually and not the entire application stack
- Flexibility for developers: Microservices could be written in different programming languages and may have their libraries
Can microservices be part of a serverless architecture?
One can deploy microservices in quite a few ways; they can be part of a serverless architecture, hosted in containers, or developed using PaaS. However, the advantages of building an application out of microservices are perhaps most apparent when the application is hosted in the cloud, either using containers or in a serverless architecture.
What Are Serverless Microservices?
Cloud-based services offering the capabilities of serverless microservices make extensive use of serverless functions to perform a highly specific role within an application. Serverless functions are very modular and easy to scale as they execute small segments of code in response to events; therefore, they come particularly useful for microservice-based architectures. Serverless functions are also very easily consumable as a range of managed services; therefore, this minimizes the overhead usually associated with the majority of microservice implementations.
We’ll discuss how microservices are organized in a serverless context, what advantages and disadvantages serverless microservices have, and which tools are applicable for performance monitoring.
What's the difference between a microservice and a serverless function?
This trend continues to evolve, but, in general, a microservice is larger and more sophisticated than a function. A function is a relatively small piece of code that performs only one thing as an effect of something else happening. Depending on how developers have subdivided an application, a microservice may be equivalent to a function-meaning it does just one thing-or it may be composed of several functions.
Continue the football metaphor into all the responsibilities of a quarterback: passing the ball; handing the ball off to the running back, and so on. If the quarterback is like a microservice in the larger context of the team (offering the service of being a ‘quarterback’), then each of those smaller activities is a function. However, it is sometimes difficult to distinguish a microservice from a function, and there do exist particular soccer players who only have one task, like the kicker.
You can also read : What is gRPC in microservices?
Monoliths vs. Microservices
Monolithic applications would be built and deployed as one piece and unit, whereas microservice-based applications consist of multiple small, scalable services that can be developed and operated independently of each other. For instance, an e-commerce application may have entirely different microservices for the product catalogue, checkout workflow, and shipping process, so it may have its language, database, and libraries within those services. This paradigm of design enhances the resiliency of an application since an error in one service would never disturb other services. Microservices can be hosted on containers, virtual machines, on-premise servers, or serverless functions.
How do serverless microservices work?
A serverless microservice is made up of serverless functions that run small bits of code in response to HTTP requests, file downloads, database updates, and other events. It is managed by cloud providers so that all the underlying infrastructure that is necessary for running function code is automatically managed and taken care of, reducing overheads in the operation and letting developers focus on the application logic.
A single microservice may contain one or several functions deployed at once. For example, an e-commerce web application shipping microservice can be broken into several functions. When an order has its status marked as shipped, that’s one event which will trigger one function to validate the customer’s address, validated that causes another function that will create the shipping label. And finally, creating the label could invoke a final action that would send a shipping confirmation e-mail to the customer.
Benefits and Use Cases of Serverless Microservices
While serverless microservices inherit all the overall benefits of serverless architecture, such as fewer overheads and greater cost efficiency, their main advantage lies in how easily you can combine serverless functions with other managed services. To integrate functions with databases, message queues, and API management tools, similar mechanisms are used for different use cases. This then means that the functions and the resources applied in one microservice may provide a basis to other microservices. For instance, a workflow meant for validation could share similar logic and elements as authentication. This does mean the boilerplate code decreases with the scaling out of your application.
Complex, rapidly changing applications fit well into serverless microservices because of their modularity, making them manageable and scalable. In addition, an application can be broken down into separate services where each such service may, in turn, be composed of short-running, event-driven tasks, which suggests the suitability of using serverless microservices for an application. Monolithic code is usually suited for applications with consistent loads or applications that rely on performing prolonged operations.
Challenges of Serverless Microservices
Serverless microservices allow the engineering teams to do quick iteration and in a cost-effective way. However, they also have challenges associated with them:
1. Defining function boundaries
Teams may struggle to define the boundary for each function in their microservices. While each function needs a defined role, spreading logic over too many functions often makes it cumbersome to update or extend. Teams need to balance the deployment of a practicable few functions with defining a specific and unique responsibility to each function.
2. Optimization of Function Performance
Some performance problems are specific only to serverless environments. An example is the problem of cold starts – after a while, there is no interaction at all, and then a function is called in response. Such starts make the algorithm more latency-prone. Teams can use Provisioned Concurrency to prevent cold starts; however, it might only increase the costs of deployment and rarely helps.
3. Monitoring
A single application may comprise tens or hundreds of short-lived microservices and functions that cross boundaries with a wide variety of other resources. This may become really challenging to trace requests across your environment, know your dependencies, and isolate errors. In order to optimize and troubleshoot serverless microservices, visibility into how a team’s functions and services interplay with each other is quite important.
Teams can solve some of these concerns above by adopting microservices and functions incrementally. For instance, they might choose to migrate all code of a given service to one function to get accustomed to the writing and deploying of function code. They also may choose to move only noncritical microservices to serverless architecture and gradually increase the adoption of functions going forward.
Monitoring Serverless Microservices
Monitoring is one of the biggest challenges towards successfully implementing serverless microservices. Their inherent complexity also makes it difficult to even determine, say, if an error is a function timeout or some type of problem with another downstream service.
Also read : Complete Guide to Deploying Your .NET Core Application on the Cloud
