Serverless vs Containers: What's Right for Your Application?

In the world of cloud-based computing, there are two main approaches to deploying applications: containers and serverless. Each has its advantages and disadvantages. So which one -- serverless vs containers -- is right for your applications?

In this post, I'll compare the two methods of code and application deployment on various parameters to help you determine which one is best for you. First, let's start with a brief overview of each.

What Are Container-Based Applications?

Containers are lightweight virtual machines or self-contained units of deployment. They allow you to package all the dependencies necessary to run your application within a self-contained unit. Running an application using containers means that you must first package your application and its dependencies to run it into a container like Docker. Then you can run these containers on any server.

Figure 1: Container-based applications

To run an application in a container, start by building an image (such as a Docker image), a template used to create a container. You can create images using a text file known as a Dockerfile that contains instructions describing how to build a Docker image. With unique configurations and settings, you can use this image to create as many containers as you wish. You can then run them anywhere without requiring other libraries or tools as long as you have a container runtime technology like Docker Engine installed.

Since containers offer an isolated environment for your code, they're ideal for deployments on cloud platforms like Amazon Web Services (AWS), Google Cloud Platform, and Microsoft Azure. You may also use a container orchestration platform like Kubernetes to deploy and manage containers at scale. This makes them suitable for deployments in the cloud as you can quickly move them from one server to another without worrying about compatibility issues.

What are Serverless Applications?

Serverless applications run in a completely stateless environment. In a serverless application, you use a Function as a Service (FaaS) that packages and deploys code as a standalone executable. The code responds to events like an incoming HTTP request or a file upload to an S3 bucket. Running a serverless application means you don't need to provision or manage traditional servers. The cloud provider's infrastructure executes the application as required and shuts it down when it's no longer necessary. Several FaaS offerings include AWS Lambda, Azure Functions, and Google Cloud Functions. Serverless applications can significantly simplify deploying and managing applications as there is no need to worry about servers or scaling.

Figure 2: Serverless application

This approach is simpler to manage than using containers and can be cheaper since you only pay for the time your code is running. However, serverless deployments are less flexible and can be less efficient.

Applications: Containers vs Serverless

Now that you have a basic understanding of these approaches, let's look at the pros and cons of each.

Ease of Development

Developers are constantly under pressure to quickly produce high-quality code. This can be a daunting task, especially when you're working with a new technology. Ease of development is the ability to develop an application quickly and easily. This can be measured in a number of ways, such as how quickly you can get up and running, how easy it is to make changes, and how many errors you encounter.

Container-Based Applications

You can develop containerized applications using a framework or programming language of your choice, which is then compiled into a binary that can run on any machine that has the same runtime dependencies. With containers, you can quickly spin up a development environment that matches the production environment. This allows for faster development and fewer surprises in production. It also makes it easy to develop and test applications on your local machine. If you're already familiar with Docker and how to create images, you'll likely be up and running with a container-based application in no time.

Serverless Applications

Serverless applications typically use one of the popular programming languages, but you don't compile them into a binary. Instead, you package them into a function. You must use a provider's portal or command line interface to test and deploy them. It's easier to develop serverless applications than their containerized counterparts. This is because you don't need to worry about setting up or managing container or servers. The provider takes care of that for you. This allows you to focus on developing your code. You can also build and test your code in a local environment.

Ease of Deployment

Deployment is a critical process as it places code into production. It includes configuring code for use in a live environment, testing it to ensure that it works as expected, and then deploying it to one or more servers. Once you deploy the code, you need to configure and manage your environment so that it runs smoothly and meets your business or organizational needs

Container-based applications

Container-based applications are easy to deploy as you can package them and move them to any server without worrying about compatibility issues. You can also use a container orchestration platform like Kubernetes to deploy and manage containers at scale. Containerized applications can also be deployed using automation tools like Puppet, Chef, or Ansible. This makes it easy to deploy them on multiple machines.

Serverless Applications

With a serverless application, you don't need to provision any infrastructure, but you do need a FaaS provider. These providers offer a more limited set of features than container platforms. Serverless applications are deployed using a cloud provider's portal or command line interface. This might require a learning curve, but it's usually easy. There is no guarantee that the deployment will always go smoothly. Each provider has different methods of deploying an application, and it's your responsibility to set up and maintain your code yourself. While there are many public libraries and tools, it can be difficult to find the right one for your specific application and platform.

Cloud Computing Cost

Many companies depend on public cloud services providers for their infrastructure needs. Cloud computing cost is the cost for the use of cloud services like compute, storage, and networking resources.

Container-Based Applications

Container-based applications can be more expensive to run than serverless applications. This is because containers typically require more resources (e.g., CPU, memory, disk). As a result, your cloud bill will be higher if you choose to deploy a container-based application on a public cloud provider.

Serverless Applications

Serverless applications are often much cheaper to run than container-based applications. This is because you only pay for the time your application is actually executing rather than the entire time your servers are running (which can be 24/7). Additionally, serverless applications automatically scale to meet demand, so you don't have to worry about provisioning extra servers when your traffic spikes.

Portability

Portability is the ability to move an application from one provider to another with relative ease.

Container-Based Applications

You can move a container-based application from one provider to another with minimal effort. Cloud-native applications are built to take advantage of the cloud. They're designed to be portable, scalable, and resilient. In a cloud-native application, you'll typically find microservices that you can deploy and scale easily.

Container-based applications are a great fit for cloud-native applications. Containers make it easy to package and deploy code as a standalone executable. They also allow you to run multiple containers on the same server, making it easy to scale your application.

Serverless Applications

Serverless applications are not as portable as container-based applications. This is because a serverless application is tightly coupled with the provider's infrastructure. If you want to move your application to another provider, you will likely need to spend a significant amount of time and effort modifying your code. One of the main disadvantages of using serverless applications is vendor lock-in. Vendor lock-in occurs when you're locked into a specific vendor and can't easily switch to a different provider. This can be a problem if the provider you're locked in to decides to raise prices or change the terms and conditions.

Scalability and Performance

Scalability measures how well a system or application can maintain performance as it supports an increased number of users or traffic. Performance is how quickly a system or application performs when handling a given level of workload.

Container-Based Applications

Containerized applications are typically much more scalable than serverless applications because you can easily add or remove containers to meet your scaling needs. Additionally, containers offer a higher degree of isolation than serverless applications. If one container fails, it will not impact others. However, this can be a problem with serverless applications.

Serverless Applications

A serverless platform maintains scalability and performance in response to incremental load challenges. It is not suitable for applications that require quick responses. You may experience some latency compared to running your application on dedicated servers because a cloud provider executes serverless applications on demand.

Security Considerations

Security is always a critical consideration for any application.

Serverless Applications

By default, serverless applications are secure. Serverless platform providers take care of many security tasks, such as patching, that you would otherwise have to do yourself. Additionally, most FaaS providers offer built-in security features, such as encryption and access control.

However, serverless applications can be vulnerable to dedicated denial-of-service (DDoS) attacks. Because your application is running on a provider's infrastructure, a hacker may be able to send many requests to your application at once, overwhelming it and taking it down.

You generally use popular frameworks like Node.js to create serverless applications, which might have some inherent security flaws. If your application is not adequately secured, hackers could compromise it.

Container-Based Applications

You can make container-based applications more secure than serverless applications. By running them on dedicated infrastructure, you can better safeguard your application than if you use a cloud provider's infrastructure.

Additionally, because containers are self-contained, it's usually more difficult for hackers to access the code and data. However, you need to manage the security of your containers yourself, which can be difficult if you're not a security expert.

Conclusion: Serverless vs Containers

If you need a high degree of isolation or scalability, containers may be the right choice. However, if you need simplicity and ease of development, serverless may be the way to go. Container-based applications offer more flexibility and control than serverless but require more management and expertise. But there are also some potential downsides to using containers. They require you to manage and configure servers, and they can be more challenging to develop than serverless applications.

So, which option is right for you? Ultimately, the decision comes down to your specific use case.

This post was written by Tarun Telang. Tarun is a software engineering leader with over 16 years of experience in the software industry with some of the world’s most renowned software development firms like Microsoft, Oracle, BlackBerry, and SAP. His areas of expertise include Java, web, mobile, and cloud. He’s also experienced in managing software projects using Agile and Test Driven Development methodologies.