What is containers as a service (CaaS)?

Containerized applications are composed of software code packaged with just the operating system (OS) libraries and dependencies required to run them. They are agile, executable units (containers) that can run on virtually any IT infrastructure, from on-premises data centers to hybrid cloud and multicloud environments.

CaaS sits between infrastructure as a service (IaaS) and platform as a service (PaaS) in the cloud computing stack, providing a balance between the control offered by IaaS and the simplicity of PaaS.

Infrastructure as a service (IaaS) is a foundational cloud model, allowing organizations to virtualize computing, networking and storage resources, and run other cloud services like software as a service (SaaS) or PaaS. IaaS platforms let teams fully customize components, from application stacks to operating systems, but the vendor manages computer resources and hardware.

Platform as a service (PaaS) functions at the code-stack level, letting users focus on higher-level app dependencies (for example, language runtimes). Still, it eliminates user control of the OS and limits portability across deployment environments. (Learn more about the difference between IaaS, PaaS and SaaS.)

CaaS puts the control back in the users’ hands by facilitating OS virtualization and customization and enabling container-specific deployment.

Containers as a service (CaaS) provides a cloud-based platform where users can streamline container-based virtualization and container management processes. CaaS providers offer myriad features, including (but not limited to) container runtimes, orchestration layers and persistent storage management. CaaS also has unique integration capabilities that help businesses optimize their IT infrastructure.

Primary CaaS features include the following:

• Containerization
• Container orchestration
• Networking
• Platform configuration
• Security and access control
• Integration with other services

When a user only works with a few containerized apps, it’s feasible to manage the containerization process manually. However, companies are increasingly relying on containers to make their IT infrastructure more agile, which means managing larger volumes of containers. CaaS allows teams to automate the containerization process to use the portability of containers at scale.

It’s worth noting that Docker was the first open source software tool to popularize building, deploying and managing containerized applications. However, the Docker container platform lacked an automated “orchestration” tool, which made it time-consuming and complex for data-science teams to scale applications. Kubernetes, also called K8s, was created to address these challenges by automating the management of containerized applications. Both Docker and Kubernetes are considered industry standards for containerized development and deployment.

The orchestration layer of a CaaS system facilitates automated container deployment, load balancing, scheduling, scaling and lifecycle management processes across the IT ecosystem. As mentioned, the most popular container orchestration platform is the open source, Linux-based Kubernetes service, but other leading public cloud providers and cloud technology companies offer their own high-quality container orchestration services, including the following:

• AWS’s Amazon Elastic Container Service (Amazon ECS)

• Google Cloud’s Google Kubernetes Engine (GKE)

• Docker Swarm

• IBM Cloud® Kubernetes Service

• Microsoft Azure Container Instances (ACI)

CaaS platforms facilitate smooth communication between containers by using network overlays and software-defined networking (SDN) technologies to create virtual networks and optimize container connectivity.

Users interact with container platforms through high-level, customizable application programming interfaces (APIs) or web portal interfaces that enable them to define resource requirements, networking settings and environment variables for containers and associated resources.

CaaS systems typically include flexible security features like role-based access control (RBAC), container isolation and container image scanning for vulnerabilities and network policies. These tools help organizations monitor and control traffic flow between containers in real time.

One of the most impressive features of CaaS is its ability to integrate with other cloud-native technologies, such as managed databases, caching systems and message queues. For instance, CaaS can integrate with continuous integration/continuous delivery (CI/CD) and DevOps pipelines to accelerate product improvement and development processes.

Containers as a service (CaaS) enables businesses to focus on core competencies by abstracting the complexities of infrastructure management. With CaaS, developers can prioritize building and deploying apps without worrying about the underlying infrastructure or storage requirements.

Other notable benefits include the following: 

• Scalability
• Portability
• Efficiency
• Collaboration
• Cost-effectiveness
• Support AI and ML workloads

Businesses across sectors are turning to containers as a service (CaaS) for cloud solutions. In fact, the global CaaS market was valued at nearly USD 2 billion in 2022.¹ Researchers anticipate that the market will be worth more than USD 7 billion by 2027, with a CAGR of 30.2% during that period.² With market growth expected to accelerate in the coming years, it’s clear that CaaS services are becoming increasingly valuable for app developers worldwide.

Teams can use CaaS to build a microservices architecture, which breaks down apps into smaller services that can be developed, deployed and scaled independently. Implementing microservices improves the overall agility and speed of application development processes.

CaaS can also facilitate the transition to DevOps culture, wherein software development and IT operations teams work together throughout the software lifecycle. CaaS offers a shared platform where the teams can collaborate to develop and ship end products that better serve the user.

Furthermore, app containerization enables teams to modernize legacy applications faster. Containerized apps are especially portable, allowing teams to use the benefits of modern, cloud-native application development without needing to rewrite their applications from scratch.