What is Container as a Service (CaaS)?
Containers as a Service (CaaS) is a cloud service that manages containers at large scale, including starting, stopping, scaling, and organizing containerized workloads. Examples of CaaS services are Amazon Elastic Container Service (ECS), Amazon Fargate, and Azure Container Instances (ACI).
CaaS container platforms are a middle ground between container engines like Docker, which let you manage individual containers without orchestration capabilities, and full-featured orchestrators like Kubernetes, which provide powerful cluster management capabilities, but are complex to setup and maintain.
Within the scope of cloud computing services, CaaS provides more capabilities than Infrastructure as a Service (IaaS), but has less features than most Platform as a Service (PaaS) offerings. CaaS is most commonly deployed in an IaaS model, except that its primary resource unit is containers, not virtual machines (VMs) or bare metal servers.
In this article, you will learn:
How CaaS Works
CaaS provides capabilities that automate the deployment and hosting of containers across multiple cloud environments. CaaS does not rely on one code stack or language, which is why you can implement CaaS in multicloud and hybrid cloud environments.
The automation provided by CaaS can significantly increase the efficiency of your pipeline. Since many tasks are automated, development and IT staff gain more time and productivity increases. Additionally, automation can speed up processes and ensure the ecosystem remains consistently up-to-date.
CaaS vs PaaS, IaaS, and FaaS
Let’s review the differences between containers as a service and other popular cloud computing models.
Caas vs. PaaS
Platform as a Service (PaaS) involves third parties providing a combined platform, including both hardware and software. The PaaS model allows end users to develop, manage and run their own applications, while the platform provider manages the infrastructure. In addition to storage and other computing resources, providers typically offer a set of tools for application development, testing, and deployment.
CaaS differs from PaaS in that it is a lower-level service that only offers a specific infrastructure component—a container. CaaS services may provide development services and tooling like CI/CD release management, which brings them closer to a PaaS model.
Caas vs. IaaS
Infrastructure as a Service (IaaS) provides raw computing resources such as servers, storage, and networks in the public cloud. It allows organizations to scale up resources without upfront expenditure, and with low risk and overhead.
CaaS differs from IaaS in that it provides an abstraction layer above the raw hardware resources. IaaS services like Amazon EC2 provide compute instances, which are essentially computers with operating systems running in the public cloud. CaaS services run and manage containers on top of these virtual machines, or in the case of services like Azure Container Instances, allow users to run containers directly on bare metal resources.
Caas vs. FaaS
Function as a Service (FaaS), also known as serverless computing, is suitable for users who need to run a specific function or component of an application, without managing servers. With FaaS, the service provider automatically manages physical hardware, virtual machines, and other infrastructure, while the user only provides code and pays per duration or number of executions.
CaaS differs from FaaS in that it does provide direct access to infrastructure—users can configure and manage containers. However, some CaaS services, like Amazon Fargate, use a serverless deployment model to provide container services while abstracting servers from users, making them more similar to a FaaS model.
Top Container as a Service Providers
Amazon Elastic Container Service (AWS ECS)
Amazon Elastic Container Service (ECS) is a cloud service that manages and scales containers, without requiring developers to configure or set up the environment. ECS runs applications on groups of servers called clusters, allowing developers to control them through API calls.
ECS evaluates and monitors CPU and memory utilization to determine optimal container deployment on hardware resources. It closely integrates with AWS Elastic Load Balancing (AWS ELB), Elastic Block Store (AWS EBS) for persistent storage, and Identity and Access Management (AWS IAM) for access control.
Related content: read our guide to AWS containers ›
Azure Container Instances
Azure Container Instance (ACI) is a service that allows developers to deploy containers directly on Microsoft Azure hardware without the need to provision or manage infrastructure. There is no need to configure and manage virtual machines and implement container orchestration platforms, such as Kubernetes.
You can easily launch new containers through the Azure portal or Azure CLI, and Microsoft automatically configures and scales your underlying compute resources. The service supports both Linux and Windows containers. ACI supports the use of images from public container registries like Docker Hub and Azure Container Registry, and can be integrated with private registries.
Google Cloud Run
Google Cloud Run is a fully managed serverless platform that allows you to run Docker container images as stateless, auto-scaling HTTP services. Unlike pure serverless platforms, Cloud Run can do more than run small functions in a limited interface. You can use containers to run complex applications with multiple endpoints.
Google Cloud Run automatically scales the number of container instances in response to incoming requests from each application. It also provides a concurrency setting that specifies the maximum number of requests a particular container instance can handle.