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Container-as-a-Service (CaaS, or Containers-as-a-Service) is a type of platform that provides managed services for hosting and operating containerized applications.
The specific types of managed services that CaaS platforms provide can vary, but common components include:
- Host infrastructure: Most CaaS solutions provide servers on which containerized applications can run. CaaS providers provision and manage those servers as part of the offering.
- Container management software: CaaS platforms usually include built-in, preconfigured container orchestration or management tooling. Many of them use Kubernetes for this purpose, but some rely on custom, proprietary orchestration services.
- Registries: Some CaaS platforms offer cloud-based container registries, making it easy for users to store and distribute container images without having to set up their own registries.
- Security tools: CaaS platforms may provide certain types of container security tools, such as container image scanners. While such tools can help in meeting basic container security needs, they are typically not sufficient on their own to cover all aspects of container security.
Keep reading for a breakdown of how Container-as-a-Service platforms work as well as tips on when it does and doesn’t make sense to use this type of cloud container service.
Examples of Cloud Container Services
All of the major public cloud providers offer at least one Container-as-a-Service solution, such as:
- Amazon Elastic Container Service (ECS), a CaaS platform powered by a proprietary cloud container service.
- Amazon Elastic Kubernetes Service, a CaaS platform powered by Kubernetes.
- Azure Kubernetes Service, the Kubernetes-based cloud container service from Azure.
- Google Kubernetes Engine, a managed Kubernetes service hosted on Google Cloud Platform.
In general, all of the major cloud-based CaaS platforms work the same. The major differences between them lie in whether they use Kubernetes or a different orchestration technology to provide container management, and which other public cloud services they integrate with. Unsurprisingly, the CaaS offerings from each public cloud provider are designed to integrate well with that public cloud’s other services; they support few, if any, integrations with competing public clouds.
On-Premises CaaS Examples
It’s also possible to deploy some container management platforms, such as Rancher and OpenShift, to create on-premises CaaS environments.
Although you wouldn’t get fully managed host infrastructure in that case (instead, you’d need to provide your own infrastructure), on-premises CaaS platforms provide simplified deployment processes.
They also usually feature native integrations between various types of container services and tools, making it easier to get a container hosting environment up and running.
Common Use Cases for CaaS
There are several reasons to consider using CaaS.
The main reason to use Containers-as-a-Service is that it saves time and effort. Without CaaS, you’d have to set up host infrastructure, container management software, container registries, and any other tooling you need to operate containers on your own.
You’d also have to integrate each of those components together to create a streamlined environment for running your apps. And you’d have to manage all of the components on an ongoing basis by ensuring that they are up-to-date and handling any outages or performance issues on your own.
In contrast, with CaaS, most of the setup and management work associated with running containerized apps gets outsourced to a CaaS provider.
Again, the exact services that you get from CaaS can vary from one offering to another, but in general, all CaaS platforms significantly reduce the effort that goes into running containerized apps. By extension, they reduce the size of the IT team necessary to support containers.
In some cases, CaaS can reduce the overall cost of running containers, for several reasons:
- Lower setup and management requirements translate to lower staffing costs associated with operating containers.
- CaaS providers may be able to deliver container hosting infrastructure at a lower cost than businesses could manage on their own.
- Because CaaS solutions can scale up and down easily, they allow customers to avoid wasting money on infrastructure they don’t need.
If you have a large infrastructure at your disposal, as well as a team capable of setting up and managing containers on its own, CaaS may not save you money. But CaaS can be financially expedient for organizations that need a simple, scalable way of running containerized apps.
Experimentation with Containers
CaaS solutions are convenient for use cases where engineers want to experiment with containers. For example, a business that is still validating a migration to container-based infrastructure could use a CaaS to create a test environment where it can vet container-based versions of its apps before setting up a production environment.
Since CaaS is easy to deploy, it makes it simple to test out containers.
CaaS vs. PaaS, IaaS, and FaaS
Container-as-a-Service solutions are similar in a few respects to other types of *aaS cloud services, but they’re ultimately distinct.
CaaS vs. PaaS
A Platform-as-a-Service (PaaS) is a platform that integrates software development tooling with managed application host infrastructure. CaaS is similar in that it also (usually) includes managed hosting infrastructure.
However, CaaS doesn’t typically encompass software development tools. You could create your own CI/CD pipeline and push applications from it into a CaaS environment in order to create something similar to a PaaS, but that’s not the same as using a PaaS where the development tools and hosting infrastructure are baked into a single, integrated offering.
CaaS vs. IaaS
Infrastructure-as-a-Service (IaaS) is a type of cloud service that provides access to infrastructure, such as virtual machine instances, on demand.
IaaS resources are usually included within CaaS platforms, where IaaS provides the hosting infrastructure for containers. But IaaS is only one component of CaaS.
CaaS vs. FaaS
Functions-as-a-Service (FaaS), is a cloud-based solution for operating serverless functions on demand using fully managed host infrastructure. Many FaaS services make it possible to deploy containerized apps (in addition to other types of application deployment formats), so they are similar in a key way to CaaS.
That said, FaaS caters only to application deployment. It doesn’t provide the extensive orchestration or container image management capabilities of CaaS. FaaS makes sense if you just want to deploy individual applications quickly, but CaaS is better if you need broader control over how your applications operate.
Limitations of CaaS
Like most types of managed services, CaaS is subject to the limitation that users get less control over how their applications are hosted and run. When you use a CaaS, you are restricted to the container hosting, deployment, and management options that your CaaS platform supports.
You would have more flexibility if you set up your own container hosting environment from scratch using the infrastructure and software tools of your choice.
In a similar vein, CaaS may restrict the visibility you can achieve into your container environment. You may not be able to collect as many metrics or access as many log files as you could if you had full control over the hardware and software that powers your containers.
Container-as-a-Service solutions are a great way to reduce the complexity of deploying containerized applications. The tradeoff is that you’ll have less control over your container hosting stack.
And remember that whether you use a CaaS or not, you’ll need solutions in place for managing the many security challenges that arise when you deploy containers.