A PaaS is typically a suite of cloud-based applications that organizations can use to accomplish specific sets of tasks. PaaS is most often associated with software development tasks such as coding, testing, packaging and deployment. Because the PaaS provider handles all the software tool deployments, management and updating, organizations can shed those elements of their local infrastructure and support — ideally simplifying their IT environment.
A container is a type of virtual entity that enables an organization to run code, usually in the form of smaller applications or modular software components. Containers share a common OS and offer quick spin-up, launch and stop times, making containers fast and convenient for running virtualized, highly scalable and highly orchestrated enterprise workloads.
Containers often have a vital role in any PaaS. Consider that a PaaS might need to spawn software tools for users to work within, and a PaaS typically enables users to deploy applications such as web applications and custom services — whatever the PaaS users create.
However, those deployments need some underlying mechanism to provision and configure computing and storage resources for application deployment. Because PaaS providers don’t use human IT staff to handle all those deployment and scaling processes, the PaaS provider will opt for an efficient, highly automated infrastructure for such tasks.
In short, a PaaS typically uses containers for PaaS software deployments.
Thus, containers — such as those running on the Docker engine — are frequently considered to be a central building block, and even an enabler, of modern PaaS.
Containers aren’t limited to PaaS. Organizations often use containers in the local data centre for the exact same benefits; enabling users to easily deploy and spawn applications within containers. Local containers would also rely on an established service such as Docker, Apache Mesos or another container engine to support containers, while using an orchestration engine such as Kubernetes to automate many of the tasks involved with container deployment and management.
PaaS technology enables countless different types of platforms. Most platforms focus on activities such as software development and include a limited variety of deployment mechanisms designed to launch and host the applications created by the platform. Such deployment mechanisms often rely on containers to provide the underlying application deployment infrastructure.
But such use cases are relatively narrow, and the PaaS provider establishes the environment for any containers — such as the base OS. Today, an increasing number of platforms focus specifically on containers as deployment mechanisms in the form of containers as a service (CaaS). Thus, CaaS handles the automated deployment and hosting of containerized software. The CaaS provider supplies the infrastructure and engines needed to deploy, manage and monitor containers and the underlying deployment environment. In this context, CaaS is offered as a specific type or subset of PaaS.
Containers encapsulate application code but share an OS kernel.
The mechanisms used to create a CaaS offering can be virtually identical to those mechanisms used to support software deployments in containers through other types of PaaS. But CaaS expands the available options and potential sophistication of the container environment and can be a better fit for complex container environments, such as microservices applications, where each container deployed to a CaaS might encapsulate a different OS and other dependencies.
So, if the goal is to develop and deploy software, a PaaS might be the better choice. If the goal is to deploy and manage large numbers of containers in complex arrangements, CaaS might be better.
PaaS is attractive for many organizations because it can jumpstart and support a wide array of projects — an organization can jump in and access top-tier tools and resources without the cost or complexity involved in creating and maintaining those tools, resources and other infrastructure in-house. An organization can focus on their core business and competencies without supplying the underlying infrastructure. So, the benefits of PaaS include the following:
PaaS also presents a number of potential challenges and disadvantages organizations should consider, such as the following:
As with VMs, virtual containers have brought an array of benefits to organizations and application developers, such as the following:
But containers are far from perfect, and organizations that opt to work with containers must contend with several disadvantages, including the following:
The choice between PaaS and containers usually isn’t a deliberate one. Containers are a typical deployment avenue for many PaaS offerings — container use might be unavoidable when selecting a PaaS. Fortunately, most PaaS providers have made great strides in simplifying and automating their container infrastructure. A PaaS using containers is often the fastest and easiest choice when speed and convenience are high priorities for business users.
If control and oversight are the highest priorities for an organization, it might make more sense to forego a PaaS and build a container infrastructure in the local data centre. This requires IT support with significant expertise in container technologies, starting with the underlying container engine, such as Docker, and automation and orchestration tools, such as Kubernetes. In-house containers are undoubtedly more complex and costly but might be necessary when business needs and goals dictate.
CaaS presents a third choice, enabling organizations to use container services for large and complex container deployments while eliminating much of the infrastructure and software platforms involved in container support. CaaS can be a suitable choice when an organization needs the speed and scalability of PaaS, but the focus is on containers and container-based application deployments.
As always, it’s important for IT and business leaders to understand the needs, costs, reliability, availability, portability, features and functionality of all alternatives before making a commitment to any technology or provider.
Organizations can expect to see a tighter relationship between containers, clouds and cloud platforms (PaaS) in the years ahead. Consider some of the following current relationships:
