What is Kubernetes and Why Seek an Alternative?
Kubernetes is an open source container orchestration platform developed by Google. It helps manage distributed clusters of containers, often used for microservices and other distributed applications. Kubernetes is highly resilient and supports zero downtime, rollback, scaling, and container self-healing.
What are some of the challenges causing organizations to seek an alternative?
- Kubernetes can be overkill—while very powerful, and suitable for massive scale deployments, Kubernetes can be overkill for applications that do not require high scale or a distributed architecture.
Learn more in our guide to Kubernetes architecture ›
- Kubernetes is complex—it has a steep learning curve, even for developers and DevOps specialists, not to mention for less technical roles. However, the huge popularity of Kubernetes makes it essential to learn for many technical roles today.
Learn more in our guide to Kubernetes in production ›
- Difficult transition—migrating existing applications to Kubernetes can be difficult. In many cases, specific components or the entire architecture must be refactored, and applications need to be rebuilt using cloud native principles.
- High total cost of ownership—Kubernetes is an open source project, but it has several hidden costs. Beyond the high cost of deploying and operating Kubernetes, it also requires a large-scale computing environment to run. By settling for simpler deployment alternatives, an organization will have much simpler, cheaper hosting options.
In this article, you will learn about these Kubernetes alternatives:
Understanding the Options: Container Services, Kubernetes Services, and Lightweight Orchestrators
Kubernetes is extremely powerful, yet difficult to learn and operate. This has given rise to an industry that aims to make Kubernetes easier to adopt and use.
The primary options you can choose instead of Kubernetes are:
- Container as a Service (CaaS)—services like AWS Fargate and Azure Container Instances, which allow you to manage containers at scale without the complex orchestration capabilities provided by Kubernetes.
- Managed kubernetes services—including Google Kubernetes Engine (GKE) and Amazon Elastic Kubernetes Service (EKS), which let you run managed, hosted Kubernetes clusters. These services remove much of the complexity of deploying, upgrading and maintaining Kubernetes, but still require expertise to manage.
- PaaS using Kubernetes—several providers, such as OpenShift Container Platform and Rancher, offer complete cloud computing platforms, which have Kubernetes at their core, but offer simpler operation and built-in capabilities like security and networking.
- Lightweight container orchestrators—Kubernetes is the most popular container orchestrator, but is definitely not the only one. Docker Swarm and Nomad are two examples of capable, mature orchestrators, which are much less complex to use and maintain than Kubernetes
Kubernetes Alternatives: Container as a Service (CaaS)
1. AWS Fargate
AWS Fargate is a serverless compute engine used in conjunction with Amazon Elastic Container Service (ECS). You can use it to run containers without managing servers or clusters of Amazon EC2 instances. Fargate has a flexible computing model, which does not require you to select an instance type or directly configure your cluster. It scales up transparently and you pay according to the CPU and memory resources you actually use.
Because Fargate does not have orchestration capabilities, it is suitable for standalone services, simple microservices applications, or distributed systems like batch processing that do not require close interaction between components.
2. Azure Container Instances
Azure Container Instances (ACI) is a service that allows developers to deploy containers directly in Microsoft Azure public cloud without the need to provision or manage infrastructure.
This service supports both Linux and Windows containers. It bypasses the need to configure and manage virtual machines, or implement container orchestration platforms like Kubernetes. You can easily launch new containers through the Azure portal or the Azure CLI, and Microsoft automatically configures and scales the underlying compute resources.
ACI supports the use of images from public container registries, like Docker Hub, and the Azure Container Registry.
3. Google Cloud Run
Google Cloud Run is a fully managed serverless platform that lets you run Docker container images as stateless, auto-scaling HTTP services. Unlike serverless platforms like Google Cloud Functions or AWS Lambda, Cloud Run goes beyond running small functions with a limited interface. It can run complex applications with multiple endpoints.
Cloud Cloud Run automatically scales the number of container instances according to the incoming requests to each application. It also offers a concurrency setting, which specifies the maximum number of requests a particular container instance can handle.
Kubernetes Alternatives: Managed Kubernetes Services
4. Google Kubernetes Engine (GKE)
Google is the original developer of Kubernetes, and is still heavily involved in its development. It was also the first to launch a managed Kubernetes service—the Google Kubernetes Engine. GKE is considered to be one of the most mature Kubernetes services on the market.
GKE runs recent versions of Kubernetes and is committed to automating Kubernetes management tasks. It integrates with other Google Cloud services to provide access control, security, and other capabilities. Google also provides Anthos, which lets you run GKE on-premises and on other public clouds, including AWS.
5. Amazon Elastic Kubernetes Service (EKS)
AWS EKS is a service that simplifies and automates deployment and management of Kubernetes clusters. It is available on Amazon infrastructure (with both EC2 and Fargate as deployment options), and can also be used to manage Kubernetes on-premises. It runs a recent version of open source Kubernetes, and is compatible with the full ecosystem of Kubernetes tools.
EKS fully manages the Kubernetes control plane and scales master nodes as needed, ensuring high availability by deploying across multiple availability zones. It manages a wide range of Kubernetes setup and maintenance tasks, including replacement of unhealthy instances and Kubernetes updates.
6. Azure Kubernetes Service
Azure Kubernetes Service (AKS) makes it easy to deploy managed Kubernetes clusters to Azure. AKS shifts the responsibility for managing the Kubernetes control plane to Azure, reducing management complexity and operational overhead.
AKS handles ongoing tasks like health monitoring and maintenance, and manages Kubernetes hosts in Azure VMs. Unlike the comparable services on AWS and Google Cloud, AKS bills only for Kubernetes worker nodes, offering master nodes and cluster management free of charge.
Kubernetes Alternatives: PaaS Platforms
7. Openshift Container Platform
Red Hat’s OpenShift Container Platform is a hybrid cloud platform that allows organizations to build and scale containerized applications. It is based on Docker-style Linux containers, Kubernetes, and Red Hat Enterprise Linux (RHEL).
As a complete distributed application platform, Openshift Container Platform goes beyond the capabilities of plain Kubernetes. It offers standardized container support with Docker’s Red Hat API, container orchestration, scheduling, container networking, and simplified deployment capabilities.
Rancher is an open source platform that runs containers in production across multiple environments—on-premise and on any public cloud. It captures computing resources from public or private clouds and seamlessly deploys Kubernetes resources on them.
Rancher’s key features include cross-host networks, container load balancing, persistent storage services, multi-tenancy, user management, multi-cloud management, and built-in security for Kubernetes clusters.
Kubernetes Alternatives: Lightweight Orchestrators
9. Docker Swarm
Docker is a platform for building containerized applications. Docker Swarm is a feature that lets you cluster and schedule Docker Engines. You can use this feature by enabling the Swarm mode in Docker.
Swarm is a native feature of Docker. Once it is enabled you can start using the Docker Engine CLI to create a swarm and orchestrate your cluster. You can use Swam, to manually and automatically monitor and scale your clusters.
Docker Swarm mode offers a decentralized design that ensures Docker Engines can handle specializations at runtime. It lets you deploy both manager and worker nodes, and essentially build a swarm using a single disk image.
There are many more features for orchestration, including load balancing, service discovery, rolling updates, and multi-host networking. Security is provided through TLS mutual authentication and encryption which is enforced by each node in the swarm.
Nomad, developed by HashiCorp, is a flexible container orchestrator that allows organizations to deploy and manage both containers and legacy applications, with the same workflow for both. It places a strong focus on ease of use.
Nomad lets developers deploy applications in a declarative approach, using infrastructure as code (IaC), and run workloads like Docker, non-container applications, microservices, and batch applications side by side.
Key features include device plugins, GPU support, multi-region federation, multi-cloud management, scalability up to clusters of 10,000 nodes or more, and integration with the HashiCorp ecosystem, including Terraform, Consul, and Vault.