Container orchestration platforms like Amazon ECS and Kubernetes have become essential tools for deploying and managing containerized applications at scale. But which one is the best choice for your needs? This in-depth comparison explores the key differences between these two leading orchestration systems.
What is Container Orchestration and Why Does it Matter?
Before diving into the specifics of ECS and Kubernetes, it helps to take a step back and understand what container orchestration is and why it’s important.
In a nutshell, container orchestration manages the lifecycles of containers. It allows you to coordinate and automate the deployment, scaling, networking and availability of containerized applications across clusters of hosts.
Without an orchestrator, running containers at scale and in production can become extremely complex:
- Deploying containerized apps requires manually configuring hosts
- Scaling up/down means adding or removing hosts by hand
- Failures can lead to outages without health monitoring
- Networking and service discovery must be handled manually
A container orchestration platform handles all of this complexity for you. It deploys containers based on your desired state, scales them, monitors health, manages networking/service discovery, and more. This automation is essential for running containerized apps seamlessly in production.
The two most widely used orchestrators today are Amazon ECS and Kubernetes (K8s). Let’s explore them in more detail.
Introducing Amazon ECS
Amazon Elastic Container Service (ECS) is a hosted container orchestration service created by AWS. ECS allows you to run and scale Docker containers on AWS infrastructure.
With ECS, you define the application containers you want to run and the compute requirements. ECS handles starting containers, distributing tasks across instances, monitoring health, and replacing failed containers.
Some key components and concepts in ECS:
- Clusters – Logical groupings of EC2 instances to run tasks on
- Task Definitions – Metadata in a JSON template for the containers to run
- Tasks – Instantiation of a task definition on a cluster
- Services – Configs enabling long-running tasks and auto-scaling
- Container Agent – Runs on each EC2 instance to start/stop tasks
With these building blocks, ECS deploys your containers onto infrastructure and handles the complexities of orchestrating and scaling your app.
Benefits of ECS
Some of the top advantages of using ECS include:
- Tight integration with other AWS services for monitoring, auto-scaling, load balancing, security, IAM roles etc.
- Simple console interface to get started quickly
- Fully managed service – AWS handles OS and Kubernetes patching/upgrades
- Works well for basic containerized applications on AWS infrastructure
Limitations of ECS
ECS does have some downsides to consider:
- Vendor lock-in to Amazon EC2 for infrastructure
- Less flexibility than Kubernetes in terms of customization
- Networking, storage and scaling not as robust as standalone Kubernetes
- Steep learning curve if adopting more advanced features
Overall, ECS is a solid option for running containerized applications on AWS, but does lack some of the extensibility of Kubernetes.
Kubernetes (K8s) is an open-source container orchestration system originally designed by Google. It has become the most widely used platform for deploying and managing containers at scale.
Kubernetes provides tools for deploying, scaling, networking, load balancing, logging and monitoring of containerized applications. It is designed to be highly extensible and portable across many infrastructure providers.
Some key components in Kubernetes include:
- Pods – Basic unit containing one or more containers
- Nodes – The virtual or physical machines Kubernetes runs on
- Deployments – Configuration for Pods and ReplicaSets
- ReplicaSets – Ensures desired number of Pods are running
- Services – Abstraction for accessing Pods from other Pods or external sources
- Ingress – Rules for external access to services running in the cluster
With these primitive building blocks, Kubernetes provides a highly flexible and automated way to manage containerized workloads.
Benefits of Kubernetes
Reasons why Kubernetes has become so widely adopted include:
- Open source with very active development community
- Write once, run anywhere architecture – can run on any infrastructure
- Highly flexible and extensible for complex use cases
- Powerful networking, storage and scaling capabilities
- Large ecosystem of tools and integrations
Limitations of Kubernetes
Kubernetes does pose some challenges for new adopters:
- Steep learning curve with many new concepts
- More complex to initially configure and manage
- Requires expertise in Kubernetes itself and supporting tools
- Overkill for simple containerized applications
Kubernetes provides immense power and flexibility, but also comes with complexity.
ECS vs Kubernetes: Key Feature Comparison
Now that we’ve introduced ECS and Kubernetes, let’s compare them across some key functionality every orchestrator provides:
- ECS uses Task Definitions and Services to declare container applications
- Kubernetes uses Pods, ReplicaSets, Deployments and other API resources
- ECS integrates with Elastic Load Balancing (ELB)
- Kubernetes has native Service abstractions and supports Ingress controllers
- ECS storage limited to EBS volumes
- Kubernetes supports many storage options including EBS, EFS, StorageOS, Rook and more
- ECS ties autoscaling to CloudWatch rules
- Kubernetes has native autoscaling capabilities like the Horizontal Pod Autoscaler
- ECS supports rolling updates via task definition changes
- Kubernetes allows rolling updates via Deployment configuration changes
- ECS integrates with CloudWatch for container monitoring
- Kubernetes provides robust visibility with metrics-server, cAdvisor and more
- ECS integrates with IAM for access control
- Kubernetes has native Role Based Access Control (RBAC)
Overall, Kubernetes provides greater breadth and depth of orchestration features, while ECS offers tighter AWS integration.
Real World Use Cases
The types of applications and environments you plan to run will impact whether ECS or Kubernetes is better suited.
ECS is a good option for:
- Simple containerized applications
- Apps that need to leverage other AWS services
- Running smaller workloads on AWS
- Users looking for a fast ramp up on containers
Kubernetes excels for:
- Large and complex containerized applications
- Microservices architectures
- Hybrid cloud or multi-cloud deployments
- Advanced use cases like machine learning, data processing pipelines, etc
- Organizations seeking portability across infrastructure
If your goal is to get containers running on AWS quickly and easily, ECS is likely the best choice. Need a full-featured, flexible and portable container platform? Go with Kubernetes.
There are no software license costs for either ECS or Kubernetes since both are free to use. However, there are infrastructure and management costs to consider.
With ECS, you only pay for the EC2 resources consumed to run containers. There are no additional management fees.
Kubernetes itself is open source, so also free. But you will need to provision and manage the underlying VMs or cloud instances. This operational overhead does add cost and complexity vs ECS.
The fully managed nature of ECS makes it simpler and cheaper to operate at smaller scales. But Kubernetes can be more cost effective at very large scales with optimized infrastructure utilization.
Also consider the cost of expertise – Kubernetes will require engineers knowledgeable in the platform which can be more expensive than ECS skills.
There is no one-size-fits-all answer to the ECS vs Kubernetes choice. The factors below should steer you towards the best decision:
- If you just need basic containerization on AWS, choose ECS for simplicity
- If you want an enterprise-grade container platform, Kubernetes is more robust
- Existing internal skills with either platform should be heavily considered
- Applications tightly coupled to AWS services may prefer ECS
- Workloads needing portability across cloud providers lean towards Kubernetes
Most organizations will likely benefit from adopting both ECS and Kubernetes. ECS for simple use cases, Kubernetes for complex ones. This provides the best of both worlds.
I hope this comprehensive comparison helps provide clarity on which container orchestration platform aligns to your requirements. Leveraging the right solution will enable you to deploy and operate containerized applications seamlessly at scale.