Ansible and Kubernetes are two of the most popular tools for automation and infrastructure management. But they serve different purposes and have their own strengths. This in-depth guide examines how Ansible and Kubernetes compare across various factors to help you decide which one is best suited for your needs.
Overview
Ansible is a configuration management and automation tool used to automate IT infrastructure setup, app deployment, configuration management, and more across private and public clouds.
Kubernetes is a container orchestration platform designed for automating containerized application deployment, scaling, and management across clusters of hosts.
While Ansible focuses more on automating IT tasks, Kubernetes specializes in container orchestration. But they can work together as part of an organization‘s automation stack.
Key Differences
Here‘s a quick look at some key differences between the two tools:
| Parameter | Ansible | Kubernetes |
|---|---|---|
| Type | Configuration management/automation tool | Container orchestration platform |
| Architecture | Agentless | Master-nodes architecture |
| Configuration | YAML playbooks | YAML/JSON manifests |
| Scaling focus | Small to large infrastructure | Large-scale containerized apps |
| Learning curve | Moderate | Moderate to steep |
Next, let‘s explore their features, architecture and other aspects in more detail.
Ansible
Ansible is an open source automation and configuration management tool developed by Red Hat. It uses YAML playbooks to automate and manage IT infrastructure components like networks, servers, containers, and applications.
Features
- Agentless – Uses OpenSSH and WinRM for remote execution without requiring agents on target hosts
- Idempotence – Can run tasks repeatedly while producing the same outcome
- Modular – Provides over 750 modules for various functionality like cloud, databases, commands etc. Users can also create custom modules
- Extensible – Allows extending core functionality via plugins
- Secure – Leverages SSH for secure connections and uses YAML for human readable configs
Architecture
Ansible works by establishing SSH connections from the control node to managed hosts for executing tasks defined in playbooks:
- Control Node – Machine with Ansible installed. Manages playbook runs on managed hosts
- Inventory – List of managed hosts, can be grouped by attributes
- Modules – Self-contained programs executed on managed hosts
- Plugins – Extend Ansible functionality
- Playbooks – YAML files defining automation tasks sent to managed hosts
- Managed Hosts – Machines being automated via Ansible
How Ansible Works
Ansible automates tasks on managed hosts by following this sequence:
- Establishes SSH connection from control node to managed host
- Sends relevant modules defined in playbooks to execute tasks
- Removes modules once tasks complete for security
- Provides output of automation results for monitoring
By leveraging YAML playbooks and roles, Ansible makes it simple to define infrastructure as code and consistently replicate it across environments.
Benefits
- Easy to learn syntax
- Agentless and secure
- Powerful modules and plugins
- Idempotent
- Facilitates infrastructure-as-code
- Vendor neutral
Ansible empowers DevOps teams to automate everything from cloud provisioning to app deployments and configuration management.
Kubernetes
Originally created by Google based on their internal container management systems and later donated to CNCF, Kubernetes has become the industry standard for managing containerized workloads and services.
Features
- Portability – Consistent environment for on-prem and cloud
- Autoscaling – Scale container instances based on demand
- Service discovery – Automatically assign container network names/locations
- Load balancing – Distribute network traffic across containers
- Rolling updates – Incrementally update apps with no downtime
- Monitoring – Track resource usage and container health
Architecture
Kubernetes follows a master-node architecture consisting of components like:
- API Server – Front-end for user control planes
- etcd – Key value store for cluster data
- Controller Manager – Ensures desired state matches actual state
- Scheduler – Assigns containers to nodes
- Kubelet – Agent that starts/stops containers
- Container Runtime – Software for running containers (Docker, containerd etc.)
- Nodes – Workers that run containerized apps
- Pods – One or more containers share resources
- Services – Network endpoint allowing communication between pods
How Kubernetes Works
Here is the high-level flow for running apps on Kubernetes:
- Package app code into container images
- Create manifests that describe desired cluster state
- Submit manifests to Kubernetes API server
- Kubernetes components cooperate to reach desired state
- Kubernetes manages infrastructure and app lifecycles
By taking care of critical concerns like scaling, updates, networking and monitoring, Kubernetes frees up developers to focus on writing code.
Benefits
- Simplifies app deployment and management
- Enables portability across environments
- Automates scalability and high availability
- Provides advanced networking constructs
- Extensible and pluggable architecture
With its robust architecture and thriving ecosystem, Kubernetes has become the standard for container orchestration.
Feature Comparison
Here is a detailed feature comparison between Ansible and Kubernetes:
| Feature | Ansible | Kubernetes |
|---|---|---|
| Configuration format | YAML playbooks | YAML/JSON manifests |
| Architecture | Agentless | Master-nodes |
| Communication | SSH, WinRM | TLS, HTTPS |
| Scalability | Small to large infra | Optimized for large scale |
| Automation capabilities | Broad IT automation | specialized for containers |
| Abstraction | Low-level | Higher-level constructs |
| Learning curve | Moderate | Steeper |
Additional Ansible strengths:
- Broad automation of servers, networks, cloud etc. beyond just containers
- Simpler YAML syntax and agentless architecture
- Powerful for configuration drift management
- Vast library of ready modules for functionality
Additional Kubernetes strengths:
- Purpose-built for container lifecycle management
- Advanced controllers for self-healing and autoscaling
- Rich load balancing, networking and security features
- Can leverage hosted Kubernetes services from cloud vendors
- Pluggable architecture allows easy extensibility
Integration and Use Cases
Despite their differences, Ansible and Kubernetes can work together quite well:
- Provisioning – Ansible helps rapidly provision Kubernetes infrastructure
- Configuration – Ansible manages configs for Kubernetes components
- Deployment – Ansible deploys apps on Kubernetes clusters
- Security – Ansible handles certs, secrets, RBAC for Kubernetes
Here are some common use cases for each tool:
Ansible use cases
- Server and infrastructure provisioning
- Multi-tier application deployments
- Automating IT processes like backups
- Configuration management for consistency
- Orchestrating updates across systems
Kubernetes use cases
- Containerized application deployments
- Cloud-native and microservices architectures
- Automating container lifecycles
- Achieving portability across environments
- Edge and IoT deployments
As you can see, Ansible excels at broad IT automation tasks while Kubernetes focuses specifically on container orchestration.
Learning Curve
- Ansible – Easy to get started with YAML playbooks. Moderate learning curve to master advanced features. Less complex overall.
- Kubernetes – Steeper learning curve as it involves grasping many concepts like pods, services, controllers etc. But managed services reduce complexity.
Ansible is simpler to pick up especially for automating infrastructure and apps. Kubernetes has a steeper curve but the payoff is automated container clusters.
Conclusion
Ansible and Kubernetes solve two different, but complementary problems in the automation space.
Ansible brings simple but powerful automation for provisioning, configuration and application deployment across on-prem and cloud environments.
Kubernetes is purpose-built for large scale container orchestration with advanced capabilities around networking, scaling, security and portability.
Understanding their core capabilities allows you to use Ansible and Kubernetes side-by-side as part of a comprehensive automation strategy:
- Use Ansible to provision, deploy and manage Kubernetes clusters
- Leverage Kubernetes to natively orchestrate containerized workloads at scale
- Combine them to enable infrastructure-as-code and cloud native application delivery
So don‘t look at it as Ansible vs Kubernetes. Look at how you can use them together to tame infrastructure complexity and deliver applications with speed, resilience and portability.
