Relationship Between Docker and Kubernetes
Can you explain the relationship between Docker and Kubernetes? If I were to host on DigitalOcean, would I host Docker inside Kubernetes?
Let’s break down the relationship between Docker and Kubernetes, and how they can be used together on a platform like DigitalOcean.
Docker
- Purpose: Docker is a containerization platform that allows you to package your application into containers. These containers are lightweight, portable, and provide isolation from other processes running on the same host.
- Functionality: You can create, manage, and deploy individual containers using Docker.
Kubernetes (K8s)
- Purpose: Kubernetes is an orchestration tool designed to automate the deployment, scaling, management, and maintenance of containerized applications across multiple hosts.
- Functionality: It helps manage clusters of nodes (servers) where your containers run. This includes features like automatic deployment rollouts/rollbacks, self-healing (restarting failed nodes), and resource allocation/management.
Using Docker with Kubernetes
When you use Kubernetes with Docker:
- You typically package your application into a Docker image.
- Then you define how these images should be deployed in terms of desired state using YAML or JSON files in Kubernetes.
- Kubernetes manages these images by creating pods (the smallest execution unit in K8s), which contain one or more containers based on those images.
Hosting on DigitalOcean
If you choose to host on DigitalOcean:
Option A: Host Only with Docker
You can simply deploy your application as individual containers directly onto Droplets without using an orchestrator like Kubernetes. This approach is straightforward but lacks automation for scaling or managing multiple instances efficiently.
Option B: Host Inside a Managed Platform Like App Platform
DigitalOcean offers App Platform which simplifies deploying web apps without needing direct interaction with underlying infrastructure like VMs or Containers manually.
Option C: Use Managed Services for Both
For more complex setups where scalability is important:
- Deploy your applications packaged as Docker images inside a managed service such as DigitalOcean’s Managed Databases for databases if needed.
- Use DigitalOcean’s App Platform which supports deploying containerized apps directly without manual orchestration setup required by full-fledged K8s environments.
However, if you need full control over orchestration features such as rolling updates or node management:
- You would typically set up a cluster using DigitalOcean’s Managed Kubernetes Service which automates much of the setup process but still gives you access to advanced features provided by K8s.
Summary
- If simplicity is key and your app doesn’t require complex scaling/scaling back operations—using just Docker might suffice.
- If automation of deployments/scaling across multiple servers becomes necessary—using both Docker for packaging applications and K8s for orchestration makes sense.
For most scalable solutions that involve managing many instances across different servers efficiently—combining both technologies within an environment managed by services offered by cloud providers like DigitalOcean provides optimal flexibility and reliability.
DigitalOcean offers a managed Kubernetes service (DOKS) that is beginner-friendly and cost-effective. Click here for a step-by-step guide to help you deploy three containers (SuiteCRM, n8n, and Supabase) on a DigitalOcean Kubernetes cluster.