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Kubernetes Beginnings

You have containerized applications but you need to manage them! Kubernetes can do that for you.

Let's see what Kubernetes offers us:

  1. Kubernetes is an open-source tool for automating deployment, scaling, and operation of containerized applications (originated from Google's Borg)
  2. It is designed for large-scale management, enhancing efficiency through faster releases and self-healing capabilities
  3. Operates as a distributed system, forming clusters from physical or virtual machines either on-premises or in the cloud
  4. Uses scheduling algorithms for container allocation and adapts itself as needed
  5. It has a modular design that supports multiple container runtimes, not only Docker
  6. Key Features:
    • Declarative configuration
    • Horizontal scaling
    • Secret management
    • Service discovery and load balancing
    • Linux and Windows container support
    • Stateful application support
    • Persistent volumes
    • Log collection
    • CPU/Memory quotas
    • Batch processing
    • RBAC (Role-based Access Control)
  7. Alternatives to Kubernetes:
    • DC/OS
    • Docker Swarm
    • Amazon ECS

How to Deploy Kubernetes​

Deployment Methods​

  1. Single-node clusters for development and testing can be set up using:

    • Docker for Mac/Windows
    • minikube
    • kubeadm

  2. Kubernetes in Docker (kind) is recommended for creating ephemeral clusters in continuous integration pipelines

  3. Multi-node clusters are advised for production to benefit from horizontal scaling and fault tolerance

Single-node vs. Multi-node Clusters​

  • Single-node clusters: Simpler and suitable for learning, development, and testing
  • Multi-node clusters: Offer resilience and scalability for production workloads

Managed Kubernetes Services​

  • Services like Amazon EKS, Azure AKS, and Google GKE simplify Kubernetes deployment but may have delayed updates
  • Tools like kubespray, kops, and kubeadm offer more customization and control

Considerations for Deployment​

  • Level of control
  • Cloud provider investments
  • Need for enterprise support
  • Concerns about vendor lock-in

Hybrid Cloud and Container Types​

Kubernetes supports hybrid cloud environments and both Linux and Windows containers, offering flexibility in deployment.

Kubernetes Architecture​

For detailed information about Kubernetes architecture, see Kubernetes Architecture.

Installing Kubernetes​

Using Kubeadm on EC2​

Installing a Kubernetes cluster using Kubeadm on EC2 provides insight into how control plane and worker node components work internally, including the join phase mechanism to connect master and worker nodes.

Using Minikube​

Minikube is great for local development. Behind the scenes, Minikube works like Kubeadm and performs the join phase mechanism.

Minikube Commands​

# Bootstrap a single node cluster with LTS Kubernetes
minikube start

# Specify a specific Kubernetes version
minikube start --kubernetes-version=v1.31.1

# Use a specific driver (if you have virtualization drivers)
minikube start --driver=virtualbox

# Check the status
minikube status

# Stop the minikube cluster
minikube stop

# Delete minikube and its VM completely
minikube delete

Accessing Kubernetes Cluster​

A Kubernetes cluster can be accessed via:

  • kubectl - CLI tool
  • Kubernetes Dashboard - GUI
  • APIs - Programming or CLI