⭐ What is Kubernetes?
Orchestration Platform: Kubernetes is an advanced orchestration platform.
Container Management: It's used to efficiently manage containers.
Google's Brainchild: Originally developed by Google using the Go language.
Open Source: Google donated Kubernetes to the CNCF (Cloud Native Computing Foundation).
Inception Year: The first version of K8S was released in 2015.
Open & Free: Kubernetes is open-source and free to use.
📦 Kubernetes internally uses Docker to manage containers
⭐ Docker Swarm vs. Kubernetes
| Aspect | Docker Swarm | Kubernetes (K8s) |
| Orchestration | Basic orchestration for Docker containers. | Advanced container orchestration platform. |
| Auto Scaling | Lacks auto-scaling; scaling is manual. | Supports auto-scaling for efficient scaling. |
| Production Ready | Suitable for smaller deployments. | Highly recommended for production deployments. |
| Node Management | Simpler node management. | Offers robust node management capabilities. |
| Compatibility | Works well for Docker-based setups. | Supports various container runtimes and formats. |
| Community Support | Smaller community compared to K8s. | Large and active community with extensive support. |
| Ease of Use | Easier to set up and manage for smaller projects. | More complex, but highly configurable. |
Docker Swarm Limitations: Docker Swarm lacks auto-scaling, requiring manual intervention.
K8S Auto Scaling: Kubernetes supports auto-scaling for streamlined operations.
Production-Ready: Kubernetes is highly recommended for production deployments.
Swarm Replacement: Kubernetes is considered a replacement for Docker Swarm.
🚀 Auto Scaling: Adjust container counts dynamically based on incoming requests.
⭐ What is a Cluster?
Server Grouping: A cluster is a group of interconnected servers.
Cluster Components: It consists of master and worker nodes.
Task Delegation: DevOps engineers delegate tasks to the Kubernetes master node.
Master's Role: The master node manages worker nodes and schedules tasks.
High Availability: Achieve high availability through cluster setups.
⭐ Kubernetes Architecture
Control Plane Components:
Control Plane: Also known as the master node or manager node.
API Server: Handles incoming requests.
Scheduler: Schedules tasks.
Control Manager: Manages tasks.
ETCD: Internal database for task info.
Worker Nodes:
Pods: Basic units for running containers.
Containers: Runtime instances of applications.
Kubelet: Worker node agent.
Kube Proxy: Manages network communication.
Docker Runtime: Required for running containers.
Communicating with the K8S Control Plane
Kubectl: The command-line interface (CLI) tool for K8S.
Web UI Dashboard: A web-based graphical interface for Kubernetes.
⭐ Detailed Components of Kubernetes Architecture
Control Plane (Master Node):
- Responsible for handling all Kubernetes-related work.
Worker Nodes:
- Responsible for executing our applications as Pods.
API Server:
- Handles incoming requests from the Control Plane for deploying applications.
Etcd:
An internal database within the Kubernetes cluster.
The API Server stores requests/tasks info in Etcd.
Scheduler:
Responsible for scheduling pending tasks available in Etcd.
Decides on which worker node a task should execute.
Communicates with Kubelet for task placement.
Kubelet:
Acts as a worker node agent.
Maintains all information related to Worker Nodes.
Controller-Manager:
Manages task execution on worker nodes.
Ensures tasks run as expected.
Kube-Proxy:
Provides networking for Kubernetes cluster communication.
Facilitates communication between the Master Node and Worker Nodes.
Docker Engine:
Required to run containers.
Containers are created and managed on Worker Nodes.
Container:
- A runtime instance of our application.
Pod:
The smallest building block in Kubernetes for running containers.
Docker containers run inside Pods.
⭐ Setting Up Kubernetes: Your Path to Mastery
1. Self-Managed Cluster (Create Your Own Cluster)
a) Minikube (Single Node Cluster)
b) Kubeadm (Multi-Node Cluster)
2. Provider-Managed Cluster (Cloud Provider-Managed Clusters):
a) AWS EKS (Amazon Web Services Elastic Kubernetes Service)
b) Azure AKS (Azure Kubernetes Service)
c) GCP GKE (Google Cloud Platform Google Kubernetes Engine)
These are the initial steps on your captivating Kubernetes journey. The choice between self-management and the provider's gentle embrace hinges on your unique needs, expertise, and the degree of mastery you wish to achieve. Self-management empowers you with control, albeit with greater effort, while the provider-managed path offers ease at a cost, making each option a part of your orchestration symphony.