10 Questions
What is the primary function of the API server in a Kubernetes cluster?
To validate and configure data for API objects
What is the purpose of etcd in a Kubernetes cluster?
To store cluster data
What is the role of the Kubelet in a Kubernetes cluster?
To ensure containers are running in a pod
What is the primary function of the container runtime in a Kubernetes cluster?
To run containers
What is the purpose of controllers in a Kubernetes cluster?
To ensure the desired cluster state
What is the primary function of the scheduler in a Kubernetes cluster?
To assign nodes to newly created pods
What type of environment can Kubernetes clusters run in?
Virtual, physical, cloud-based, and on-premises environments
What is a master node in a Kubernetes cluster?
A node that controls and manages worker nodes
What is the relationship between the API server and other components in a Kubernetes cluster?
The API server is the frontend to the cluster's shared state through which all other components interact
What is the role of Docker in a Kubernetes cluster?
As a container runtime
Study Notes
Containers and Orchestration
- Containers are needed to solve several challenges, such as compatibility and dependency problems, long setup times, and different Dev/Test/Prod environments.
- A container consists of an entire runtime environment: an application, its dependencies, libraries, and other binaries, and configuration files needed to run it, bundled into one package.
Containers vs Virtual Machines
- Containers run on top of the host OS kernel, whereas Virtual Machines run their own OS kernel.
- Containers share the host OS kernel, whereas Virtual Machines have their own OS kernel.
Docker Overview
- Docker is a container runtime that allows you to package, ship, and run applications in containers.
- Docker consists of:
- Docker daemon (dockerd) that listens for Docker API requests and manages Docker objects.
- Docker client (docker) that sends commands to dockerd.
- Docker registry that stores Docker images.
- Docker Hub, a public registry that anyone can use.
Containers Orchestration
- Containers orchestration is necessary to manage the lifecycle of containers, especially in large, dynamic environments.
- Orchestration automates the scheduling, deployment, networking, scaling, health monitoring, and management of containers.
- A use case for containers orchestration is when you have multiple applications running on a single server and need to scale, deploy, and manage them.
Limits of Containers without Orchestration
- Managing a small number of containers on a few hosts using Docker CLI is adequate, but falls short of automating complex deployments on multiple hosts.
Kubernetes
- Kubernetes is an open-source container orchestration engine for automating deployment, scaling, and management of containerized applications.
- Kubernetes architecture consists of:
- Node: a virtual or physical machine that runs containers.
- Cluster: a set of nodes that run containerized applications.
- Master Node: a node that controls and manages a set of worker nodes.
- API Server: validates and configures data for API objects.
- etcd: a consistent and highly-available key-value store used as Kubernetes' backing store.
- Kubelet: an agent that runs on each node and ensures containers are running in a pod.
- Container Runtime: software that runs containers, such as Docker, containerd, or CRI-O.
- Controller: control loops that watch the state of the cluster and make changes where needed.
- Scheduler: selects a node for newly created pods to run on.
Learn the basics of containerization, differences between containers and VMs, and the importance of orchestration. Understand Kubernetes architecture and its role in container orchestration.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
