Kubernetes for Beginners: An Introductory Guide

Kubernetes for Beginners: An Introductory Guide

• 1.
  What is Kubernetes? A Beginners’Guide
• 2.
  Both are essentiallystructures for storing and running applications. ● Virtual Machines (VMs) - Isolated at hardware level, higher resource usage. ● Containers - Slightly less isolated, leaner and faster. ○ Docker has ~95% market share in containerisation technology. Virtualisation Technologies - VMs vs. Containers
• 3.
  Virtualisation Technologies -VMs vs. Containers
• 4.
  ● Because containersare so lean, you can have a huge number of them on a single server. They allow large monolithic applications to be split into many microservices. ● Each microservice has its own container & controls one feature of the application. ○ Benefit: This is an efficient use of resources & can save on hosting costs compared to VMs. ○ Problem: How do you manage, rollout, rollback, maintain and repair such a large number of containers? ● The solution: Kubernetes You can have 1000’s of containers on a server
• 5.
  ● Kubernetes (K8S)is an open source software tool for managing containerised workloads. ● It operates at the container (not hardware) level to automate the deployment, scaling and management of applications. ● K8s works alongside a containerisation tool, like Docker. So if containers are the ‘ingredients’ of an application, then K8S would be the ‘chef’. ● As well as managing individual containers, K8s can also manage clusters. ○ A cluster is a series of servers connected to run containers. ○ K8s can scale up to 5,000 servers and 150,000 pods in a single cluster. ○ A pod is a group of containers that share resources, a network and can communicate with one another. Kubernetes: Definition
• 6.
  How Does KubernetesWork? 1. Worker Nodes (slave) - This is where containers are deployed. These nodes contain: a. Multiple pods b. Docker engine c. Any add-ons e.g. DNS d. Kubelet - this is an important component as it carries out the instructions from the master node. 2. Master Node (master) - This controls the deployment. This node contains: a. API server - this receives inputs from the User Interface (UI) or Command Line Interface (CLI). b. Controller - uses information from the API to drive the application from its current state towards the desired state provided. c. Scheduler d. Etcd - handles configuration management, service discovery etc. Kubernetes has a master-slave architecture:
• 7.
  Kubernetes Architecture To makethe last slide easier to visualise, here is a diagram of the architecture: Nodes 1-n (in purple) are the worker nodes.
• 8.
  ● Remembering thespecific components and their roles isn’t important here. ● The architecture has just been outlined to give some background on how Kubernetes is able to orchestrate containers at scale. ● Whilst initially the idea of Kubernetes sounds quite simple, seeing the architecture shows that is is actually fairly complex to work with. ● This is why Bytemark want to offer a managed Kubernetes service - so our customers can get the benefits of Kubernetes without worrying about managing and maintaining everything themselves. Kubernetes Architecture
• 9.
  ● Self-healing ○ Clusterscan auto-restore from errors by rolling back to the last working version of software. This allows teams to ship quickly without the risk of breaking anything. ● High Availability ○ Clusters can be recreated on a working node to avoid downtime during server failure. ● Simplifys Maintenance ○ If a server needs to be rebooted, or the host OS needs updating, containers can be moved to another node whilst maintenance is carried out. ● Automatic Scaling ○ Uses information from user requests and CPU usage to increase or decrease the number of nodes running to match demand. ● Efficient ○ Automatically spins up any new containers on under-utilized nodes. Benefits of Kubernetes
• 10.
  There are sometimesmisconceptions about what Kubernetes can do. Kubernetes does not… ● Provide any comprehensive machine configuration. ● Provide a configuration language/system ● Dictate logging, monitoring or alerting solution ● Build your application ● Provide middleware, data-processing frameworks, databases, caches etc. BUT these components can run on Kubernetes Things Kubernetes does not do...
• 11.
  ANY QUESTIONS? ● Tolearn more about Kubernetes at Bytemark, contact sales@bytemark.co.uk