Kubernetes workshop (EN)

e-kurz

Kurzem Vás provede Jiří Snopek

IT lektor a konzultant, RHCA. Vede tým zaměřený na vývoj i provoz webových a mobilních aplikací.

Základní info

Description

Build your own cluster to running cloud-native applications with Kubernetes. Our workshop covers it all using engaging examples and activities.

Kubernetes is an open source platform for managing container workloads and services that facilitates declarative configuration and automation. It has a large, rapidly growing ecosystem. Kubernetes services, support, and tools are widely available.

Goals

Participants will learn the following concepts and skills:

Containers and the concept of an orchestra
Basic concepts of Kubernetes
Advanced kubectl
Kubernetes cluster management
Networking, storage and security for Kubernetes
Helm charts and tables

Target

The course is designed for sysadmins, DevOps, systems engineers, and others who need an introduction to containers and Kubernetes.

Basic Kubernetes concepts

API server,
- control plane, worker nodes
Kubernetes API objects, API groups
Kubernetes YAML manifests and objects
Basic object kinds
- Pods, ConfigMaps, Secrets
- Services, labels and annotations
- Deployments, StatefulSets
- Namespaces
- Ingresses
- Custom Resources
Kubernetes controllers
- scheduler, ...

TASKS:

connect to K8S server
create objects in the API server
list node objects
ensure labels and annotations

Advanced kubectl
Use kubectl parameters for custom scripting and object processing

connection to remote K8s cluster
--output and --template formats
--selector
--dry-run=

TASKS:

Use multiple `kubeconfig`s
Use kubectl filtering and outputs
Compare `.spec` and `.status` sections of k8s object

Application Deployment with apps/v1
Using `Deployments`, `DaemonSets`, `StatefulSets` for application deployment and rollout.

Why do we need selectors?
`Deployment` and relation to `ReplicaSet`
What is `revisionHistoryLimit` and what can go wrong?
multiple `rolloutStategies` and their usage
What is `ownerReference` used for?

TASKS:

Place `Deployment`, modify it and watch the results
Check `revisionHistoryLimit` quirks.
Compare `Recreate` and `RollingUpdate` priorities. Tune RollingUpdate strategy
Inspect `ownerReference`

Exposing container services to the outer world
Exposing pods to services using pod labels. Explore multiple service types.
Ingresses and CertificateManager expose service with HTTP/HTTPS protocol.
Services:

Difference on ClusterIP vs headless services
Using ExternalName service for service discovery

Ingresses:

How ingresses works
How can we use CertificateManager to get certificates using ACME protocol

TASKS (Services):

Expose pods using service..
Inspect the exposed service with DNS lookups.
Create headless service and compare it to ClusterIP one
Inspect Service Endpoints
Create LoadBalancer service (on cloud only)

TASKS (Ingresses):

Expose service to the world on HTTP
Configure CertificateManager
Use CertificateManager to get LetsEncrypt certificate

Pod Resource Limits
Using `resourceLimits`, soft and hard limits, pod `QualityofService` classes.
What can go wrong with resource limits?
TASKS:

Place resourceLimits on the objects
Explore what happens when pod exceeds the limits.

Pod statuses and lifecycle
Pods can have multiple states and advanced initialization

using `containers` and `initContainers`
pod probes - `startupProbe`, `livenessProbe` and `readinessProbe`
use `lifecycle` hooks - `preStop` and `postStart`
Use `terminationMessagePath`

TASKS:

Use initContainers, use `preStop` and `postStart` hooks.
Explore `livenessProbe` and `readinessProbe` within a service.

Pod scheduling and affinities
Some pods can be started with `podPriority`. How it can be used?
Pods can be scheduled to be located on specific nodes with affinities.
TASKS:

Create a PriorityClass and apply it to a node.
Schedule a pod to the specific nodes with `nodeAffinity`.
Schedule multiple pods to one node with `podAdffinity`
Explore pod with `podAntiAffinity`

Deployment with Kustomize
What is `kustomize` used for and what problems can `kustomize` solve for us?
TASKS:

Use kustomize to deploy multiple instances of one application
Inspect kustomize generated manifests.

Demo:

Using kustomize with ArgoCD.

Helm charts
Using Helm for deploying applications consisting of multiple manifests. Which tasks Helm solves for us?
TASKS:

Download chart from registry
Inspect the chart
Deploy the chart to a release.
Customize the chart `values` and redeploy. Inspect the deployed objects.
Optionally: create a custom chart.

Container storage
Implementing persistent storage with `PersistentVolume` and `PersistentVolumeClaim` objects.
TASKS:

Inspect existing StorageClasses
Create a new PVC
Deploy Pod with PVC.
Explore PV modes.

To be discussed?

Jobs
Cronjobs
ServiceAccounts and their permissions
Secret management
Log management
Event management

Prerequisites

Docker and Kubernetes basics.

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