VielenDanke / kubernetes-demo

Demo Kubernetes (Main abstractions) application.

Kubernetes main abstractions

Preparation

Ingress

To enable ingress:

• Docker desktop - https://kubernetes.github.io/ingress-nginx/deploy/#docker-for-mac
  • Using kubectl - kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.3.0/deploy/static/provider/cloud/deploy.yaml
  • Using helm - helm upgrade --install ingress-nginx ingress-nginx \ --repo https://kubernetes.github.io/ingress-nginx \ --namespace ingress-nginx --create-namespace
• Minikube - minikube addons enable ingress

Repository application

If you want to test application inside repository - do not forget to:

• Span all preparation containers - kubectl apply -f kubernetes/preparation
• Build application - docker build -t $registry/$image_name:$tag $directory
• Push application - docker push -t (tag from previous step)
• Change image section in deployment.yaml file to new $registry/$image_name:$tag

Docker registry

To access docker registry:

• Register on https://hub.docker.com/
• Now your image tag will look like $your_login/$image_name:$tag

To create your own registry:

• See https://docs.docker.com/registry/deploying/

To use minikube registry:

• See https://minikube.sigs.k8s.io/docs/handbook/registry/

To install image directly to minikube:

• minikube image build -t $image:$tag -f $dockerfile_path $dockerfile_directory
  • minikube image build -t books:minikube -f Dockerfile . (Example)

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Application

Application with cluster IP and ingress

Step-by-step instruction - Application with Cluster IP service and Ingress

• kubectl apply -f kubernetes/examples/application-cluster-ip
  • Do not forget to turn Ingress addon on if you are using minikube
• Add IP of your cluster to /etc/hosts file (Windows C:\Windows\System32\drivers\etc\hosts):
• Check if it is working: curl -v ingress.local

Application with nodePort

Step-by-step instruction - Application with NodePort service

• kubectl apply -f kubernetes/examples/application-nodeport
• Check if it is working: curl $(minikube ip):30007 | curl localhost:30007
  • Be aware, on OS (Windows, Mac with Minikube) abstraction won't be reachable. Don't be afraid, it is working.
  • Access NodePort on minikube (https://minikube.sigs.k8s.io/docs/handbook/accessing/)

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Folder structure

• kubernetes/application - application abstractions
• kubernetes/configuration - configuration abstractions
• kubernetes/network - network abstractions
• kubernetes/preparation - abstractions for presentation
• kubernetes/job - abstractions for job
• kubernetes/examples - ready to deploy applications based on Nginx image

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Kubernetes network

• https://www.youtube.com/c/%D0%90%D1%80%D1%82%D1%83%D1%80%D0%9A%D1%80%D1%8E%D0%BA%D0%BE%D0%B2

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Kubernetes commands

Main commands:

Short names:

• configmap – cm
• pod – po
• services – svc
• ingress – ing

Work with context:

All contexts are placed in file: ~/.kube/config

• kubectl config get-contexts – find all available contexts
• kubect config use-context $-context_name- – use the context for kubectl

To edit resource:

• kubectl edit $resource -n $namespace $resource_name
  • Example: kubectl edit secrets -n trends plutus-tls

To describe resource:

• kubectl describe $resource -n $namespace $resource_name
  • Example: kubectl describe pod -n trends plutus-integ-asdasd-123we

To download resource:

• kubectl get $resource -n $namespace $resource_name -o $format some.$format – download resource as file with specific format (json, yaml).
  • Example: kubectl get cm -n trends coolmap -o yaml some.yaml

To get resource:

• kubectl get $resource -n $namespace – all resources in the namespace
• kubectl get $resource --all-namespaces – all resource in all namespaces

Pod:

• kubectl exec -n $namespace -it $pod_name - - /bin/sh – working inside a container
• kubectl logs -n $namespace $pod_name – get pod logs

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Minikube commands

• minikube node add - add another node for minikube
• minikube addons list - all addons for minikube
• minikube addons enable $addon_name - enable any addon for minikube
• minikube image build -t $tag $directory - build image directly to minikube
• minikube mount $from:$to - mount directory to minikube
• minikube ip - show ip address of minikube
• minikube —help - help description of minikube commands