168 lines
3.6 KiB
Markdown
168 lines
3.6 KiB
Markdown
# Introduction to kubectl
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## Prerequisites
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For using this you must install the following tools:
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- Python
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- Pip
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- Kubectl
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- Openstack-Client
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### Python
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Install python and pip for your OS, if it is not installed. This is already done at the NetLab PCs.
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### Installing kubectl and arkade
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Run this in a **bash** terminal to download arkade and install kubectl:
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For windows you can use e.g. the **Git Bash** terminal.
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```bash
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curl -sLS https://dl.get-arkade.dev | sh
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arkade get kubectl
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# To load the path to the binary
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export PATH=$PATH:$HOME/.arkade/bin/
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```
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With arkade you can also install other tools: ```arkade get``` to see all possibilities.
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### Openstack Client
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To install the Openstack client and the magnum package:
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If you are using Windows, you must start the bash terminal with **Administrator** privileges!
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```bash
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pip3 install openstackclient python-magnumclient
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# Download the Openstack RC File from your Openstack account
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# Load the file
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source {USERNAME}-openrc.sh
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```
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### Download the kubeconfig
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Download the kubeconfig file for your cluster from OpenStack.
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```bash
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# Before using this, check if Openstack RC File is loaded!
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openstack coe cluster config {CLUSTER_NAME}
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# Then run the given command in terminal
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export ...
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# Now you are able to run kubectl commands at your Kubernetes cluster
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```
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## Deployment of the needed description in kubernetes
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These are two approaches to create the description in Kubernetes:
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```bash
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# create a namespace
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kubectl create namespace web-test
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# Then choose one of the following ways:
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# (1) Create the description
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kubectl create -f nginx.yml -f service.yml
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# (2) Create or update descriptions if existing
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kubectl apply -f nginx.yml -f service.yml
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```
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## To show it is working
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Here are some useful commands:
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```bash
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# show nodes
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kubectl get nodes
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# show pods for our namespace
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kubectl get -n web-test pods
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# show deployments for our namespace
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kubectl get -n web-test deployment
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# show services for our namespace
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kubectl get -n web-test service
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# show logs of deployed nginx instances
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kubectl logs -n web-test deployment/nginx-deployment
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```
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## Scaling up and down
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```bash
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# scale up instances to 5
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kubectl scale -n web-test deployment/nginx-deployment --replicas=5
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# scale down instances again to 3
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kubectl scale -n web-test deployment/nginx-deployment --replicas=3
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```
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## To see it is working in the browser ;)
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The nginx instances are reachable at the floating ips of the **node**-instances at port **30007** in our case.
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## Many other things can be done ;)
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- Autoscaling
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- Detailled Service functions (LoadBalancer, ...)
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- Dashboard
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- FaaS Setup ;)
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- ...
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## Appendix
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### Nginx description
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*nginx.yml:*
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```yml
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: nginx-deployment
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namespace: web-test
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spec:
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selector:
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matchLabels:
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app: nginx-deployment
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replicas: 3 # tells deployment to run 3 pods matching the template
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template:
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metadata:
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labels:
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app: nginx-deployment
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spec:
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containers:
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- name: nginx
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image: nginx:latest
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ports:
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- containerPort: 80
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```
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### Nginx service description
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*service.yml:*
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```yml
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apiVersion: v1
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kind: Service
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metadata:
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name: nginx-service
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namespace: web-test
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spec:
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type: NodePort
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selector:
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app: nginx-deployment
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ports:
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# By default and for convenience, the `targetPort` is set to the same value as the `port` field.
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- port: 80
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targetPort: 80
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# Optional field
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# By default and for convenience, the Kubernetes control plane will allocate a port from a range (default: 30000-32767)
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nodePort: 30007
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``` |