Sebastian Rieger
4 years ago
3 changed files with 204 additions and 0 deletions
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168kubernetes-example/kubectl-intro.md
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20kubernetes-example/nginx.yml
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16kubernetes-example/service.yml
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# 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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``` |
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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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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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