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Sebastian Rieger 4 months ago
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  1. 168
      kubernetes-example/kubectl-intro.md
  2. 20
      kubernetes-example/nginx.yml
  3. 16
      kubernetes-example/service.yml

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kubernetes-example/kubectl-intro.md

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

20
kubernetes-example/nginx.yml

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apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
namespace: web-test
spec:
selector:
matchLabels:
app: nginx-deployment
replicas: 3 # tells deployment to run 3 pods matching the template
template:
metadata:
labels:
app: nginx-deployment
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80

16
kubernetes-example/service.yml

@ -0,0 +1,16 @@
apiVersion: v1
kind: Service
metadata:
name: nginx-service
namespace: web-test
spec:
type: NodePort
selector:
app: nginx-deployment
ports:
# By default and for convenience, the `targetPort` is set to the same value as the `port` field.
- port: 80
targetPort: 80
# Optional field
# By default and for convenience, the Kubernetes control plane will allocate a port from a range (default: 30000-32767)
nodePort: 30007
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