> For the complete documentation index, see [llms.txt](https://lib.rjo.me/newlib/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lib.rjo.me/newlib/operating-systems/linux/kubernetes.md).

# Kubernetes

## Installing Virtualbox

[virtualbox](https://computingforgeeks.com/install-virtualbox-on-kali-linux-linux-mint/) or the summary:

```
#!/bin/bash
wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -
wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -
echo "deb [arch=amd64] http://download.virtualbox.org/virtualbox/debian bionic contrib" | sudo tee /etc/apt/sources.list.d/virtualbox.list
sudo apt-get update
sudo apt update
sudo apt install linux-headers-$(uname -r) dkms
sudo apt-get install virtualbox-6.0
cd ~/
wget https://download.virtualbox.org/virtualbox/6.0.0/Oracle_VM_VirtualBox_Extension_Pack-6.0.0.vbox-extpack
```

## AWS Kubernetes EKS

The first command creates a new context entry in `~/.kube/config` the second command displays the available contexts, then the third command changes the contexts to the one provided context-name from the output of the second command. The fourth command displays the now active context.

```
aws eks --region us-east-1 update-kubeconfig --name $(StackName)
kubectl config get-contexts
kubectl config use-context __Name from get-contexts__
kubectl config current-context
```

Alternatively a less manual approach. (Ust the `-r` flag in `jq` to get the string without quotes) Make sure to use the aws profile/IAM User that created the cluster or assign the create-cluster privileges to your user.

```
FIRSTCLUSTER=$(aws eks list-clusters | jq -r '."clusters"[]') 
aws eks --region us-east-1 update-kubeconfig --name $FIRSTCLUSTER
THISCONTEXT=${/kubectl config get-contexts | grep \* | awk '{ print $2 }'}
kubectl config use-context $THISCONTEXT
```

## Kubernetes Objects

### Deployment

Deployments create Pods from Images. Create Deployments from deployment yaml files, like

```
kubectl create -f deployment.yaml
```

To allow images being pulled from AWS ECR in minikube [docs](https://minikube.sigs.k8s.io/docs/tutorials/configuring_creds_for_aws_ecr/)

```
minikube addons configure registry-creds
minikube addons enable registry-creds
```

The creds have to be referenced in the yaml like this:

```
imagePullSecrets:
  - name: awsecr-cred
containers:
    image: 123456789123.dkr.ecr.us-east-1.amazonaws.com/flaskpy:latest
    ports:
```

Next services

### Services

Services are used to expose Deployments internally or publicly

#### NodePort

Nodeports are used to expose a Service on a Node outside to local Kubernetes cluster. This can be used for Development on Minikube.

#### ClusterIP

Cluster IP Services are used for Deployments that need to talk to other Services inside Kubernetes but not the outside world

#### Loadbalancer

Loadbalancer Services are only available on supported Cloud Service Provicers. A Loadbalancer Service creates an object in the Cloud e.g. an AWS Loadbalancer to expose a Kubernetes Deployment publicly through AWS Route53.