Kubernetes Docker cluster manager

Azure/Kubernetes
Notes: https://gitlab.com/snippets/1813194
Interacting with running pods - https://kubernetes.io/docs/reference/kubectl/cheatsheet/#interacting-with-running-pods

2022 k3s / k3d

k8s/k3s/k3d
Simplest local k8s install, can run cluster as docker containers to simulate multiple nodes, even works on pi

201903 minikube

Install using curl
open host fw for port 8443 admint to vm
sudo minikube start --vm-driver=kvm2
helm

201810 microk8s snap https://github.com/ubuntu/microk8s

ubuntu laptop - $/!\$ not a big snap fan -

sudo snap install microk8s --classic
microk8s.kubectl get all --all-namespaces
microk8s.kubectl get no
microk8s.enable dns dashboard
watch microk8s.kubectl get all --all

sudo snap alias microk8s.kubectl kubectl

2019 Load tls certificate into kubernetes secrets

check the validity of certificate by

openssl x509 -in fullchain.pem -text -noout | grep -A 2 'Validity'

Load cert with kubectl

kubectl create secret tls wildcard-mine-tls --key privkey.pem --cert fullchain.pem

201804

minikube

Install minikube

curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin/

for kvm add kvm2 driver https://github.com/kubernetes/minikube/blob/master/docs/drivers.md#kvm2-driver

curl -LO https://storage.googleapis.com/minikube/releases/latest/docker-machine-driver-kvm2 && chmod +x docker-machine-driver-kvm2 && sudo mv docker-machine-driver-kvm2 /usr/local/bin/

kubectl to manage things.

curl -Lo kubectl https://storage.googleapis.com/kubernetes-release/release/v1.10.0/bin/linux/amd64/kubectl && chmod +x kubectl && sudo mv kubectl /usr/local/bin/

ensure current user belongs to libvirtd and kvm installed sudo apt install libvirt-bin qemu-kvm

ensure default kvm network up

virsh net-autostart default
virsh net-start default

start
```
minikube start --vm-driver=kvm2 
```
verify that minikube is running
```
virsh list
```
Test with examples from https://kubernetes.io/docs/getting-started-guides/minikube/#installation

201704

Add google apt-key

curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

Add to apt sources.list

cat <<EOF > /etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF

echo "deb http://apt.kubernetes.io/ kubernetes-trusty main" >> /etc/apt/sources.list.d/kubernetes.list

install packages

sudo apt-get install -y docker.io kubelet kubeadm kubectl kubernetes-cni
sudo systemctl enable docker.service

Got a error for docker certificate, had to delete it to get the docker deamon to start
- error
  - ```
  level=fatal msg="Error creating cluster component ...Bla...Bla...Bla... certificate expired.
```
- fix rm /var/lib/docker/swarm/certificates/swarm-node.*
setup kubernetes (k8s) master node
- ```
sudo kubeadm init
```
- error in pre-flight checks
```
DOCKER_GRAPH_DRIVER: btrfs
```
- fix, edit the /etc/docker/deamon.conf and add devicemapper option, remember "," after options.
  - ```
  "storage-driver": "devicemapper",
```

Success for kubeadm init

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run (as a regular user):

  sudo cp /etc/kubernetes/admin.conf $HOME/
  sudo chown $(id -u):$(id -g) $HOME/admin.conf
  export KUBECONFIG=$HOME/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  http://kubernetes.io/docs/admin/addons/

You can now join any number of machines by running the following on each node
as root:

  kubeadm join --token 030871.9354eb2226c8b23b 10.0.2.15:6443

Ubuntu 14.04 trusy - does not have a full set of kubernetes packages

Install from source
1. sudo apt install git -y
2. git clone https://github.com/kubernetes/kubernetes.git
3. cd kubernetes
4. ./build/run.sh make cross

...

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