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

  1. Install minikube

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

  2. 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/

  3. 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/

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

  5. ensure default kvm network up

     virsh net-autostart default
     virsh net-start default

  6. start

     minikube start --vm-driver=kvm2 

  7. verify that minikube is running

     virsh list

  8. 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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