-como saber si el OS tiene k8 instalado



If using your own equipment you will have to disable swap on every node, and ensure there is only one network interface.
Multiple interfaces are supported but require extra configuration.  There may be other requirements which will 
be shown as warnings or errors when using the kubeadm command.




Before install container runtime engine: crio, etc

-----------------------------------------------------installing k8s 1.23 
 
---- version 1 repo manager ubuntu, kubeadm=1.23.1-00 kubelet=1.23.1-00 kubectl
 
1) Add a new repo for kubernetes
root@cp:~# vim /etc/apt/sources.list.d/kubernetes.list
   deb  http://apt.kubernetes.io/  kubernetes-xenial  main
 
1.1 Add a GPG key for the packages
root@cp:~# curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -

root@cp:~# apt-get update

Install the software
root@cp:~# apt-get install -y kubeadm=1.23.1-00 kubelet=1.23.1-00 kubectl=1.23.1-00

   posibles errores:
         Some packages could not be installed. This may mean that you have
		requested an impossible situation or if you are using the unstable
		distribution that some required packages have not yet been created
		or been moved out of Incoming.
		The following information may help to resolve the situation:
		
		The following packages have unmet dependencies:
		 kubeadm : Depends: kubernetes-cni (>= 0.8.7)
		 kubelet : Depends: kubernetes-cni (>= 0.8.7)

      solutions
        root@node010:~# apt-cache search kubernetes-cni
		kubelet - Kubernetes Node Agent
		kubernetes-cni - Kubernetes CNI
		root@node010:~# apt-get install kubernetes-cni


root@cp:~# apt-mark hold kubelet kubeadm kubectl

root@node010:~# kubectl version
root@node010:~# kubeadm version
root@node010:~# kubelet --version


NOTE: 
  - Hasta aqui los mismo pasos para instalar k8s en control plane y workers.
  - Los sig pasos solo aplican para control planes 
      

2)use Calico as a network plugin
root@cp:~# wget https://docs.projectcalico.org/manifests/calico.yaml
root@cp:~# less calico.yaml 
  search
    name: CALICO_IPV4POOL_CIDR
    value:"192.168.0.0/16"

2.1 update hosts
root@cp:~# vim /etc/hosts
<the ip address of control plane node> k8scp    #<-- Add this line


3)Create a configuration file for the cluster. For crio kubeadm-crio.yaml. Inside tarball from linux fundation course
   wget https://training.linuxfoundation.org/cm/LFS258/LFS258_V2021-09-20_SOLUTIONS.tar.xz --user=LFtraining --password=Penguin2014
   wget https://training.linuxfoundation.org/cm/LFS258/LFS258_V2022-03-22_SOLUTIONS.tar.xz --user=LFtraining --password=Penguin2014
   
   Find th file and copy to home(del root)


for crio use kubeadm-crio.yaml, update the following accordingly:
...
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: 1.23.1               #<-- Use the word stable for newest version
controlPlaneEndpoint: "k8scp:6443"      #<-- Use the node alias not the IP
networking:
    podSubnet: 192.168.0.0/16           #<-- Match the IP range from the Calico config file
    
    
4)Initialize the control plane(cp)
root@cp:# kubeadm init --config=kubeadm-crio.yaml --upload-certs  | tee kubeadm-init.out   # Save output for future review

Success messages:


			Your Kubernetes control-plane has initialized successfully!
			
			To start using your cluster, you need to run the following as a regular user:
			
			  mkdir -p $HOME/.kube
			  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
			  sudo chown $(id -u):$(id -g) $HOME/.kube/config
			
			Alternatively, if you are the root user, you can run:
			
			  export KUBECONFIG=/etc/kubernetes/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:
			  https://kubernetes.io/docs/concepts/cluster-administration/addons/
			
			You can now join any number of the control-plane node running the following command on each as root:
			
			  kubeadm join k8scp:6443 --token abcdef.0123456789abcdef \
			        --discovery-token-ca-cert-hash sha256:6cff953cb5b537a8eef9c32535dbe3db9deca2884f8000ac4e59c9c11854c85b \
			        --control-plane --certificate-key 733803415367b636ee688ae7b2cbda2b61f1d838366f148092efd8f329cec114
			
			Please note that the certificate-key gives access to cluster sensitive data, keep it secret!
			As a safeguard, uploaded-certs will be deleted in two hours; If necessary, you can use
			"kubeadm init phase upload-certs --upload-certs" to reload certs afterward.
			
			Then you can join any number of worker nodes by running the following on each as root:
			
			kubeadm join k8scp:6443 --token abcdef.0123456789abcdef \
			        --discovery-token-ca-cert-hash sha256:6cff953cb5b537a8eef9c32535dbe3db9deca2884f8000ac4e59c9c11854c85b


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

		student@cp:~$	  mkdir -p $HOME/.kube
		student@cp:~$	  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
		student@cp:~$	  sudo chown $(id -u):$(id -g) $HOME/.kube/config
			
			Alternatively, if you are the root user, you can run:
			
			  export KUBECONFIG=/etc/kubernetes/admin.conf



6) Apply the network plugin configuration to your cluster. 

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

--para calico
   student@cp:$ kubectl apply -f calico.yaml




7)enable bash auto-completion

student@cp:$ sudo apt-get install bash-completion -y
student@cp:$ source <(kubectl completion bash)              
student@cp:$ echo "source <(kubectl completion bash)" >> $HOME/.bashrc