kubeadm installation
- kubeadm cluster setup Refer Here
kubeadm init --pod-network-cidr=10.244.0.0/16 --cri-socket unix:///var/run/cri-dockerd.sock
- Once the command is succesful you would get and output
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/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 172.31.9.186:6443 --token oc7nyd.g36rl6lycyk15ywl \
--discovery-token-ca-cert-hash sha256:ef3f2b626d6168b4d2cbb64a044285def92423aa312f37405d49adb31a356815
- To run kubernetes as a non root user on control plane
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
- The network of the kuberentes is CNI is implemented by many providers Refer Here
- When the manual installation of k8s is done, most of the organizations prefer flannel Refer Here
kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml
- Now login into the node 1 and become a root user and then execute
kubeadm join 172.31.9.186:6443 --token oc7nyd.g36rl6lycyk15ywl \
--discovery-token-ca-cert-hash sha256:ef3f2b626d6168b4d2cbb64a044285def92423aa312f37405d49adb31a356815
- Now perform the same on the node 2 by executing the same command shown below as a root user
kubeadm join 172.31.9.186:6443 --token oc7nyd.g36rl6lycyk15ywl \
--discovery-token-ca-cert-hash sha256:ef3f2b626d6168b4d2cbb64a044285def92423aa312f37405d49adb31a356815
- Now login into master/control plane and execute
kubectl get nodes
Kubernetes playground
- Login into kubernetes playground Refer Here and create two nodes
- On the node which you choose as control plane/master execute the following commands
You can bootstrap a cluster as follows:
1. Initializes cluster master node:
kubeadm init --apiserver-advertise-address $(hostname -i) --pod-network-cidr 10.5.0.0/16
2. Initialize cluster networking:
kubectl apply -f https://raw.githubusercontent.com/cloudnativelabs/kube-router/master/daemonset/kubeadm-kuberouter.yaml
* Now join the node2 to cluster and once its done, login into control plane and execute the below commands
Kubectl cheatsheet
- Refer Here
- Set autocompletion
kubectl
- This is official k8s client
- Checking cluster status
kubectl version
- To check whether your cluster is healthy
kubectl get componentstatuses
- kubectl has two primary commands to obtain information
- get
- describe
kube-proxy
- kube proxy is responsibe for routing network traffic in the k8s cluster. To do this job, the proxy should be present on all the nodes in the cluster
kuberenetes DNS
- kuberentes also runs a DNS server, which provides naming and discovery for the services in k8s cluster
- There is also a k8s service that performs load balancing for the DNS server
Note: As of now we are using kubectl from the control plane i.e we login into control plane and use kubectl, when we start using k8s as a service i.e on cloud we would setup kubectl on any machine from where we want to deploy applications.
