Kubernetes kubeadm setup
- workflow
kubectl: kubernetes commandline tool
- kubectl is the commandline to communicate with k8s cluster.
- kubectl tool needs a configuration file (kubeconfig), general location of configuration is
~/.kube/config - Setup auto-completion Refer Here
Atomic unit of k8s = Pod
- K8s creates pods and container runs in the Pod
- Pod can have one or more containers
- Each Pod in k8s gets a unique ipaddress
- For multi container pods, the communication between containers in the same pod will be on localhost (127.0.0.1)
- To run any application in k8s we have to create a Pod
K8s ways of working
- For k8s everything is object. The objects are exposed over api. we can find out all the resources we can create in a cluster by executing a simple command
kubectl api-resources
- kubectl hint: we can get the information of any object
kubectl get <resource-type>
kubectl get <resource-type> -o wide
* to understand what are options in a resource
kubectl explain <resource-type>
- To view a particular object
kubectl describe <resource-type> <resource-name>
- Creating objects in k8s can be done in two ways
- imperative:
- We construct a command line to create a object
- Refer Here
- declarative
- We express what we want (desired state) in a yaml file
- this helps in automation, reusable, consistent
- imperative:
