TaintTolerations.txt

# syntax to taint node 
k taint node node-name key=value:taint-effect
>> there are 3 taint-effect
a. NoSchedule
b. PreferNoSchedule
c. NoExecute

e.g 
k taint nodes node1 app:blue:NoSchedule

#Tolerations - pods
>> pod-definition.yaml
apiVerison: v1
kind: Pod
metadata: 
  name: myapp-pod
spec:
  containers:
    - name: nginx-container
       image: nginx
  tolerations:
    - key: "app"
      operator: "Equal"
      value: "blue"
      effect: NoSchedule


#Label
kubectl label node node01 color=blue

#Taints 
 kubectl describe node node01 | grep -i taints
 kubectl taint nodes node01 spray=mortein:NoSchedule



	
# cmd to view default enabled admission Controllers
kube-apiserver -h | grep enable-admission-plugins

# tain-tolerations syntax
kubectl taint node node-name key=vlaue:taint-effect

#here type of taint-effect
NoSchedule
PreferNoSchedule
NoExecute

# example to apply taint on node
kubectl taint nodes node1 app=blue:NoSchedule

# example to remove tainet on node
kubectl taint node node1 blue:NoSchedule-

# pod-with-tai n-tolerations.yaml
apiVersion: v1
kind: Pod
metadata: 
	name: myapp-pod
spec:
	containers:
		- name: nginx-container
		  image: nginx
	tolerations:
		- key: "app"
		  operator: "Equal"
		  value: "blue"
		  effect: "NoSchedule"
		  
# on master node bydefault NoSchedule taint will be get applied
$ kubectl describe node kubemaster | grep taint

# node selector 

first label your node
kubectl label nodes node-name label-key=label-value
example
kubectl label nodes node-1 size=Large

# pod-definition-node-selector.yaml

apiVerison: v1
kind: Pod
metadata:
	name: myapp-pod
spec:
	containers:
		- name: data-processor
		  image: data-processor
	nodeSelector:
		size: Large

# with NodeSelector we cannot provide 
- Large or Medium 
- NOT small 
so we have to use node affinity

# Node affinity
Types of node Affinity
- Available
requiredDuringSchedulingIgnoredDuringExecution
preferredDuringSchedulingIgnoredDuringExecution

- Planned 
RequiredDuringSchedulingRequiredDuringExecution


kubect create deployment blue --image=nginx --replicas=3
kubectl describe node node1 | grep taints

./script-name.sh
sh script-name.sh
bash script-name.sh


# replicaset-definition.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
	name: simple-webapp
	labels: 
		app: App1
		function: Front-end
spec:
	replicas: 3
	selector:
		matchLabels:
			app: App1
	template:
		metadata:
			labels: 
				app: App1
			function: Front-end
		spec: 
			containers: 
				- name: simple-webapp
				  image: simple-webapp