Taints and Toleration - kubernetes

Question

im practicing with kubernetes taints , i have tainted my node and than make a deploy like this:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.15.4
ports:
- containerPort: 80
tolerations:
- key: "test"
operator: "Equal"
value: "blue"
effect: "NoSchedule"
kubectl describe nodes knode2 :
Name: knode2
Roles: <none>
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=knode2
kubernetes.io/os=linux
testing=test
Annotations: kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
node.alpha.kubernetes.io/ttl: 0
projectcalico.org/IPv4Address: **********
projectcalico.org/IPv4IPIPTunnelAddr: ********
volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp: Tue, 27 Oct 2020 17:23:47 +0200
Taints: test=blue:NoSchedule
but when i deploy this yaml file the pods are not going only to that tainted node.
Why is that?

Answer 1

Taints and tolerations work together to ensure that pods are not scheduled onto inappropriate nodes. That's exactly opposite of what you intend to do.
You can constrain a Pod to only be able to run on particular Node(s), or to prefer to run on particular nodes using NodeSelector or NodeAffinity.
NodeSelector example
apiVersion: v1
kind: Pod
metadata:
name: nginx
labels:
env: test
spec:
containers:
- name: nginx
image: nginx
imagePullPolicy: IfNotPresent
nodeSelector:
disktype: ssd
Node affinity is conceptually similar to nodeSelector -- it allows you to constrain which nodes your pod is eligible to be scheduled on, based on labels on the node.