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:NoSchedulebut when i deploy this yaml file the pods are not going only to that tainted node. Why is that?
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: ssdNode 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.