How can I list the taints on Kubernetes nodes?

Question

The docs are great about explaining how to set a taint on a node, or remove one. And I can use kubectl describe node to get a verbose description of one node, inclu

Answer 1

To find taints of node can just run:

kubectl describe nodes your-node-name

Output:

Name:                   your-node-name
...
Taints:                 node-role.kubernetes.io/master:NoSchedule
CreationTimestamp:      Wed, 19 Jul 2017 06:00:23 +0800

Answer 2

Try this one:

    kubectl get nodes -o=custom-columns=NAME:.metadata.name,TAINTS:.spec.taints

Answer 3

You can use kubectl's go-template output options to help you here,

kubectl get nodes -o go-template='{{range .items}}{{if $x := index .metadata.annotations "scheduler.alpha.kubernetes.io/taints"}}{{with $x := index .metadata.name}}{{.}}{{printf "\n"}}{{end}}{{end}}{{end}}'

On my cluster, this prints my masters, which are tainted:

kubemaster-1.example.net
kubemaster-2.example.net
kubemaster-3.example.net

Answer 4

The CMD kubectl provides an arguments jsonpath to search and format the output after getting. You can check the doc k8s jsonpath for detail.

 kubectl get node  -o=jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.taints}{"\n"}{end}'

For further info, you can check the source code that reflect the source data with the method FindResults

Answer 5

#Check Node Taints
kubectl get nodes -o=custom-columns=NodeName:.metadata.name,TaintKey:.spec.taints[*].key,TaintValue:.spec.taints[*].value,TaintEffect:.spec.taints[*].effect

Let me try and explain what this first one means and then rest should fall in place:

NodeName:.metadata.name

ColumnName: JSONPATH to the attribute you are looking for.

ColumnName can be anything you want it to be.

Something like NodeName:items[*].metadata.name is equivalent to running $kubectl get nodes -o=jsonpath='{.items[*].metadata.name}' but with custom-columns flag you get values in rows and columns format.

Note: You don't need to start with .items[*]. It already parses that with custom-column flag

so now all the columns explained:

NodeName:.metadata.name - Get Node Names and put it under NodeName Column

TaintKey:.spec.taints[*].key - return all the keys for taints by looking under taints map and put it under TaintKey custom-column

TaintValue:.spec.taints[*].value - same as key but you are returning the value from the taints map.

TaintEffect:.spec.taints[*].effect - same as key but you are returning the effect from the taints map.

You set it under and alias like

alias get-nodetaints="kubectl get nodes -o=custom-columns=NodeName:.metadata.name,TaintKey:.spec.taints[*].key,TaintValue:.spec.taints[*].value,TaintEffect:.spec.taints[*].effect"

and you have your own nice command to get all taints and your output should look something like below

sample output for the command

Answer 6

In Kubernetes 1.6.x the node taints have moved into the spec. Therefore the above answer by jaxxstorm will not work. Instead, you can use the following template.

{{printf "%-50s %-12s\n" "Node" "Taint"}}
{{- range .items}}
    {{- if $taint := (index .spec "taints") }}
        {{- .metadata.name }}{{ "\t" }}
        {{- range $taint }}
            {{- .key }}={{ .value }}:{{ .effect }}{{ "\t" }}
        {{- end }}
        {{- "\n" }}
    {{- end}}
{{- end}}

I have that saved into a file and then reference it like so:

kubectl get nodes -o go-template-file="./nodes-taints.tmpl"

You'll get output like so:

Node                                            Taint
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=etcd:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=jenkins:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=etcd:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=containerlinux-canary-channel-workers:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=jenkins:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=etcd:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=etcd:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=etcd:NoSchedule
ip-xxx-xxx-xxx-xxx.us-west-2.compute.internal   dedicate=jenkins:NoSchedule

I'm not a huge go template user so I'm sure there are some things I could have done better but it is what it is.

---

Same as above but all in one line:

kubectl get nodes -o go-template='{{printf "%-50s %-12s\n" "Node" "Taint"}}{{- range .items}}{{- if $taint := (index .spec "taints") }}{{- .metadata.name }}{{ "\t" }}{{- range $taint }}{{- .key }}={{ .value }}:{{ .effect }}{{ "\t" }}{{- end }}{{- "\n" }}{{- end}}{{- end}}'