CODEWITHSUNDEEP
kubernetes
zjffdu
zjffdu

Reputation: 28870

How can I know which port is available in node if I wan to use NodePort in kubernetes

I'd like to specify port when using NodePort, but how can I know which port is available on all nodes, I don't want to port conflicts.

Upvotes: 0

Views: 124

Answers (4)

rajesh-nitc
rajesh-nitc

Reputation: 5549

Right approach is to let Kubernetes choose the nodePort automatically from the default allocated range(30000–32767). Don't include nodePort in your yaml.

Upvotes: 1

Vishnu Hari Dadhich
Vishnu Hari Dadhich

Reputation: 96

You could do netstat | grep <port> .

If you set the type field to NodePort, the Kubernetes control plane will allocate a port from a range specified by --service-node-port-range flag (default: 30000-32767). Each node will proxy that port each (the same port number on every Node) into your Service.

Upvotes: 0

polve
polve

Reputation: 3148

You could get all services, grep node port and see what comes out.

$ kubectl get services --all-namespaces -o yaml |grep "nodePort:"|sort
  nodePort: 30215
  nodePort: 30274
  nodePort: 30312
  nodePort: 30342
  nodePort: 30344
  nodePort: 30386
  nodePort: 30517
  nodePort: 30738
  nodePort: 30863
  nodePort: 31063
  nodePort: 31162
  nodePort: 31445

Or pipe to jq with json output if you want a more elaborate listing with service names and so on.

Edit: the port range for node ports is normally 30000-32767 and should be reserved for Kubernetes use to avoid conflicts.

Upvotes: 0

Abhyudit Jain
Abhyudit Jain

Reputation: 3748

You can get all the services using

kubectl get svc --all-namespaces

Then you can grep using the type.

There you can see all the assigned ports. It's basic piping and output filtering.

kubectl get svc --all-namespaces | grep ClusterIP | while read -r _ _ _ _ _ port _; do echo "$port" ; done

Upvotes: 0

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