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website/content/en/docs/reference/ports-and-protocols.md
Pushkar Joglekar 7655d8d778 Add a ports and protocols reference page
- Refactored ports and protocols info under docs/reference
- Updated the ports for kube-scheduler and kube-controller based on
  current state

Co-authored-by: Tim Bannister <tim@scalefactory.com>
2021-09-15 13:19:04 -07:00

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Ports and Protocols reference 50

When running Kubernetes in an environment with strict network boundaries, such as on-premises datacenter with physical network firewalls or Virtual Networks in Public Cloud, it is useful to be aware of the ports and protocols used by Kubernetes components

Control plane

Protocol Direction Port Range Purpose Used By
TCP Inbound 6443 Kubernetes API server All
TCP Inbound 2379-2380 etcd server client API kube-apiserver, etcd
TCP Inbound 10250 Kubelet API Self, Control plane
TCP Inbound 10259 kube-scheduler Self
TCP Inbound 10257 kube-controller-manager Self

Although etcd ports are included in control plane section, you can also host your own etcd cluster externally or on custom ports.

Worker node(s)

Protocol Direction Port Range Purpose Used By
TCP Inbound 10250 Kubelet API Self, Control plane
TCP Inbound 30000-32767 NodePort Services† All

† Default port range for NodePort Services.

All default port numbers can be overridden. When custom ports are used those ports need to be open instead of defaults mentioned here.

One common example is API server port that is sometimes switched to 443. Alternatively, the default port is kept as is and API server is put behind a load balancer that listens on 443 and routes the requests to API server on the default port.