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It is very likely that hardware devices will have unique addresses, although some virtual machines may have identical values. Kubernetes uses these values to uniquely identify the nodes in the cluster. If these values are not unique to each node, the installation process may fail.
Check Network Adapters
If you have more than one network adapter, and your Kubernetes components are not reachable on the default route, we recommend you add IP route(s) so Kubernetes cluster addresses go via the appropriate adapter.
Check Required Ports
Master Cluster Master Node(s)
Protocol | Direction | Port Range | Purpose |
TCP | Inbound | 6443* | Kubernetes API server |
TCP | Inbound | 2379-2380 | etcd server client API |
TCP | Inbound | 10250 | kubelet API |
TCP | Inbound | 10251 | kube-scheduler |
TCP | Inbound | 10252 | kube-controller-manager |
TCP | Inbound | 10255 | Read-only kubelet API |
Worker Node(s)& User Cluster Worker Nodes
Protocol | Direction | Port Range | Purpose |
TCP | Inbound | 10250 | kubelet API |
TCP | Inbound | 10255 | Read-only kubelet API |
TCP | Inbound | 30000-32767 | NodePort Services** |
** Default port range for NodePort Services.
Any port numbers marked with * are overridable, so you will need to ensure any custom ports you provide are also open.