NodePort Parameter Modification

1. API Server NodePort Range Modification

In the UK8S cluster, the APIServer related parameters are stored in the /etc/kubernetes/apiserver file on the Master node. Please perform the following operations on each Master node.

Backup this configuration file and modify the --service-node-port-range to the desired parameter in the file.

KUBE_API_ARGS=" --... \
                --... \
                --service-node-port-range=30000-32767 \
                --... \
                --..."

After the modification is completed, restart the APIServer through systemctl restart kube-apiserver.

⚠️ If the Service in the cluster has been assigned a port outside the target NodePort Range, after modification, check the cluster events through kubectl get event -A, there will be a warning event similar to the following The warning event does not affect the use of this port. If you want to avoid this warning, you need to rebuild the Service.

# kubectl get event -A
NAMESPACE      LAST SEEN   TYPE      REASON             OBJECT                         MESSAGE
uk8s-monitor   79s         Warning   PortOutOfRange     service/grafana                Port 34840 is not within the port range 30000-32767; please recreate service
uk8s-monitor   78s         Warning   PortNotAllocated   service/grafana                Port 34840 is not allocated; repairing

2. Modify the node ip_local_port_range

Check the current system open port range, as follows:

# cat /proc/sys/net/ipv4/ip_local_port_range 
12000 65535

If you need to modify it, please change the net.ipv4.ip_local_port_range field in the /etc/sysctl.conf file.

net.ipv4.ip_local_port_range = 32768 60999

After the modification is completed, execute sysctl -p to take the configuration into effect, and verify again:

# cat /proc/sys/net/ipv4/ip_local_port_range 
32768 60999