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Considerations for Use

Managed Port Constraints

The following ports are used for SKE management and cannot be used for service use. In addition, if blocked by OS firewall, etc., node functions or some functions may not work normally.

Port	Description
UDP 4789	calico-vxlan
TCP 5473	calico-typha
TCP 10250	kubelet
TCP 19100	node-exporter
TCP 19400	dcgm-exporter

Table. Managed Port List

kube-reserved resource constraints

kube-reserved is a feature that reserves resources for system daemons that do not run as pods on the node.

There are system daemons that do not run as pods, such as kubelet, container runtime, etc.

Reference

For more information on kube-reserved, please refer to the following document.

https://kubernetes.io/docs/tasks/administer-cluster/reserve-compute-resources/#kube-reserved

Kubernetes Engine reserves CPU and memory based on the following criteria.

CPU specification	Memory specification
First core’s 6% Next core’s 1% (up to 2 cores) Next 2 cores’ 0.5% (up to 4 cores) Cores exceeding 4 cores’ 0.25%	First 4 GB memory’s 25% Next 4 GB memory’s 20% (up to 8 GB) Next 8 GB memory’s 10% (up to 16 GB) Next 112 GB memory’s 6% (up to 128 GB) Memory exceeding 128 GB’s 2%

CPU specification

Memory specification

First core’s 6%

Next core’s 1% (up to 2 cores)

Next 2 cores’ 0.5% (up to 4 cores)

Cores exceeding 4 cores’ 0.25%

First 4 GB memory’s 25%

Next 4 GB memory’s 20% (up to 8 GB)

Next 8 GB memory’s 10% (up to 16 GB)

Next 112 GB memory’s 6% (up to 128 GB)

Memory exceeding 128 GB’s 2%

Table. Resource reservation items based on CPU and memory

Example: For a Virtual Server with 16-core vCPU and 32G Memory, kube-reserved is calculated as follows.
- CPU: (1 core × 0.06) + (1 core × 0.01) + (2 cores × 0.005) + (12 cores × 0.0025) = 0.11 core
- Memory: (4 GB × 0.25) + (4 GB × 0.2) + (8 GB × 0.1) + (16 GB × 0.06) = 3.56 GB
Example: The resources reserved according to CPU size are as follows.

CPU specification	Resource specification1	Resource specification2	Resource specification3	Resource specification4
kube-reserved CPU	70 m	80 m	90 m	110 m

Table. Example of resources reserved according to CPU size

Example: The resources reserved according to the memory size are as follows.

Memory Specification	Resource Specification1	Resource Specification2	Resource Specification3	Resource Specification4	Resource Specification4	Resource Specification4	Resource Specification4
kube-reserved memory	1 GB	1.8 GB	2.6 GB	3.56 GB	5.48 GB	9.32 GB	11.88 GB

Table. Example of resources reserved according to memory size

type LoadBalancer Service Usage