Exam Professional Cloud Network Engineer topic 1 question 116 discussion

/22 has only 1022 usable IP addresses, looks like B is the correct answer.

Vote for D 10 nodes = /28 can max 12 nodes 8 Pods per node = 80 Pods = /24 max 110 Pods 1024 services = /22 max 1024 services source: https://cloud.google.com/kubernetes-engine/docs/concepts/alias-ips

The correct answer should be D: When we have 10 nodes, we need 14 IP addresses, the first 2 and the last 2 IP addresses will be reserved, so /28 which gives 12 IP addresses. https://cloud.google.com/kubernetes-engine/docs/concepts/alias-ips#cluster_sizing_primary_range Then we should choose /24 since the smallest possible subnet range is /24 when the secondary range assignment method is user-managed: https://cloud.google.com/kubernetes-engine/docs/concepts/alias-ips#cluster_sizing_secondary_range_pods Finally, Since we can use the whole range of secondary IP addresses, /22 will be enough as it provides 1024 IP addresses for our services. https://cloud.google.com/kubernetes-engine/docs/concepts/alias-ips#cluster_sizing_secondary_range_svcs

I would tend to agree with Answer D. However it say 'Pads' versus 'Pods'. Is this a typo on the exam? If it is NOT a typo, then Answer D is wrong.

This is a tricky question. Keep in mind that Nodes use Primary IP ranges whereas Pods and Services use Secondary ranges. For secondary, as you can use all of the IP addresses unlike the Primary where 4 x IPs are reserved. E.g. Max hosts in /24 for Node is 252 vs. 256 for pods and services. If we gather the above logic: 1) 10 nodes = /28 2) 80 pods = /24 (Reason is /24 is the smallest possible Pod) 3) 1024 services = /22 (Can use all of 1024 IPs) https://cloud.google.com/kubernetes-engine/docs/concepts/alias-ips#cluster_sizing_secondary_range_pods

10 nodes = /28 (14 maximum usable IP address) 8 Pods per node = 80 Pods. But Number of IP addresses=16*10=160 = /24 (254 maximum usable IP address). Please refer: https://cloud.google.com/kubernetes-engine/docs/how-to/flexible-pod-cidr 1024 services = /21 (2046 maximum usable IP address) (/22 is not applicable as 1022 maximum usable IP address). https://www.subnet-calculator.com/cidr.php But none of the above options are fully correct. So, I will go for D

A , as /22 is 2^10-2 = 2046 services

21 is musi be so B

B is correct. Remember 1024 is the total IP in the mask /22. But the free IP to use is 1022. because of 2 more IPs, the correct is /21.

Option B specifies a /21 secondary IP range for Services, which is larger than necessary for the number of services stated in the question. Option C specifies a /28 secondary IP range for Pods, which is smaller than the minimum IP range required for Pods specified by GKE. Option D specifies a /24 secondary IP range for Pods, which violates the maximum number of Pods per node stated in the question.

vote for B, below the explanation: max node is 10 = /28 max pod is 80 = /25 max service 1024 = /21, can't use /22 because only 1022 usable ip.

Actually it must be D, as the minimum POD IP-Range is /24. This eliminates all other possibilities, right? Source: https://cloud.google.com/kubernetes-engine/docs/concepts/alias-ips?hl=de#cluster_sizing_secondary_range_pods

Configure a /28 primary IP address range for the node IP addresses. This will allow up to 16 nodes in your cluster (14 usable plus 2 reserved). For example: 10.0.0.0/28 Configure a /25 secondary IP range for the Pods. This will allow up to 128 Pods per node (126 usable plus 2 reserved). For example: 10.0.1.0/25 Configure a /22 secondary IP range for the Services. This will allow up to 1024 Services in your cluster (1022 usable plus 2 reserved). For example: 10.0.4.0/22 Therefore, the correct answer is A.

A. Configure a /28 primary IP address range for the node IP addresses. This gives you 16 possible IP addresses, which is enough for your nodes. Configure a /25 secondary IP range for the Pods. This gives you 128 possible IP addresses, which is enough for your Pods. Configure a /22 secondary IP range for the Services. This gives you 1024 possible IP addresses, which is enough for your services.

8 pod per node = 16 ips per node * 10 nodes = 160 ips > /24

Ooh. Dat question, really make me confused. For this question not working " math and typical subnet". For example with typical math /28 mask provide 14 ip. But for primary configuration for node, only 12... After researching a lot of documents. I can write some notes: "Similarly, if you set the default maximum Pods to 8 and the cluster's secondary IP address range for Pods to /21, Kubernetes assigns a /28 CIDR range to nodes. This allows a maximum of 2(28-21) = 27 = 128 nodes on the cluster." source: https://cloud.google.com/kubernetes-engine/docs/how-to/flexible-pod-cidr#configuring_maximum_pods_per_node for secondary "There are no reserved IP addresses in the secondary IP ranges." source: https://cloud.google.com/vpc/docs/subnets#reserved_ip_addresses_in_every_subnet then decide for yourself which option is correct

All the correct Maths responds to B