When I studying about Resource Quotas, I found somethings very similar, e.g:
memory
vs. requests.memory
pods
vs. count/pods
So, my question is what's the different between them?
I think you are confusing Compute Resource Quota with Object Count Quota
Compute Resource Quota
The total sum of compute resources that can be requested in a given namespace.
requests.memory
- for instance you can set in this way the total guaranteed amount of memory for Dev team in their dev namespace taking into account all Pods' containers.
Object Count Quota
The total number of generic objects that can exist in the namespace.
count/services or pods
- possible use case, limit the maximum number of pods per namespace, quoting the official documentation:
You might want to set a pods quota on a namespace to avoid the case where a user creates many small pods and exhausts the cluster’s supply of Pod IPs.