Resource quota is an object in kubernetes which enables the administrator to restrict the resource usage per namespace. In simple words, resource quota defines the limit of resource. you can limit memory, compute, storage.
you can define the limit of namespace with the resourcequota.yml file.
A request is the ammount of resource that the system will guaruntee for the container and kubernetes will use this value to decide on which node to place the pod.
A limit is the maximum ammount of resources that kubernetes will allow the container to use .
Generally, A pod in kubernetes will run with no limit of cpu and memory.But one can optionally decide how much cpu and ram each container needs. Then scheduler of master node decides in which node this pod will be placed . This will be possible when the node has enough resources according to pod needs.
sample-pod.yml is an example of resource defination of a container.