Suppose there is a k8s cluster which is made up of nodes of different hardware specs.
Then 2 pods are allocated to 2 different nodes.
Suppose the container in the pod had specified 1000m cpu.
Could the two containers running on those 2 different nodes show different levels of performance?
To ask more directly: in a heterogeneous k8s cluster, could containers perform differently(iops, cpu, mem, etc) due to which node it happens to be allocated to?
Yes. If two Pods both specify e.g. 1000m CPU and they run on different nodes, they both get an equivalent of 1 CPU core on their node. If one node has a faster CPU than the other node, then the Pod on this node correspondingly runs faster.
The same applies for other hardware characteristics of the nodes, e.g. the availability of a GPU, the speed of the memory and cache, etc.
If you want a more deterministic behaviour, you can categorise your nodes with labels or assign taints to them. Then, on the Pod side, you can influence what node a Pod gets scheduled to with tolerations, node selectors, node affinities, or even a custom scheduler.
