Resource Flavors

Overview

The bursting add-on can select appropriate pod flavors based on the CPU and memory of the workloads to improve resource utilization. This section describes how appropriate pod flavors are selected.

Constraints

At least one container in each pod to be scheduled to CCI must have the CPU limit or request.

How Pod Flavors Are Calculated

The pod flavors are calculated based on the following rules:

Requests and limits of resource X are set to the same value for all app containers and init containers. If a limit is configured, the limit will be applied. If no limit is configured, the request will be applied. Example:

If Pod P = {init_container_A, init_container_B, C, D, E}, the limit of pod P for resource X is pod_P_resource_X_Limit, and the limit of container C for resource X is C_X,

then pod_P_resource_X_Limit = max(sum(C_x, D_x, E_x), max(init_container_A, init_container_B)).

How Resource Quotas Are Rounded Up

You need to enter a set of valid CPU values based on the following formula:

C = {{c | c ∈ [0.25, 32]}, 48, 64}

Enter the number of CPU cores and the memory size (GiB).

• CPU = ceil(CPU / 0.25) * 0.25 , MEM = ceil(MEM)
• IF MEM / CPU > 8
  • CPU = MEM/8
  • CPU = ceil(CPU/0.25) x 0.25
  • If CPU ∉ C, an error will be reported.
• IF MEM/CPU < 2
  • MEM = 2 x CPU
  • MEM = ceil(MEM)
• The CPU and memory increments caused by the adjustment are added to the first non-BestEffort app container.
• You can view the flavors rounded up using the annotation of the pod in CCE.
• virtual-kubelet.cci.io/burst-pod-cpu: 500mvirtual-kubelet.cci.io/burst-pod-memory: 1Gi
• A pod to be scheduled to CCI must meet the following conditions:
  • CPU∈{{c | c ∈ [0.25, 32]}, 48, 64}; an integer multiple of 0.25
  • MEM/CPU ∈ [2, 8]
  • MEM∈{{m | m ∈ [1, 256]}, 384, 512}; an integer

Cases of Rounding Up Resource Flavors