To avoid contention and starvation, compute, storage, and network isolation as well as QoS policies should be applied consistently to the workloads.
The CSP admin can allocate and reserves resources for tenants by using Tenant vDCs. Every Tenant vDC is associated with a resource pool across the Resource Pods. The resource settings of the resource pool are managed from VMware Integrated OpenStack. This ensures that every Tenant vDC allocates the resources to which it is entitled, without exceeding the infrastructure resource limits, such as CPU clock cycles, total memory, network bandwidth, and storage.
QoS policies can be applied to the VMs so that they receive a fair share of resources across the infrastructure pool. Each VM configuration is taken from a template that is called a Flavor. QoS can be configured by using Flavor metadata to allocate CPU (MHz), memory (MB), storage (IOPS), and virtual interfaces (Mbps).
QoS can be shaped by setting boundary parameters that control the elasticity and priority of the resources that are assigned to the VNF component executing within the VM.
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Reservation that is the minimum guarantee. Reservations ensure a minimum guarantee to each VM when it is launched.
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Limit that is the upper boundary. Should be used with caution in a production environment, because it restricts the VM from bursting utilization beyond the configured boundaries.
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Shares that are the distribution of resources under contention. Shares can be used to prioritize certain workloads over others in case of contention. In case resources are over-provisioned across VMs and there is resource contention, the VM with the higher shares will get the proportional resource assignment.
For control plane workload functions, a higher order elasticity can be acceptable and memory can be reserved based on the workload requirement. For data plane intensive workloads, both CPU and memory should be fully reserved. Storage IO and network throughput reservations need to be determined based on the VNF needs.
