Configuring Scheduling and Differentiation

Scheduling Policies

Currently, there are two scheduling policies: cluster weights and automatic balancing.

Configuring a Scheduling Policy on the Console

1. Log in to the UCS console.
2. When creating a workload, click Next: Scheduling and Differentiation.
3. Add a scheduling policy.

   Table 1 Scheduling policies

   Policy	Description
   Cluster weights	You need to select clusters and configure their weights. Pods are allocated to clusters based on the cluster weights.
   Auto balancing	The system automatically selects clusters to allocate pods based on the number of remaining pods. No extra configuration is required.

Calculation Method Based on Cluster Weights

Calculation Method

After you set the weight of each cluster, the number of pods allocated to each cluster is calculated as follows:

1. Formula for calculating the number of pods allocated to each cluster by cluster weight (The calculation result is rounded down.)

   Number of pods allocated to each cluster = (Total number of pods × Weight of a cluster)/Total weight of clusters

2. Formula for calculating the number of remaining pods

   Number of remaining pods = Total number of pods - Total number of pods allocated to each cluster

3. If there are any pods remaining, they will continue to be allocated by cluster weight in ascending order (one pod allocated at a time). If any clusters have the same weight, a cluster will be selected at random.

Example

There are seven pods that are assigned to three clusters named member1, member2, and member3. The clusters have weights of 2, 1, and 1, respectively.

1. The number of pods allocated to each cluster is calculated as follows:

   Number of pods allocated to member1 = 7 × 2/4 (rounded down to 3)

   Number of pods allocated to member2 = 7 × 1/4 (rounded down to 1)

   Number of pods allocated to member3 = 7 × 1/4 (rounded down to 1)

   In this initial allocation, three pods are allocated to member1, one pod to member2, and one pod to member3.

2. The number of remaining pods is calculated as follows:

   Number of remaining pods = 7 - 3 - 1 - 1 = 2

3. The remaining pods are allocated by cluster weight in ascending order.

   One pod is first allocated to member1 and the remaining pod to member2 or member3 at random.

Tolerance Policies

A tolerance policy allows the scheduler to schedule pods to clusters with corresponding taints. This policy must be used together with cluster taints.