Proportion

Overview

The Proportion scheduling algorithm uses the concept of Queue to control the proportion of total resources allocated in the cluster. Each queue is allocated a certain proportion of cluster resources.

For example, if there are three teams sharing a pool of resources on a cluster:

• Team A can use up to 40% of the total cluster
• Team B can use up to 30%
• Team C can use up to 30%

If the amount of work delivered exceeds the team's maximum available resources, the jobs will be queued.

How It Works

The Proportion plugin manages resource allocation based on queue configurations:

• Queue Weight: Each queue has a weight that determines its share of cluster resources
• Capability: Maximum resources a queue can use
• Guarantee: Minimum resources guaranteed to a queue
• Deserved Resources: Resources a queue should receive based on its weight

Key functions implemented:

• QueueOrderFn: Orders queues for scheduling based on their resource utilization
• ReclaimableFn: Determines if resources can be reclaimed from a queue
• OverusedFn: Checks if a queue is using more than its deserved share

Scenario

The Proportion scheduling algorithm improves the flexibility and elasticity of cluster scheduling:

Multi-team Resource Sharing

The most typical scenario is when multiple development teams in a company share a cluster. This scheduling algorithm handles the requirements of shared resource allocation and isolation between different departments very well.

Multi-service Mixed Scenarios

In environments with diverse workloads:

• Computation-intensive: AI business
• Network IO-intensive: MPI and HPC business
• Storage-intensive: Big data business

The Proportion scheduling algorithm can allocate shared resources according to demand through matching.

Configuration

Queue Definition

First, create queues with appropriate resource allocations:

apiVersion: scheduling.volcano.sh/v1beta1
kind: Queue
metadata:
  name: team-a-queue
spec:
  weight: 4
  capability:
    cpu: "40"
    memory: "80Gi"
---
apiVersion: scheduling.volcano.sh/v1beta1
kind: Queue
metadata:
  name: team-b-queue
spec:
  weight: 3
  capability:
    cpu: "30"
    memory: "60Gi"
---
apiVersion: scheduling.volcano.sh/v1beta1
kind: Queue
metadata:
  name: team-c-queue
spec:
  weight: 3
  capability:
    cpu: "30"
    memory: "60Gi"

Scheduler Configuration

Enable the Proportion plugin in the scheduler:

tiers:
- plugins:
  - name: priority
  - name: gang
- plugins:
  - name: drf
  - name: predicates
  - name: proportion
  - name: nodeorder

Example

Using Queues in VolcanoJob

Submit jobs to specific queues:

apiVersion: batch.volcano.sh/v1alpha1
kind: Job
metadata:
  name: team-a-job
spec:
  schedulerName: volcano
  queue: team-a-queue
  minAvailable: 2
  tasks:
  - replicas: 2
    name: worker
    template:
      spec:
        containers:
        - name: worker
          image: busybox
          resources:
            requests:
              cpu: "2"
              memory: "4Gi"

Queue with Guarantee and Capability

Create a queue with both minimum guarantee and maximum capability:

apiVersion: scheduling.volcano.sh/v1beta1
kind: Queue
metadata:
  name: production-queue
spec:
  weight: 5
  guarantee:
    resource:
      cpu: "10"
      memory: "20Gi"
  capability:
    cpu: "50"
    memory: "100Gi"
  reclaimable: true

In this configuration:

• The queue is guaranteed at least 10 CPUs and 20Gi memory
• It can use up to 50 CPUs and 100Gi memory when resources are available
• Resources can be reclaimed from this queue when other queues need them