Scheduling Workloads¶
Volcano is a Kubernetes-based batch processing platform with high-performance general computing capabilities like task scheduling engine, heterogeneous chip management, and task running management. It provides end users with computing frameworks from multiple domains such as AI, big data, gene, and rendering. It also offers job scheduling, job management, and queue management for computing applications.
Kubernetes typically uses its default scheduler to schedule workloads. To use Volcano, specify Volcano for your workloads. For details about the Kubernetes scheduler, see Specify schedulers for pods.
Notes and Constraints¶
When a large number of workloads are scheduled, Volcano prints a large number of logs. In this case, you can use Volcano with LTS. Otherwise, the disk space of the node where Volcano resides may be used up. For details, see Collecting Container Logs.
Using Volcano¶
When using Volcano to schedule workloads, you only need to configure schedulerName in the spec field of the pod and set the parameter to volcano. The following is an example:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
labels:
app: nginx
spec:
replicas: 4
selector:
matchLabels:
app: nginx
template:
metadata:
annotations:
# Submit the job to the q1 queue.
scheduling.volcano.sh/queue-name: "q1"
volcano.sh/preemptable: "true"
labels:
app: nginx
spec:
# Specify Volcano as the scheduler.
schedulerName: volcano
containers:
- name: nginx
image: nginx
imagePullPolicy: IfNotPresent
resources:
limits:
cpu: 1
memory: 100Mi
requests:
cpu: 1
memory: 100Mi
ports:
- containerPort: 80
Additionally, Volcano supports the workload queues and preemption, which can be implemented through pod annotations. The following table lists the supported annotations.
Pod Annotations | Description |
|---|---|
scheduling.volcano.sh/queue-name: "<queue-name>" | Specifies the queue to which the workload belongs. <queue-name> indicates the queue name. |
volcano.sh/preemptable: "true" | Indicates whether a job can be preempted. If this function is enabled, the job can be preempted. Options:
|
You can obtain pod details to check whether the pod is scheduled by Volcano and the allocated queue.
kubectl describe pod <pod_name>
Command output:
Spec:
Min Member: 1
Min Resources:
Cpu: 100m
Memory: 100Mi
Queue: q1
Status:
Conditions:
Last Transition Time: 2023-05-30T01:54:43Z
Reason: tasks in gang are ready to be scheduled
Status: True
Transition ID: 70be1d7d-3532-41e0-8324-c7644026b38f
Type: Scheduled
Phase: Running
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 0s (x3 over 2s) volcano pod group is ready