add nodegroup plugin

docs/design/node-group.md

@@ -39,7 +39,7 @@ case2: recommend queue can use private cloud nodes or public cloud nodes, but tt
 
 affinity configure:
 1. affinity.nodeGroupAffinity.requiredDuringSchedulingIgnoredDuringExecution, hard constraints, such as `nlp = nodegroup1,nodegroup2`, it means that task in queue=nlp can ony run on the nodes in nodegroup1 or nodegroup2.
-2. affinity.nodeGroupAffinity.preferredDuringSchedulingIgnoredDuringExecution, soft constraints, such as `nlp = nodegroup1`, it means that task in queue=nlp runs on nodegroup1 first, but if the resources of nodegroup1 is insufficient, it can also run on other nodegroups.
+2. affinity.nodeGroupAffinity.preferredDuringSchedulingIgnoredDuringExecution, soft constraints, such as `nlp = nodegroup1`, it means that task in queue=nlp runs on nodegroup1 first, but if the resources of nodegroup1 is insufficient, it can also run on other nodegroups. Combine rule1 and rule2, task in queue=nlp runs on nodegroup1 first,  but if the resources of nodegroup1 is insufficient, it can also run on nodegroup2.
 3. affinity.nodeGroupAntiAffinity.requiredDuringSchedulingIgnoredDuringExecution, hard constraints, such as `nlp = nodegroup1`, it means that task in queue=nlp can run on any nodegroups but nodegroup1.
 4. affinity.nodeGroupAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution, soft constraints, such as `nlp = nodegroup1`, it means that task in queue=nlp runs on any other nodegroups, but if the resources of other nodegroup is insufficient, it can also run on nodegroup1.
 
@@ -66,3 +66,11 @@ risk: The resources of the queue can not be too different from the resources of
 ## Implement
 
 Hard constraints are implemented by using PredicateFn, and soft constraints are implemented by using NodeOrderFn.
+
+predict flow chart:
+
+![](images/nodegroup_plugin-predict-1.png)
+
+score flow chart:
+
+![](images/nodegroup_plugin-score-1.png)

docs/user-guide/how_to_use_nodegroup_plugin.md

@@ -0,0 +1,225 @@
+# Nodegroup Plugin User Guide
+
+## Introduction
+
+**Nodegroup plugin** is designed to isolate resources by assigning labels to nodes and set node label affinty on Queue.
+
+## Usage
+
+### assign label to node
+Assign label to node, label key is `volcano.sh/nodegroup-name`.
+```shell script
+kubectl label nodes <nodename> volcano.sh/nodegroup-name=<groupname>
+```
+
+### configure queue
+Create queue and bind nodegroup to it.
+
+   ```yaml
+   apiVersion: scheduling.volcano.sh/v1beta1
+   kind: Queue
+   metadata:
+     name: default
+     spec:
+       reclaimable: true
+       weight: 1
+       affinity:            # added field
+         nodeGroupAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - <groupname>
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - <groupname>
+         nodeGroupAntiAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - <groupname>
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - <groupname>
+   ```
+### submit a vcjob
+
+submit vcjob job-1 to default queue.
+
+```shell script
+$ cat <<EOF | kubectl apply -f -
+apiVersion: batch.volcano.sh/v1alpha1
+kind: Job
+metadata:
+  name: job-1
+spec:
+  minAvailable: 1
+  schedulerName: volcano
+  queue: default
+  policies:
+    - event: PodEvicted
+      action: RestartJob
+  tasks:
+    - replicas: 1
+      name: nginx
+      policies:
+      - event: TaskCompleted
+        action: CompleteJob
+      template:
+        spec:
+          containers:
+            - command:
+              - sleep
+              - 10m
+              image: nginx:latest
+              name: nginx
+              resources:
+                requests:
+                  cpu: 1
+                limits:
+                  cpu: 1
+          restartPolicy: Never
+EOF
+```
+
+### validate queue affinity and antiAffinity rules is effected
+
+Query pod information and verify whether the pod has been scheduled on the correct node. The pod should be scheduled on nodes with
+label `nodeGroupAffinity.requiredDuringSchedulingIgnoredDuringExecution` or `nodeGroupAffinity.preferredDuringSchedulingIgnoredDuringExecution`. If not, the pod should be scheduled on nodes with label of `nodeGroupAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution`. Specifically, the pod must not be scheduled on nodes with the label `nodeGroupAntiAffinity.requiredDuringSchedulingIgnoredDuringExecution`.
+
+```shell script
+kubectl get po job-1-nginx-0 -o wide 
+```
+
+## How the Nodegroup Plugin Works
+
+The nodegroup design document provides the most detailed information about the node group. There are some tips to help avoid certain issues.These tips are based on a four-nodes cluster and vcjob called job-1:
+
+| Node | Label |
+| ------ | ------ |
+| node1 | groupname1 |
+| node2 | groupname2 |
+| node3 | groupname3 |
+| node4 | groupname4 |
+
+```yaml
+apiVersion: batch.volcano.sh/v1alpha1
+kind: Job
+metadata:
+  name: job-1
+spec:
+  minAvailable: 1
+  schedulerName: volcano
+  queue: default
+  policies:
+    - event: PodEvicted
+      action: RestartJob
+  tasks:
+    - replicas: 1
+      name: nginx
+      policies:
+      - event: TaskCompleted
+        action: CompleteJob
+      template:
+        spec:
+          containers:
+            - command:
+              - sleep
+              - 10m
+              image: nginx:latest
+              name: nginx
+              resources:
+                requests:
+                  cpu: 1
+                limits:
+                  cpu: 1
+          restartPolicy: Never
+```
+
+1. Soft constraints are a subset of hard constraints, including both affinity and anti-affinity. Consider a queue setup as follows:
+   ```yaml
+   apiVersion: scheduling.volcano.sh/v1beta1
+   kind: Queue
+   metadata:
+     name: default
+     spec:
+       reclaimable: true
+       weight: 1
+       affinity:            # added field
+         nodeGroupAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+           - gropuname2
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+         nodeGroupAntiAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - groupname3
+           - gropuname4
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - groupname3
+   ```
+   This implies that tasks in the "default" queue will be scheduled on "groupname1" and "groupname2", with a preference for "groupname1" to run first. Tasks are restricted from running on "groupname3" and "groupname4". However, if the resources in other node groups are insufficient, the task can run on "nodegroup3".
+
+2. If soft constraints do not form a subset of hard constraints, the queue configuration is incorrect, leading to tasks running on "groupname2":
+    ```yaml
+   apiVersion: scheduling.volcano.sh/v1beta1
+   kind: Queue
+   metadata:
+     name: default
+     spec:
+       reclaimable: true
+       weight: 1
+       affinity:            # added field
+         nodeGroupAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - gropuname2
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+         nodeGroupAntiAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - gropuname4
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - groupname3
+   ```
+
+3. If there is a conflict between nodeGroupAffinity and nodeGroupAntiAffinity, nodeGroupAntiAffinity takes higher priority.
+   ```yaml
+   apiVersion: scheduling.volcano.sh/v1beta1
+   kind: Queue
+   metadata:
+     name: default
+     spec:
+       reclaimable: true
+       weight: 1
+       affinity:            # added field
+         nodeGroupAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+           - gropuname2
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+         nodeGroupAntiAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - gropuname2
+   ```
+   This implies that tasks in the "default" queue can only run on "groupname2".
+
+4. Generally, tasks run on "groupname1" first because it is a soft constraint. However, the scoring function comprises several plugins, so the task may sometimes run on "groupname2".
+   ```yaml
+   apiVersion: scheduling.volcano.sh/v1beta1
+   kind: Queue
+   metadata:
+     name: default
+     spec:
+       reclaimable: true
+       weight: 1
+       affinity:            # added field
+         nodeGroupAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+           - gropuname2
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - groupname1
+         nodeGroupAntiAffinity:
+           requiredDuringSchedulingIgnoredDuringExecution:
+           - groupname3
+           - gropuname4
+           preferredDuringSchedulingIgnoredDuringExecution:
+           - groupname3
+   ```