It's a customized scheduler try to resolve parallel tasks depends on …

…same volume but maybe run on different nodes.

This is a draft version, try to introduce `Scheduler framework` to handle the issue, for now we adopt `affinity assistant` but has issue to measure total resource requirements.

Details please check issue: tektoncd/pipeline#3052

I think we will enhance it soon based on further discussion, thanks.

scheduler/Dockerfile

@@ -0,0 +1,7 @@
+FROM debian:stretch-slim
+
+WORKDIR /
+
+COPY bin/kube-scheduler /usr/local/bin
+
+CMD ["kube-scheduler"]

scheduler/Makefile

@@ -0,0 +1,45 @@
+# Copyright 2020 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+COMMONENVVAR=GOOS=$(shell uname -s | tr A-Z a-z) GOARCH=$(subst x86_64,amd64,$(patsubst i%86,386,$(shell uname -m)))
+BUILDENVVAR=CGO_ENABLED=0
+# If tag not explicitly set in users default to the git sha.
+TAG ?= v0.0.1
+
+.PHONY: all
+all: build
+
+.PHONY: build
+build: autogen
+	$(COMMONENVVAR) $(BUILDENVVAR) go build -ldflags '-w' -o bin/kube-scheduler cmd/main.go
+
+.PHONY: update-vendor
+update-vendor:
+	hack/update-vendor.sh
+
+.PHONY: unit-test
+unit-test: update-vendor
+	hack/unit-test.sh
+
+.PHONY: autogen
+autogen: update-vendor
+	hack/update-generated-openapi.sh
+
+.PHONY: verify-gofmt
+verify-gofmt:
+	hack/verify-gofmt.sh
+
+.PHONY: image
+image: build
+	docker build  . -t vincentpli/scheduler-framework-sample:$(TAG)

scheduler/README.md

@@ -0,0 +1,24 @@
+# coscheduler-same-node
+The repo is for trying to implements such a scheduler:
+https://github.com/tektoncd/pipeline/issues/3052
+
+# Installation
+```
+make image
+docker push
+```
+
+# Take a try
+`kubectl create -f manifests/sample/pods.yaml`
+
+# Description
+The `scheduler` is based on [Scheduler plugin framework](https://github.com/kubernetes/enhancements/blob/master/keps/sig-scheduling/20180409-scheduling-framework.md)
+
+Use special labels of `pod` to mark the group of pods.
+```
+labels:
+     pod-group.scheduling.sigs.k8s.io/name: test
+     pod-group.scheduling.sigs.k8s.io/total: "2"
+```
+
+The `pod`s in same `pod-group` will be scheduler to same node if the node can satisfy the resource requirement of whole group.

scheduler/cmd/main.go

@@ -0,0 +1,40 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"math/rand"
+	"os"
+	"time"
+
+	"k8s.io/kubernetes/cmd/kube-scheduler/app"
+
+	"sigs.k8s.io/scheduler-plugins/pkg/coscheduler"
+)
+
+func main() {
+	rand.Seed(time.Now().UnixNano())
+	// Register custom plugins to the scheduler framework.
+	// Later they can consist of scheduler profile(s) and hence
+	// used by various kinds of workloads.
+	command := app.NewSchedulerCommand(
+		app.WithPlugin(coscheduler.CoschedulerName, coscheduler.NewCoscheduler),
+	)
+	if err := command.Execute(); err != nil {
+		os.Exit(1)
+	}
+}

scheduler/go.mod

@@ -0,0 +1,36 @@
+module sigs.k8s.io/scheduler-plugins
+
+go 1.13
+
+require (
+	k8s.io/api v0.18.0
+	k8s.io/apimachinery v0.18.0
+	k8s.io/apiserver v0.18.0
+	k8s.io/client-go v0.18.0
+	k8s.io/klog v1.0.0
+	k8s.io/kubernetes v1.18.0
+)
+
+replace (
+	k8s.io/api => k8s.io/api v0.18.0
+	k8s.io/apiextensions-apiserver => k8s.io/apiextensions-apiserver v0.18.0
+	k8s.io/apimachinery => k8s.io/apimachinery v0.18.0
+	k8s.io/apiserver => k8s.io/apiserver v0.18.0
+	k8s.io/cli-runtime => k8s.io/cli-runtime v0.18.0
+	k8s.io/client-go => k8s.io/client-go v0.18.0
+	k8s.io/cloud-provider => k8s.io/cloud-provider v0.18.0
+	k8s.io/cluster-bootstrap => k8s.io/cluster-bootstrap v0.18.0
+	k8s.io/code-generator => k8s.io/code-generator v0.18.0
+	k8s.io/component-base => k8s.io/component-base v0.18.0
+	k8s.io/cri-api => k8s.io/cri-api v0.18.0
+	k8s.io/csi-translation-lib => k8s.io/csi-translation-lib v0.18.0
+	k8s.io/kube-aggregator => k8s.io/kube-aggregator v0.18.0
+	k8s.io/kube-controller-manager => k8s.io/kube-controller-manager v0.18.0
+	k8s.io/kube-proxy => k8s.io/kube-proxy v0.18.0
+	k8s.io/kube-scheduler => k8s.io/kube-scheduler v0.18.0
+	k8s.io/kubectl => k8s.io/kubectl v0.18.0
+	k8s.io/kubelet => k8s.io/kubelet v0.18.0
+	k8s.io/legacy-cloud-providers => k8s.io/legacy-cloud-providers v0.18.0
+	k8s.io/metrics => k8s.io/metrics v0.18.0
+	k8s.io/sample-apiserver => k8s.io/sample-apiserver v0.18.0
+)