docs/scheduler/strategy/binpacking_test.go

package strategy

import (
	"fmt"
	"testing"

	"github.com/docker/swarm/cluster"
	"github.com/samalba/dockerclient"
	"github.com/stretchr/testify/assert"
)

func createNode(ID string, memory int64, cpus int64) *cluster.Node {
	node := cluster.NewNode(ID)
	node.ID = ID
	node.Memory = memory * 1024 * 1024 * 1024
	node.Cpus = cpus
	return node
}

func createConfig(memory int64, cpus int64) *dockerclient.ContainerConfig {
	return &dockerclient.ContainerConfig{Memory: memory * 1024 * 1024 * 1024, CpuShares: cpus}
}

func createContainer(ID string, config *dockerclient.ContainerConfig) *cluster.Container {
	return &cluster.Container{Container: dockerclient.Container{Id: ID}, Info: dockerclient.ContainerInfo{Config: config}}
}

func TestPlaceContainerMemory(t *testing.T) {
	s := &BinPackingPlacementStrategy{}

	nodes := []*cluster.Node{}
	for i := 0; i < 2; i++ {
		nodes = append(nodes, createNode(fmt.Sprintf("node-%d", i), 2, 1))
	}

	// add 1 container 1G
	config := createConfig(1, 0)
	node1, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node1.AddContainer(createContainer("c1", config))

	assert.Equal(t, node1.ReservedMemory(), 1024*1024*1024)

	// add another container 1G
	config = createConfig(1, 1)
	node2, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node2.AddContainer(createContainer("c2", config))

	assert.Equal(t, node2.ReservedMemory(), 2*1024*1024*1024)

	// check that both containers ended on the same node
	assert.Equal(t, node1.ID, node2.ID, "")
	assert.Equal(t, len(node1.Containers()), len(node2.Containers()), "")

}

func TestPlaceContainerCPU(t *testing.T) {
	s := &BinPackingPlacementStrategy{}

	nodes := []*cluster.Node{}
	for i := 0; i < 2; i++ {
		nodes = append(nodes, createNode(fmt.Sprintf("node-%d", i), 1, 2))
	}

	// add 1 container 1CPU
	config := createConfig(0, 1)
	node1, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node1.AddContainer(createContainer("c1", config))

	assert.Equal(t, node1.ReservedCpus(), 1)

	// add another container 1CPU
	config = createConfig(0, 1)
	node2, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node2.AddContainer(createContainer("c2", config))

	assert.Equal(t, node2.ReservedCpus(), 2)

	// check that both containers ended on the same node
	assert.Equal(t, node1.ID, node2.ID, "")
	assert.Equal(t, len(node1.Containers()), len(node2.Containers()), "")

}

func TestPlaceContainerHuge(t *testing.T) {
	s := &BinPackingPlacementStrategy{}

	nodes := []*cluster.Node{}
	for i := 0; i < 100; i++ {
		nodes = append(nodes, createNode(fmt.Sprintf("node-%d", i), 1, 1))
	}

	// add 100 container 1CPU
	for i := 0; i < 100; i++ {
		node, err := s.PlaceContainer(createConfig(0, 1), nodes)
		assert.NoError(t, err)
		node.AddContainer(createContainer(fmt.Sprintf("c%d", i), createConfig(0, 100)))
	}

	// try to add another container 1CPU
	_, err := s.PlaceContainer(createConfig(0, 1), nodes)
	assert.Error(t, err)

	// add 100 container 1G
	for i := 0; i < 100; i++ {
		node, err := s.PlaceContainer(createConfig(1, 0), nodes)
		assert.NoError(t, err)
		node.AddContainer(createContainer(fmt.Sprintf("c%d", i), createConfig(1, 0)))
	}

	// try to add another container 1G
	_, err = s.PlaceContainer(createConfig(1, 0), nodes)
	assert.Error(t, err)

}

// The demo
func TestPlaceContainerDemo(t *testing.T) {
	s := &BinPackingPlacementStrategy{}

	nodes := []*cluster.Node{}
	for i := 0; i < 3; i++ {
		nodes = append(nodes, createNode(fmt.Sprintf("node-%d", i), 2, 4))
	}

	// try to place a 10G container
	config := createConfig(10, 0)
	_, err := s.PlaceContainer(config, nodes)

	// check that it refuses because the cluster is full
	assert.Error(t, err)

	// add one container 1G
	config = createConfig(1, 0)
	node1, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node1.AddContainer(createContainer("c1", config))

	// add another container 1G
	config = createConfig(1, 0)
	node1bis, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node1bis.AddContainer(createContainer("c2", config))

	// check that both containers ended on the same node
	assert.Equal(t, node1.ID, node1bis.ID, "")
	assert.Equal(t, len(node1.Containers()), len(node1bis.Containers()), "")

	// add another container 2G
	config = createConfig(2, 0)
	node2, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node2.AddContainer(createContainer("c3", config))

	// check that it ends up on another node
	assert.NotEqual(t, node1.ID, node2.ID, "")

	// add another container 1G
	config = createConfig(1, 0)
	node3, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node3.AddContainer(createContainer("c4", config))

	// check that it ends up on another node
	assert.NotEqual(t, node1.ID, node3.ID, "")
	assert.NotEqual(t, node2.ID, node3.ID, "")

	// add another container 1G
	config = createConfig(1, 0)
	node3bis, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node3bis.AddContainer(createContainer("c5", config))

	// check that it ends up on the same node
	assert.Equal(t, node3.ID, node3bis.ID, "")

	// try to add another container
	config = createConfig(1, 0)
	_, err = s.PlaceContainer(config, nodes)

	// check that it refuses because the cluster is full
	assert.Error(t, err)

	// remove container in the middle
	node2.CleanupContainers()

	// add another container
	config = createConfig(1, 0)
	node2bis, err := s.PlaceContainer(config, nodes)
	assert.NoError(t, err)
	node2bis.AddContainer(createContainer("c6", config))

	// check it ends up on `node3`
	assert.Equal(t, node2.ID, node2bis.ID, "")
	assert.Equal(t, len(node2.Containers()), len(node2bis.Containers()), "")
}