diff --git a/pkg/cluster/pool.go b/pkg/cluster/pool.go
index a297649..710b0a3 100644
--- a/pkg/cluster/pool.go
+++ b/pkg/cluster/pool.go
@@ -84,14 +84,19 @@ func (pool *NodePool) GetNodeByID(id uint) Node {
 
 func (pool *NodePool) nodeStatusChange(isActive bool, id uint) {
 	util.Log().Debug("从机节点 [ID=%d] 状态变更 [Active=%t]", id, isActive)
+	var node Node
 	pool.lock.Lock()
-	if isActive {
-		node := pool.inactive[id]
+	if n, ok := pool.inactive[id]; ok {
+		node = n
 		delete(pool.inactive, id)
-		pool.active[id] = node
 	} else {
-		node := pool.active[id]
+		node = pool.active[id]
 		delete(pool.active, id)
+	}
+
+	if isActive {
+		pool.active[id] = node
+	} else {
 		pool.inactive[id] = node
 	}
 	pool.lock.Unlock()
diff --git a/pkg/cluster/pool_test.go b/pkg/cluster/pool_test.go
index 5af3fc4..dde3455 100644
--- a/pkg/cluster/pool_test.go
+++ b/pkg/cluster/pool_test.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"github.com/DATA-DOG/go-sqlmock"
 	model "github.com/cloudreve/Cloudreve/v3/models"
+	"github.com/cloudreve/Cloudreve/v3/pkg/balancer"
 	"github.com/jinzhu/gorm"
 	"github.com/stretchr/testify/assert"
 	"testing"
@@ -60,5 +61,101 @@ func TestNodePool_GetNodeByID(t *testing.T) {
 }
 
 func TestNodePool_NodeStatusChange(t *testing.T) {
+	a := assert.New(t)
+	p := &NodePool{}
+	n := &MasterNode{Model: &model.Node{}}
+	p.Init()
+	p.inactive[1] = n
+
+	p.nodeStatusChange(true, 1)
+	a.Len(p.inactive, 0)
+	a.Equal(n, p.active[1])
+
+	p.nodeStatusChange(false, 1)
+	a.Len(p.active, 0)
+	a.Equal(n, p.inactive[1])
+
+	p.nodeStatusChange(false, 1)
+	a.Len(p.active, 0)
+	a.Equal(n, p.inactive[1])
+}
+
+func TestNodePool_Add(t *testing.T) {
+	a := assert.New(t)
+	p := &NodePool{}
+	p.Init()
 
+	// new node
+	{
+		p.Add(&model.Node{})
+		a.Len(p.active, 1)
+	}
+
+	// old node
+	{
+		p.inactive[0] = p.active[0]
+		delete(p.active, 0)
+		p.Add(&model.Node{})
+		a.Len(p.active, 0)
+		a.Len(p.inactive, 1)
+	}
+}
+
+func TestNodePool_Delete(t *testing.T) {
+	a := assert.New(t)
+	p := &NodePool{}
+	p.Init()
+
+	// active
+	{
+		mockNode := &nodeMock{}
+		mockNode.On("Kill")
+		p.active[0] = mockNode
+		p.Delete(0)
+		a.Len(p.active, 0)
+		a.Len(p.inactive, 0)
+		mockNode.AssertExpectations(t)
+	}
+
+	p.Init()
+
+	// inactive
+	{
+		mockNode := &nodeMock{}
+		mockNode.On("Kill")
+		p.inactive[0] = mockNode
+		p.Delete(0)
+		a.Len(p.active, 0)
+		a.Len(p.inactive, 0)
+		mockNode.AssertExpectations(t)
+	}
+}
+
+func TestNodePool_BalanceNodeByFeature(t *testing.T) {
+	a := assert.New(t)
+	p := &NodePool{}
+	p.Init()
+
+	// success
+	{
+		p.featureMap["test"] = []Node{&MasterNode{}}
+		err, res := p.BalanceNodeByFeature("test", balancer.NewBalancer("round-robin"))
+		a.NoError(err)
+		a.Equal(p.featureMap["test"][0], res)
+	}
+
+	// NoNodes
+	{
+		p.featureMap["test"] = []Node{}
+		err, res := p.BalanceNodeByFeature("test", balancer.NewBalancer("round-robin"))
+		a.Error(err)
+		a.Nil(res)
+	}
+
+	// No match feature
+	{
+		err, res := p.BalanceNodeByFeature("test2", balancer.NewBalancer("round-robin"))
+		a.Error(err)
+		a.Nil(res)
+	}
 }
diff --git a/pkg/cluster/slave_test.go b/pkg/cluster/slave_test.go
new file mode 100644
index 0000000..0b70caa
--- /dev/null
+++ b/pkg/cluster/slave_test.go
@@ -0,0 +1,443 @@
+package cluster
+
+import (
+	model "github.com/cloudreve/Cloudreve/v3/models"
+	"github.com/cloudreve/Cloudreve/v3/pkg/cache"
+	"github.com/cloudreve/Cloudreve/v3/pkg/request"
+	"github.com/cloudreve/Cloudreve/v3/pkg/serializer"
+	"github.com/stretchr/testify/assert"
+	testMock "github.com/stretchr/testify/mock"
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestSlaveNode_InitAndKill(t *testing.T) {
+	a := assert.New(t)
+	n := &SlaveNode{
+		callback: func(b bool, u uint) {
+
+		},
+	}
+
+	a.NotPanics(func() {
+		n.Init(&model.Node{})
+		time.Sleep(time.Millisecond * 500)
+		n.Init(&model.Node{})
+		n.Kill()
+	})
+}
+
+func TestSlaveNode_DummyMethods(t *testing.T) {
+	a := assert.New(t)
+	m := &SlaveNode{
+		Model: &model.Node{},
+	}
+
+	m.Model.ID = 5
+	a.Equal(m.Model.ID, m.ID())
+	a.Equal(m.Model.ID, m.DBModel().ID)
+
+	a.False(m.IsActive())
+	a.False(m.IsMater())
+
+	m.SubscribeStatusChange(func(isActive bool, id uint) {})
+}
+
+func TestSlaveNode_IsFeatureEnabled(t *testing.T) {
+	a := assert.New(t)
+	m := &SlaveNode{
+		Model: &model.Node{},
+	}
+
+	a.False(m.IsFeatureEnabled("aria2"))
+	a.False(m.IsFeatureEnabled("random"))
+	m.Model.Aria2Enabled = true
+	a.True(m.IsFeatureEnabled("aria2"))
+}
+
+func TestSlaveNode_Ping(t *testing.T) {
+	a := assert.New(t)
+	m := &SlaveNode{
+		Model: &model.Node{},
+	}
+
+	// master return error code
+	{
+		mockRequest := &requestMock{}
+		mockRequest.On("Request", "POST", "heartbeat", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"code\":1}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.Ping(&serializer.NodePingReq{})
+		a.Error(err)
+		a.Nil(res)
+		a.Equal(1, err.(serializer.AppError).Code)
+	}
+
+	// return unexpected json
+	{
+		mockRequest := &requestMock{}
+		mockRequest.On("Request", "POST", "heartbeat", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"233\"}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.Ping(&serializer.NodePingReq{})
+		a.Error(err)
+		a.Nil(res)
+	}
+
+	// return success
+	{
+		mockRequest := &requestMock{}
+		mockRequest.On("Request", "POST", "heartbeat", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"{}\"}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.Ping(&serializer.NodePingReq{})
+		a.NoError(err)
+		a.NotNil(res)
+	}
+}
+
+func TestSlaveNode_GetAria2Instance(t *testing.T) {
+	a := assert.New(t)
+	m := &SlaveNode{
+		Model: &model.Node{},
+	}
+
+	a.NotNil(m.GetAria2Instance())
+	m.Model.Aria2Enabled = true
+	a.NotNil(m.GetAria2Instance())
+	a.NotNil(m.GetAria2Instance())
+}
+
+func TestSlaveNode_StartPingLoop(t *testing.T) {
+	callbackCount := 0
+	finishedChan := make(chan struct{})
+	mockRequest := requestMock{}
+	mockRequest.On("Request", "POST", "heartbeat", testMock.Anything, testMock.Anything).Return(&request.Response{
+		Response: &http.Response{
+			StatusCode: 404,
+		},
+	})
+	m := &SlaveNode{
+		Active: true,
+		Model:  &model.Node{},
+		callback: func(b bool, u uint) {
+			callbackCount++
+			if callbackCount == 2 {
+				close(finishedChan)
+			}
+			if callbackCount == 1 {
+				mockRequest.AssertExpectations(t)
+				mockRequest = requestMock{}
+				mockRequest.On("Request", "POST", "heartbeat", testMock.Anything, testMock.Anything).Return(&request.Response{
+					Response: &http.Response{
+						StatusCode: 200,
+						Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"{}\"}")),
+					},
+				})
+			}
+		},
+	}
+	cache.Set("setting_slave_ping_interval", "0", 0)
+	cache.Set("setting_slave_recover_interval", "0", 0)
+	cache.Set("setting_slave_node_retry", "1", 0)
+
+	m.caller.Client = &mockRequest
+	go func() {
+		select {
+		case <-finishedChan:
+			m.Kill()
+		}
+	}()
+	m.StartPingLoop()
+	mockRequest.AssertExpectations(t)
+}
+
+func TestSlaveNode_AuthInstance(t *testing.T) {
+	a := assert.New(t)
+	m := &SlaveNode{
+		Model: &model.Node{},
+	}
+
+	a.NotNil(m.MasterAuthInstance())
+	a.NotNil(m.SlaveAuthInstance())
+}
+
+func TestSlaveNode_ChangeStatus(t *testing.T) {
+	a := assert.New(t)
+	isActive := false
+	m := &SlaveNode{
+		Model: &model.Node{},
+		callback: func(b bool, u uint) {
+			isActive = b
+		},
+	}
+
+	a.NotPanics(func() {
+		m.changeStatus(false)
+	})
+	m.changeStatus(true)
+	a.True(isActive)
+}
+
+func getTestRPCNodeSlave() *SlaveNode {
+	m := &SlaveNode{
+		Model: &model.Node{},
+	}
+	m.caller.parent = m
+	return m
+}
+
+func TestSlaveCaller_CreateTask(t *testing.T) {
+	a := assert.New(t)
+	m := getTestRPCNodeSlave()
+
+	// master return 404
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/task", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 404,
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.caller.CreateTask(&model.Download{}, nil)
+		a.Empty(res)
+		a.Error(err)
+	}
+
+	// master return error
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/task", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"code\":1}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.caller.CreateTask(&model.Download{}, nil)
+		a.Empty(res)
+		a.Error(err)
+	}
+
+	// master return success
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/task", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"res\"}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.caller.CreateTask(&model.Download{}, nil)
+		a.Equal("res", res)
+		a.NoError(err)
+	}
+}
+
+func TestSlaveCaller_Status(t *testing.T) {
+	a := assert.New(t)
+	m := getTestRPCNodeSlave()
+
+	// master return 404
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/status", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 404,
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.caller.Status(&model.Download{})
+		a.Empty(res.Status)
+		a.Error(err)
+	}
+
+	// master return error
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/status", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"code\":1}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.caller.Status(&model.Download{})
+		a.Empty(res.Status)
+		a.Error(err)
+	}
+
+	// master return success
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/status", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"re456456s\"}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		res, err := m.caller.Status(&model.Download{})
+		a.Empty(res.Status)
+		a.NoError(err)
+	}
+}
+
+func TestSlaveCaller_Cancel(t *testing.T) {
+	a := assert.New(t)
+	m := getTestRPCNodeSlave()
+
+	// master return 404
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/cancel", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 404,
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.Cancel(&model.Download{})
+		a.Error(err)
+	}
+
+	// master return error
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/cancel", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"code\":1}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.Cancel(&model.Download{})
+		a.Error(err)
+	}
+
+	// master return success
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/cancel", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"res\"}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.Cancel(&model.Download{})
+		a.NoError(err)
+	}
+}
+
+func TestSlaveCaller_Select(t *testing.T) {
+	a := assert.New(t)
+	m := getTestRPCNodeSlave()
+	m.caller.Init()
+	m.caller.GetConfig()
+
+	// master return 404
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/select", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 404,
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.Select(&model.Download{}, nil)
+		a.Error(err)
+	}
+
+	// master return error
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/select", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"code\":1}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.Select(&model.Download{}, nil)
+		a.Error(err)
+	}
+
+	// master return success
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/select", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"res\"}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.Select(&model.Download{}, nil)
+		a.NoError(err)
+	}
+}
+
+func TestSlaveCaller_DeleteTempFile(t *testing.T) {
+	a := assert.New(t)
+	m := getTestRPCNodeSlave()
+	m.caller.Init()
+	m.caller.GetConfig()
+
+	// master return 404
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/delete", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 404,
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.DeleteTempFile(&model.Download{})
+		a.Error(err)
+	}
+
+	// master return error
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/delete", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"code\":1}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.DeleteTempFile(&model.Download{})
+		a.Error(err)
+	}
+
+	// master return success
+	{
+		mockRequest := requestMock{}
+		mockRequest.On("Request", "POST", "aria2/delete", testMock.Anything, testMock.Anything).Return(&request.Response{
+			Response: &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(strings.NewReader("{\"data\":\"res\"}")),
+			},
+		})
+		m.caller.Client = mockRequest
+		err := m.caller.DeleteTempFile(&model.Download{})
+		a.NoError(err)
+	}
+}