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这篇文章主要介绍“Device Manager在什么时候创建”，在日常操作中，相信很多人在Device Manager在什么时候创建问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”Device Manager在什么时候创建”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
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Device Manager和Volume Manager、QoS Container Manager等一样，都属于kubelet管理的众多Manager之一。Device Manager在kubelet启动时的NewContainerManager中创建。
pkg/kubelet/cm/container_manager_linux.go:197
func NewContainerManager(mountUtil mount.Interface, cadvisorInterface cadvisor.Interface, nodeConfig NodeConfig, failSwapOn bool, devicePluginEnabled bool, recorder record.EventRecorder) (ContainerManager, error) {
...
glog.Infof("Creating device plugin manager: %t", devicePluginEnabled)
if devicePluginEnabled {
cm.deviceManager, err = devicemanager.NewManagerImpl()
} else {
cm.deviceManager, err = devicemanager.NewManagerStub()
}
if err != nil {
return nil, err
}
...
} 我们有必要先了解Device Manager的结构体：
// ManagerImpl is the structure in charge of managing Device Plugins.
type ManagerImpl struct {
socketname string
socketdir string
endpoints map[string]endpoint // Key is ResourceName
mutex sync.Mutex
server *grpc.Server
// activePods is a method for listing active pods on the node
// so the amount of pluginResources requested by existing pods
// could be counted when updating allocated devices
activePods ActivePodsFunc
// sourcesReady provides the readiness of kubelet configuration sources such as apiserver update readiness.
// We use it to determine when we can purge inactive pods from checkpointed state.
sourcesReady config.SourcesReady
// callback is used for updating devices' states in one time call.
// e.g. a new device is advertised, two old devices are deleted and a running device fails.
callback monitorCallback
// healthyDevices contains all of the registered healthy resourceNames and their exported device IDs.
healthyDevices map[string]sets.String
// unhealthyDevices contains all of the unhealthy devices and their exported device IDs.
unhealthyDevices map[string]sets.String
// allocatedDevices contains allocated deviceIds, keyed by resourceName.
allocatedDevices map[string]sets.String
// podDevices contains pod to allocated device mapping.
podDevices podDevices
store utilstore.Store
pluginOpts map[string]*pluginapi.DevicePluginOptions
}下面是核心field的说明：
socketname: 就是kubelet对外暴露的socket名，即 kubelet.sock。
socketdir: device plugins' socket的存放的目录，/var/lib/kubelet/device-plugins/。
endpoints: map对象，key为Resource Name，value为endpoint接口(包括run，stop，allocate，preStartContainer，getDevices，callback，isStoped，StopGracePeriodExpired)，每个endpoint接口对应一个已注册的device plugin，负责与device plugin的gRPC通信及缓存device plugin反馈的device states。
server: Register服务暴露的gRPC Server。
activePods: 用来获取该节点上所有active pods，即non-Terminated状态的Pods。在kubelet的initializeRuntimeDependentModules时会注册activePods Func为如下函数：
// GetActivePods returns non-terminal pods
func (kl *Kubelet) GetActivePods() []*v1.Pod {
allPods := kl.podManager.GetPods()
activePods := kl.filterOutTerminatedPods(allPods)
return activePods
}callback: 是kubelet收到device plugin的ListAndWatch gRCP stream中有devices state变更时的回调函数，包括有新设备增加、旧设备删除、设备状态变化，所以通过ListAndWatch接口的回调方式，可以实现设备的自动发现和热插拔。
type monitorCallback func(resourceName string, added, updated, deleted []pluginapi.Device)
healthyDevices: map对象，key为Resource Name，value为对应的健康的device IDs。
unhealthyDevices: map对象，key为Resource Name，value为对应的不健康的device IDs。
allocatedDevices: map对象，key为Resource Name，value为已经分配出去的device IDs。
podDevices: 记录每个pod中每个容器的device分配情况。
// ContainerAllocateResponse为容器内某个device对应的分配信息，包括注入的环境变量、挂载信息、Annotations。
type ContainerAllocateResponse struct {
Envs map[string]string
Mounts []*Mount
Devices []*DeviceSpec
Annotations map[string]string
}
// deviceAllocateInfo
type deviceAllocateInfo struct {
deviceIds sets.String
allocResp *pluginapi.ContainerAllocateResponse
}
type resourceAllocateInfo map[string]deviceAllocateInfo // Keyed by resourceName.
type containerDevices map[string]resourceAllocateInfo // Keyed by containerName.
type podDevices map[string]containerDevices // Keyed by podUID.store: 是对checkpointData的文件存储(/var/lib/kubelet/device-plugins/kubelet_internal_checkpoint)，具体存储了每个Pod分配的Devices信息PodDeviceEntries, 以及已经注册的Resource Name及对应的Devices IDs。
type checkpointData struct {
PodDeviceEntries []podDevicesCheckpointEntry
RegisteredDevices map[string][]string // key为Resource Name，value为DeviceIDs
}
type podDevicesCheckpointEntry struct {
PodUID string
ContainerName string
ResourceName string
DeviceIDs []string
AllocResp []byte
}
pluginOpts: map对象，key为Resource Name，value为DevicePluginOptions，目前只有一项内容，就是PreStartRequired bool，表示是否在容器启动前要调用device plugin的PreStartContiner接口。在nvidia-k8s-plugin中，PreStartContainer为空实现。
我们再来看看Device Manager的具体创建实现NewManagerImpl。
pkg/kubelet/cm/devicemanager/manager.go:97
// NewManagerImpl creates a new manager.
func NewManagerImpl() (*ManagerImpl, error) {
// 通过/var/lib/kubelet/device-plugins/kubelet.sock与device plugin交互
return newManagerImpl(pluginapi.KubeletSocket)
}
func newManagerImpl(socketPath string) (*ManagerImpl, error) {
glog.V(2).Infof("Creating Device Plugin manager at %s", socketPath)
if socketPath == "" || !filepath.IsAbs(socketPath) {
return nil, fmt.Errorf(errBadSocket+" %v", socketPath)
}
dir, file := filepath.Split(socketPath)
manager := &ManagerImpl{
endpoints: make(map[string]endpoint),
socketname: file,
socketdir: dir,
healthyDevices: make(map[string]sets.String),
unhealthyDevices: make(map[string]sets.String),
allocatedDevices: make(map[string]sets.String),
pluginOpts: make(map[string]*pluginapi.DevicePluginOptions),
podDevices: make(podDevices),
}
manager.callback = manager.genericDeviceUpdateCallback
// The following structs are populated with real implementations in manager.Start()
// Before that, initializes them to perform no-op operations.
manager.activePods = func() []*v1.Pod { return []*v1.Pod{} }
manager.sourcesReady = &sourcesReadyStub{}
var err error
// 在/var/lib/kubelet/device-plugins/目录下创建file store类型的key-value存储文件kubelet_internal_checkpoint，用来作为kubelet的device plugin的checkpoint。
manager.store, err = utilstore.NewFileStore(dir, utilfs.DefaultFs{})
if err != nil {
return nil, fmt.Errorf("failed to initialize device plugin checkpointing store: %+v", err)
}
return manager, nil
}kubelet Device Manager通过/var/lib/kubelet/device-plugins/kubelet.sock与device plugin交互。
注册callback为genericDeviceUpdateCallback，用来处理对应devices的add,delete,update事件。
在/var/lib/kubelet/device-plugins/目录下创建file store类型的key-value存储文件kubelet_internal_checkpoint，用来作为kubelet的device plugin的checkpoint。
当监听到devices add/delete/update事件发生时，会更新到kubelet_internal_checkpoint文件中。
当device plugin的stop time超过grace period time(代码写死为5min，不可配置),会从checkpoint中删除对应的devices。在这个时间范围内，Device Manager会继续缓存该endpoint及对应的devices。
为Container Allocate Devices后，也会将PodDevices更新到checkpoint中。
我们来看看callback的实现genericDeviceUpdateCallback的实现，了解Device Manager是如何处理devices的add/delete/update消息的。
pkg/kubelet/cm/devicemanager/manager.go:134
func (m *ManagerImpl) genericDeviceUpdateCallback(resourceName string, added, updated, deleted []pluginapi.Device) {
kept := append(updated, added...)
m.mutex.Lock()
if _, ok := m.healthyDevices[resourceName]; !ok {
m.healthyDevices[resourceName] = sets.NewString()
}
if _, ok := m.unhealthyDevices[resourceName]; !ok {
m.unhealthyDevices[resourceName] = sets.NewString()
}
for _, dev := range kept {
if dev.Health == pluginapi.Healthy {
m.healthyDevices[resourceName].Insert(dev.ID)
m.unhealthyDevices[resourceName].Delete(dev.ID)
} else {
m.unhealthyDevices[resourceName].Insert(dev.ID)
m.healthyDevices[resourceName].Delete(dev.ID)
}
}
for _, dev := range deleted {
m.healthyDevices[resourceName].Delete(dev.ID)
m.unhealthyDevices[resourceName].Delete(dev.ID)
}
m.mutex.Unlock()
m.writeCheckpoint()
}将callback中收到的devices状态是Healthy，那么将device ID插入到ManagerImpl中healthDevices中，并从unhealthyDevices中删除。
将callback中收到的devices状态是Unhealthy，那么将device ID插入到ManagerImpl中unhealthDevices中，并从healthyDevices中删除。
将device plugin反馈的需要delete的devices从healthDevices和unhealthDevices中一并删除。
将ManagerImpl中的数据更新到checkpoint文件中。
前面把Device Manager的创建流程分析了一下，还涉及到checkpoint和callback的分析。接下来，我们继续对Device Manager的Start流程进行分析。
Device Manager是在containerManagerImpl的Start时启动的。
pkg/kubelet/cm/container_manager_linux.go:527
func (cm *containerManagerImpl) Start(node *v1.Node,
activePods ActivePodsFunc,
sourcesReady config.SourcesReady,
podStatusProvider status.PodStatusProvider,
runtimeService internalapi.RuntimeService) error {
...
// Starts device manager.
if err := cm.deviceManager.Start(devicemanager.ActivePodsFunc(activePods), sourcesReady); err != nil {
return err
}
return nil
}deviceManager.Start的第一个参数是获取该节点的active(non-terminated)Pods的函数。
SourcesReady是用来跟踪kubelet配置的Pod Sources，这些Sources包括：
file: 通过static file创建静态Pods。
http: 通过http接口来获取Pods信息。
api: 从Kubernetes API Server获取Pods信息，是Kubernetes默认的内部机制。
*: 表示包含以上全部的Sources类型。
ManagerIml.Start负责启动Device Manager，对外提供gRPC服务。
pkg/kubelet/cm/devicemanager/manager.go:204
// Start starts the Device Plugin Manager amd start initialization of
// podDevices and allocatedDevices information from checkpoint-ed state and
// starts device plugin registration service.
func (m *ManagerImpl) Start(activePods ActivePodsFunc, sourcesReady config.SourcesReady) error {
m.activePods = activePods
m.sourcesReady = sourcesReady
// Loads in allocatedDevices information from disk.
err := m.readCheckpoint()
...
socketPath := filepath.Join(m.socketdir, m.socketname)
os.MkdirAll(m.socketdir, 0755)
// Removes all stale sockets in m.socketdir. Device plugins can monitor
// this and use it as a signal to re-register with the new Kubelet.
if err := m.removeContents(m.socketdir); err != nil {
glog.Errorf("Fail to clean up stale contents under %s: %+v", m.socketdir, err)
}
s, err := net.Listen("unix", socketPath)
if err != nil {
glog.Errorf(errListenSocket+" %+v", err)
return err
}
m.server = grpc.NewServer([]grpc.ServerOption{}...)
pluginapi.RegisterRegistrationServer(m.server, m)
go m.server.Serve(s)
glog.V(2).Infof("Serving device plugin registration server on %q", socketPath)
return nil
}首先读取checkpoint file中数据，恢复ManagerImpl的相关数据，包括：
podDevices；
allocatedDevices；
healthyDevices；
unhealthyDevices；
endpoints，注意这里会将endpoint的stop time设置为当前时间，意味着kubelet restart后，需要等待device plugin进行re-register后，才认为这些resource是可用的。
然后将/var/lib/kubelet/device-plugins/下面的所有文件清空，当然checkpiont文件除外，也就是清空所有的socket文件，包括自己的kubelet.sock,以及其他所有之前的device plugin的socket文件。device plugin会监控kubelet.sock文件是否被删除，如果删除，则会触发自己的向kubelet重新注册自己。
创建kubelet.sock并启动gRPC Server对外提供gRPC服务，目前只注册了Register服务，用于Device plugin调用进行插件注册。
我们就来看看kubelet Device Manager对外提供的唯一gRPC接口Register。
pkg/kubelet/cm/devicemanager/manager.go:289
// Register registers a device plugin.
func (m *ManagerImpl) Register(ctx context.Context, r *pluginapi.RegisterRequest) (*pluginapi.Empty, error) {
glog.Infof("Got registration request from device plugin with resource name %q", r.ResourceName)
metrics.DevicePluginRegistrationCount.WithLabelValues(r.ResourceName).Inc()
var versionCompatible bool
for _, v := range pluginapi.SupportedVersions {
if r.Version == v {
versionCompatible = true
break
}
}
if !versionCompatible {
errorString := fmt.Sprintf(errUnsupportedVersion, r.Version, pluginapi.SupportedVersions)
glog.Infof("Bad registration request from device plugin with resource name %q: %v", r.ResourceName, errorString)
return &pluginapi.Empty{}, fmt.Errorf(errorString)
}
if !v1helper.IsExtendedResourceName(v1.ResourceName(r.ResourceName)) {
errorString := fmt.Sprintf(errInvalidResourceName, r.ResourceName)
glog.Infof("Bad registration request from device plugin: %v", errorString)
return &pluginapi.Empty{}, fmt.Errorf(errorString)
}
// TODO: for now, always accepts newest device plugin. Later may consider to
// add some policies here, e.g., verify whether an old device plugin with the
// same resource name is still alive to determine whether we want to accept
// the new registration.
go m.addEndpoint(r)
return &pluginapi.Empty{}, nil
}注册请求是device plugin向kubelet发送的，注册请求RegisterRequest为：
type RegisterRequest struct {
Version string // Kubernetes 1.10对应的device plugin api version为v1beta1
Endpoint string // device plugin对应的socket name
ResourceName string
Options *DevicePluginOptions
}这里会检查注册的Resource Name是否符合Extended Resource的规则：
Resource Name不能属于kubernetes.io，得有自己的domain，比如nvidia.com。
Resource Name中不能包含requests.前缀。
对应的Resource value只能是整数值。
调用addEndpoint进行插件注册。
从上面Register的方法中可见，真正插件注册的逻辑是在addEndpoint中实现的。
pkg/kubelet/cm/devicemanager/manager.go:332
func (m *ManagerImpl) addEndpoint(r *pluginapi.RegisterRequest) {
existingDevs := make(map[string]pluginapi.Device)
m.mutex.Lock()
old, ok := m.endpoints[r.ResourceName]
if ok && old != nil {
// Pass devices of previous endpoint into re-registered one,
// to avoid potential orphaned devices upon re-registration
devices := make(map[string]pluginapi.Device)
for _, device := range old.getDevices() {
devices[device.ID] = device
}
existingDevs = devices
}
m.mutex.Unlock()
socketPath := filepath.Join(m.socketdir, r.Endpoint)
e, err := newEndpointImpl(socketPath, r.ResourceName, existingDevs, m.callback)
if err != nil {
glog.Errorf("Failed to dial device plugin with request %v: %v", r, err)
return
}
m.mutex.Lock()
if r.Options != nil {
m.pluginOpts[r.ResourceName] = r.Options
}
// Check for potential re-registration during the initialization of new endpoint,
// and skip updating if re-registration happens.
// TODO: simplify the part once we have a better way to handle registered devices
ext := m.endpoints[r.ResourceName]
if ext != old {
glog.Warningf("Some other endpoint %v is added while endpoint %v is initialized", ext, e)
m.mutex.Unlock()
e.stop()
return
}
// Associates the newly created endpoint with the corresponding resource name.
// Stops existing endpoint if there is any.
m.endpoints[r.ResourceName] = e
glog.V(2).Infof("Registered endpoint %v", e)
m.mutex.Unlock()
if old != nil {
old.stop()
}
go func() {
e.run()
e.stop()
m.mutex.Lock()
if old, ok := m.endpoints[r.ResourceName]; ok && old == e {
m.markResourceUnhealthy(r.ResourceName)
}
glog.V(2).Infof("Unregistered endpoint %v", e)
m.mutex.Unlock()
}()
}首先检查注册的这个device plugin是否已经注册过，如果注册过，则获取已经缓存的devices。
再检查device plugin的socket是否能dial成功，如果dial失败，则说明device plugin没正常启动。如果dial成功，就根据已经缓存的devices重新初始化Endpoint，EndpointImpl的定义如下：
type endpointImpl struct {
client pluginapi.DevicePluginClient
clientConn *grpc.ClientConn
socketPath string
resourceName string
stopTime time.Time
devices map[string]pluginapi.Device
mutex sync.Mutex
cb monitorCallback
}为了防止在EndpointImpl重新初始化的过程中device plugin进行re-register，初始化完成后再次获取缓存中该device plugin的Endpoint，并与初始化之前的Endpoint对象进行比对:
如果不是同一个对象，则说明在初始化过程中发生了re-register，那么就invoke Endpoint的stop接口，关闭gRPC连接，并设置Endpoint的stopTime为当前时间，Register流程以失败结束。
否则继续后面流程。
如果该device plugin之前注册过，那么再重新调用Endpoint的run()启动之前，先调用Endpoint的stop关闭gRPC连接，并设置Endpoint的stopTime为当前时间。
然后启动golang协程执行Endpoint的run()，在run方法中:
调用device plugin的ListAndWatch gRPC接口，通过长连接持续获取ListAndWatch gRPC stream，
从stream流中获取的devices与Endpoint中缓存的devices进行比对，得到需要add/delete/update的devices，
然后调用Endpoint的callback（也就是ManagerImpl注册的callback方法genericDeviceUpdateCallback）进行Device Manager的缓存更新并写到checkpoint文件中。
直到与device plugin的gRPC连接发生errListAndWatch错误，跳出持续获取stream的死循环，然后调用Endpoint的stop关闭gRPC连接，并设置Endpoint的stopTime为当前时间。
invoke stop后，再标记该device plugin对应的所有devices为unhealthy，即设置healthyDevices为空， 所有原来healthy的devices都加到unhealthyDevices中，此时表示注册失败。
kubelet在NewMainKubelet中会注册一系列的Pod Admit Handler，当有Pod需要创建的时，都会先调用这些Pod Admit Handler进行处理，其中klet.containerManager.UpdatePluginResources就是kubelet Device Manager为Pod分配devices的。
pkg/kubelet/kubelet.go:893
func NewMainKubelet( ... ) (*Kubelet, error) {
...
klet.admitHandlers.AddPodAdmitHandler(lifecycle.NewPredicateAdmitHandler(klet.getNodeAnyWay, criticalPodAdmissionHandler, klet.containerManager.UpdatePluginResources))
...
}
pkg/kubelet/cm/container_manager_linux.go:618
func (cm *containerManagerImpl) UpdatePluginResources(node *schedulercache.NodeInfo, attrs *lifecycle.PodAdmitAttributes) error {
return cm.deviceManager.Allocate(node, attrs)
}kubelet在创建Pod前，会invoke Device Manager的Allocate方法，为Pod中的每个Container请求分配对应的devices，kubelet会将请求转发到对应的Endpoint的Allocate方法， 然后请求会到对应的device plugin进行处理。
pkg/kubelet/cm/devicemanager/manager.go:259
func (m *ManagerImpl) Allocate(node *schedulercache.NodeInfo, attrs *lifecycle.PodAdmitAttributes) error {
pod := attrs.Pod
devicesToReuse := make(map[string]sets.String)
// TODO: Reuse devices between init containers and regular containers.
for _, container := range pod.Spec.InitContainers {
if err := m.allocateContainerResources(pod, &container, devicesToReuse); err != nil {
return err
}
m.podDevices.addContainerAllocatedResources(string(pod.UID), container.Name, devicesToReuse)
}
for _, container := range pod.Spec.Containers {
if err := m.allocateContainerResources(pod, &container, devicesToReuse); err != nil {
return err
}
m.podDevices.removeContainerAllocatedResources(string(pod.UID), container.Name, devicesToReuse)
}
m.mutex.Lock()
defer m.mutex.Unlock()
// quick return if no pluginResources requested
if _, podRequireDevicePluginResource := m.podDevices[string(pod.UID)]; !podRequireDevicePluginResource {
return nil
}
m.sanitizeNodeAllocatable(node)
return nil
}调用allocateContainerResources为Pod中的init container分配devices，并更新ManagerImpl中PodDevices缓存；
调用allocateContainerResources为Pod中的regular container分配devices，并更新ManagerImpl中PodDevices缓存；
调用sanitizeNodeAllocatable更新scheduler cache中Node对应Resource Name的Allocatable Resource；
pkg/kubelet/cm/devicemanager/manager.go:608
func (m *ManagerImpl) allocateContainerResources(pod *v1.Pod, container *v1.Container, devicesToReuse map[string]sets.String) error {
podUID := string(pod.UID)
contName := container.Name
allocatedDevicesUpdated := false
// Extended resources are not allowed to be overcommitted.
// Since device plugin advertises extended resources,
// therefore Requests must be equal to Limits and iterating
// over the Limits should be sufficient.
for k, v := range container.Resources.Limits {
resource := string(k)
needed := int(v.Value())
glog.V(3).Infof("needs %d %s", needed, resource)
if !m.isDevicePluginResource(resource) {
continue
}
// Updates allocatedDevices to garbage collect any stranded resources
// before doing the device plugin allocation.
if !allocatedDevicesUpdated {
m.updateAllocatedDevices(m.activePods())
allocatedDevicesUpdated = true
}
allocDevices, err := m.devicesToAllocate(podUID, contName, resource, needed, devicesToReuse[resource])
if err != nil {
return err
}
if allocDevices == nil || len(allocDevices) <= 0 {
continue
}
startRPCTime := time.Now()
m.mutex.Lock()
e, ok := m.endpoints[resource]
m.mutex.Unlock()
if !ok {
m.mutex.Lock()
m.allocatedDevices = m.podDevices.devices()
m.mutex.Unlock()
return fmt.Errorf("Unknown Device Plugin %s", resource)
}
devs := allocDevices.UnsortedList()
glog.V(3).Infof("Making allocation request for devices %v for device plugin %s", devs, resource)
resp, err := e.allocate(devs)
metrics.DevicePluginAllocationLatency.WithLabelValues(resource).Observe(metrics.SinceInMicroseconds(startRPCTime))
if err != nil {
m.mutex.Lock()
m.allocatedDevices = m.podDevices.devices()
m.mutex.Unlock()
return err
}
// Update internal cached podDevices state.
m.mutex.Lock()
m.podDevices.insert(podUID, contName, resource, allocDevices, resp.ContainerResponses[0])
m.mutex.Unlock()
}
// Checkpoints device to container allocation information.
return m.writeCheckpoint()
}device plugin提供的Resource属于Kubernetes Extended Resources，所以其Resource QoS只能是Guaranted。
每次在为Pod分配devices之前，都去检查一下此时的active pods，并与podDevices缓存中的pods进行比对，将已经terminated的Pods的devices从podDevices中删除，即进行了devices的GC操作。
从healthyDevices中随机分配对应数量的devices给该Pod，并注意更新allocatedDevices，否则会导致一个device被分配给多个Pod。
拿到devices后，就调用Endpoint的Allocate方法（进而调用对应device plugin的Allocate gRPC Service），device plugin返回ContainerAllocateResponse(包括注入的环境变量、挂载信息、Annotations)。
更新podDevices缓存信息，并将ManagerImpl中缓存数据更新到checkpoint文件中。
思考：当init container结束后，对应分配的devices会被释放吗？ 目前还不会释放devices，在Allocate前只会回收Terminated Pods的devices，并没有回收init container的devices。要优化这个也是比较简单的，只要修改上面代码中updateAllocatedDevices方法内的逻辑就行了，增加init container的devices回收逻辑。
所以当前版本最好不会要在init container中使用devices，虽然这种场景几乎不存在。
当kubelet更新node status时会调用GetCapacity更新device plugins对应的Resource信息。
pkg/kubelet/kubelet_node_status.go:599
func (kl *Kubelet) setNodeStatusMachineInfo(node *v1.Node) {
...
devicePluginCapacity, devicePluginAllocatable, removedDevicePlugins = kl.containerManager.GetDevicePluginResourceCapacity()
...
}
pkg/kubelet/cm/container_manager_linux.go:881
func (cm *containerManagerImpl) GetDevicePluginResourceCapacity() (v1.ResourceList, v1.ResourceList, []string) {
return cm.deviceManager.GetCapacity()
}下面是GetCapacity的具体代码实现，逻辑很简单：
检测healthyDevices对应的device plugin是否已经从缓存中删除或者已经停止超过5min，如果满足以上条件之一，则从endpoints和healthyDevices缓存中删除这些devices。
检测unhealthyDevices对应的device plugin是否已经从缓存中删除或者已经停止超过5min，如果满足以上条件之一，则从endpoints和unhealthyDevices缓存中删除这些devices。
如果缓存发生变化，则更新到checkpoint文件中。
pkg/kubelet/cm/devicemanager/manager.go:414
func (m *ManagerImpl) GetCapacity() (v1.ResourceList, v1.ResourceList, []string) {
needsUpdateCheckpoint := false
var capacity = v1.ResourceList{}
var allocatable = v1.ResourceList{}
deletedResources := sets.NewString()
m.mutex.Lock()
for resourceName, devices := range m.healthyDevices {
e, ok := m.endpoints[resourceName]
if (ok && e.stopGracePeriodExpired()) || !ok {
if !ok {
glog.Errorf("unexpected: healthyDevices and endpoints are out of sync")
}
delete(m.endpoints, resourceName)
delete(m.healthyDevices, resourceName)
deletedResources.Insert(resourceName)
needsUpdateCheckpoint = true
} else {
capacity[v1.ResourceName(resourceName)] = *resource.NewQuantity(int64(devices.Len()), resource.DecimalSI)
allocatable[v1.ResourceName(resourceName)] = *resource.NewQuantity(int64(devices.Len()), resource.DecimalSI)
}
}
for resourceName, devices := range m.unhealthyDevices {
e, ok := m.endpoints[resourceName]
if (ok && e.stopGracePeriodExpired()) || !ok {
if !ok {
glog.Errorf("unexpected: unhealthyDevices and endpoints are out of sync")
}
delete(m.endpoints, resourceName)
delete(m.unhealthyDevices, resourceName)
deletedResources.Insert(resourceName)
needsUpdateCheckpoint = true
} else {
capacityCount := capacity[v1.ResourceName(resourceName)]
unhealthyCount := *resource.NewQuantity(int64(devices.Len()), resource.DecimalSI)
capacityCount.Add(unhealthyCount)
capacity[v1.ResourceName(resourceName)] = capacityCount
}
}
m.mutex.Unlock()
if needsUpdateCheckpoint {
m.writeCheckpoint()
}
return capacity, allocatable, deletedResources.UnsortedList()
}GetCapacity更新NodeStatus如下数据：
registered device plugin resource Capacity
registered device plugin resource Allocatable
previously registered resources that are no longer active
在kubelet的GetResource中，会调用DeviceManager的GetDeviceRunContainerOptions，并将这些options添加到kubecontainer.RunContainerOptions中。RunContainerOptions包括Envs、Mounts、Devices、PortMappings、Annotations等信息。
pkg/kubelet/cm/container_manager_linux.go:601
// TODO: move the GetResources logic to PodContainerManager.
func (cm *containerManagerImpl) GetResources(pod *v1.Pod, container *v1.Container) (*kubecontainer.RunContainerOptions, error) {
opts := &kubecontainer.RunContainerOptions{}
// Allocate should already be called during predicateAdmitHandler.Admit(),
// just try to fetch device runtime information from cached state here
devOpts, err := cm.deviceManager.GetDeviceRunContainerOptions(pod, container)
if err != nil {
return nil, err
} else if devOpts == nil {
return opts, nil
}
opts.Devices = append(opts.Devices, devOpts.Devices...)
opts.Mounts = append(opts.Mounts, devOpts.Mounts...)
opts.Envs = append(opts.Envs, devOpts.Envs...)
opts.Annotations = append(opts.Annotations, devOpts.Annotations...)
return opts, nil
}Device Manager的GetDeviceRunContainerOptions会根据pluginOpts的PreStartRequired是否为true，决定是否调用device plugin的PreStartContainer gRPC Service。
注意：如果某个device plugin的PreStartRequired为true，那么需要注册kubelet Device Manager调用device plugin的PreStartContainer接口的超时时间是30s，即30s内必须完成PreStartContainer的逻辑并返回。