ceph-csi源码分析（3）-rbd driver-服务入口分析

更多ceph-csi其他源码分析，请查看下面这篇博文：kubernetes ceph-csi分析目录导航

ceph-csi源码分析（3）-rbd driver-服务入口分析

当ceph-csi组件启动时指定的driver type为rbd时，会启动rbd driver相关的服务。然后再根据controllerserver、nodeserver的参数配置，决定启动ControllerServer与IdentityServer，或NodeServer与IdentityServer。

基于tag v3.0.0

https://github.com/ceph/ceph-csi/releases/tag/v3.0.0

rbd driver分析将分为4个部分，分别是服务入口分析、controllerserver分析、nodeserver分析与IdentityServer分析。

这节先进行服务入口分析。

服务入口分析

main

分析入口，根据不同的type，初始化对应的driver，并调用driver的启动方法。

    ......
    switch conf.Vtype {
	case rbdType:
		validateCloneDepthFlag(&conf)
		validateMaxSnaphostFlag(&conf)
		driver := rbd.NewDriver()
		driver.Run(&conf)

	case cephfsType:
		driver := cephfs.NewDriver()
		driver.Run(&conf)

	case livenessType:
		liveness.Run(&conf)

	default:
		klog.Fatalln("invalid volume type", conf.Vtype) // calls exit
	}
	......

Run（rbd）

rbd driver的启动方法。

主要逻辑：
（1）创建ceph.conf文件用于执行cli命令；
（2）创建CSIDriver ，注册driver对外的服务能力，即拥有哪些功能；
（3）创建IdentityServer；
（4）根据启动参数配置，决定创建nodeserver，还是创建controllerserver；
（5）创建grpc server，并注册前面创建的几个server；
（6）启动grpc server。

// internal/rbd/driver.go

type Driver struct {
	cd *csicommon.CSIDriver

	ids *IdentityServer
	ns  *NodeServer
	cs  *ControllerServer
}

// Run start a non-blocking grpc controller,node and identityserver for
// rbd CSI driver which can serve multiple parallel requests.
func (r *Driver) Run(conf *util.Config) {
	var err error
	var topology map[string]string
    
    // 创建ceph.conf文件用于执行cli命令
	// Create ceph.conf for use with CLI commands
	if err = util.WriteCephConfig(); err != nil {
		klog.Fatalf("failed to write ceph configuration file (%v)", err)
	}

	// Use passed in instance ID, if provided for omap suffix naming
	if conf.InstanceID != "" {
		CSIInstanceID = conf.InstanceID
	}

	// update clone soft and hard limit
	rbdHardMaxCloneDepth = conf.RbdHardMaxCloneDepth
	rbdSoftMaxCloneDepth = conf.RbdSoftMaxCloneDepth
	skipForceFlatten = conf.SkipForceFlatten
	maxSnapshotsOnImage = conf.MaxSnapshotsOnImage
	// Create instances of the volume and snapshot journal
	volJournal = journal.NewCSIVolumeJournal(CSIInstanceID)
	snapJournal = journal.NewCSISnapshotJournal(CSIInstanceID)
    
    // 创建CSIDriver ，注册driver能力
	// Initialize default library driver
	r.cd = csicommon.NewCSIDriver(conf.DriverName, util.DriverVersion, conf.NodeID)
	if r.cd == nil {
		klog.Fatalln("Failed to initialize CSI Driver.")
	}
	if conf.IsControllerServer || !conf.IsNodeServer {
		r.cd.AddControllerServiceCapabilities([]csi.ControllerServiceCapability_RPC_Type{
			csi.ControllerServiceCapability_RPC_CREATE_DELETE_VOLUME,
			csi.ControllerServiceCapability_RPC_CREATE_DELETE_SNAPSHOT,
			csi.ControllerServiceCapability_RPC_CLONE_VOLUME,
			csi.ControllerServiceCapability_RPC_EXPAND_VOLUME,
		})
		// We only support the multi-writer option when using block, but it's a supported capability for the plugin in general
		// In addition, we want to add the remaining modes like MULTI_NODE_READER_ONLY,
		// MULTI_NODE_SINGLE_WRITER etc, but need to do some verification of RO modes first
		// will work those as follow up features
		r.cd.AddVolumeCapabilityAccessModes(
			[]csi.VolumeCapability_AccessMode_Mode{csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER,
				csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER})
	}
    
    // 创建IdentityServer
	// Create GRPC servers
	r.ids = NewIdentityServer(r.cd)
    
    // 创建nodeserver
	if conf.IsNodeServer {
		topology, err = util.GetTopologyFromDomainLabels(conf.DomainLabels, conf.NodeID, conf.DriverName)
		if err != nil {
			klog.Fatalln(err)
		}
		r.ns, err = NewNodeServer(r.cd, conf.Vtype, topology)
		if err != nil {
			klog.Fatalf("failed to start node server, err %v\n", err)
		}
	}
    
    // 创建controllerserver
	if conf.IsControllerServer {
		r.cs = NewControllerServer(r.cd)
	}
	if !conf.IsControllerServer && !conf.IsNodeServer {
		topology, err = util.GetTopologyFromDomainLabels(conf.DomainLabels, conf.NodeID, conf.DriverName)
		if err != nil {
			klog.Fatalln(err)
		}
		r.ns, err = NewNodeServer(r.cd, conf.Vtype, topology)
		if err != nil {
			klog.Fatalf("failed to start node server, err %v\n", err)
		}
		r.cs = NewControllerServer(r.cd)
	}
    
    // 创建grpc server，注册前面创建的几个server并启动grpc server
	s := csicommon.NewNonBlockingGRPCServer()
	s.Start(conf.Endpoint, conf.HistogramOption, r.ids, r.cs, r.ns, conf.EnableGRPCMetrics)
	if conf.EnableGRPCMetrics {
		klog.Warning("EnableGRPCMetrics is deprecated")
		go util.StartMetricsServer(conf)
	}
	s.Wait()
}