初始化运行时服务

初始化运行时服务调用:

err = kubelet.PreInitRuntimeService(&s.KubeletConfiguration,
        kubeDeps, &s.ContainerRuntimeOptions,
        s.ContainerRuntime,
        s.RuntimeCgroups,
        s.RemoteRuntimeEndpoint,
        s.RemoteImageEndpoint,
        s.NonMasqueradeCIDR)
if err != nil {
    return err
}

PreInitRuntimeService函数解析

func PreInitRuntimeService(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
    kubeDeps *Dependencies,
    crOptions *config.ContainerRuntimeOptions,
    containerRuntime string,
    runtimeCgroups string,
    remoteRuntimeEndpoint string,
    remoteImageEndpoint string,
    nonMasqueradeCIDR string) error {
    if remoteRuntimeEndpoint != "" {
        // remoteImageEndpoint is same as remoteRuntimeEndpoint if not explicitly specified
        if remoteImageEndpoint == "" {
            remoteImageEndpoint = remoteRuntimeEndpoint
        }
    }

    switch containerRuntime {
    case kubetypes.DockerContainerRuntime:
        // TODO: These need to become arguments to a standalone docker shim.
        pluginSettings := dockershim.NetworkPluginSettings{
            HairpinMode:        kubeletconfiginternal.HairpinMode(kubeCfg.HairpinMode),
            NonMasqueradeCIDR:  nonMasqueradeCIDR,
            PluginName:         crOptions.NetworkPluginName,
            PluginConfDir:      crOptions.CNIConfDir,
            PluginBinDirString: crOptions.CNIBinDir,
            PluginCacheDir:     crOptions.CNICacheDir,
            MTU:                int(crOptions.NetworkPluginMTU),
        }

        // Create and start the CRI shim running as a grpc server.
        streamingConfig := getStreamingConfig(kubeCfg, kubeDeps, crOptions)
        ds, err := dockershim.NewDockerService(kubeDeps.DockerClientConfig, crOptions.PodSandboxImage, streamingConfig,
            &pluginSettings, runtimeCgroups, kubeCfg.CgroupDriver, crOptions.DockershimRootDirectory, !crOptions.RedirectContainerStreaming)
        if err != nil {
            return err
        }
        if crOptions.RedirectContainerStreaming {
            kubeDeps.criHandler = ds
        }

        // The unix socket for kubelet <-> dockershim communication, dockershim start before runtime service init.
        klog.V(5).Infof("RemoteRuntimeEndpoint: %q, RemoteImageEndpoint: %q",
            remoteRuntimeEndpoint,
            remoteImageEndpoint)
        klog.V(2).Infof("Starting the GRPC server for the docker CRI shim.")
        dockerServer := dockerremote.NewDockerServer(remoteRuntimeEndpoint, ds)
        if err := dockerServer.Start(); err != nil {
            return err
        }

        // Create dockerLegacyService when the logging driver is not supported.
        supported, err := ds.IsCRISupportedLogDriver()
        if err != nil {
            return err
        }
        if !supported {
            kubeDeps.dockerLegacyService = ds
        }
    case kubetypes.RemoteContainerRuntime:
        // No-op.
        break
    default:
        return fmt.Errorf("unsupported CRI runtime: %q", containerRuntime)
    }

    var err error
    if kubeDeps.RemoteRuntimeService, err = remote.NewRemoteRuntimeService(remoteRuntimeEndpoint, kubeCfg.RuntimeRequestTimeout.Duration); err != nil {
        return err
    }
    if kubeDeps.RemoteImageService, err = remote.NewRemoteImageService(remoteImageEndpoint, kubeCfg.RuntimeRequestTimeout.Duration); err != nil {
        return err
    }

    kubeDeps.useLegacyCadvisorStats = cadvisor.UsingLegacyCadvisorStats(containerRuntime, remoteRuntimeEndpoint)

    return nil
}

主要做了以下几件事：

1. 初始化网络插件
2. 创建并启动CRI shim作为grpc服务端运行