package libpod import ( "fmt" "net" "path/filepath" "time" "github.com/containernetworking/cni/pkg/types" cnitypes "github.com/containernetworking/cni/pkg/types/current" "github.com/containernetworking/plugins/pkg/ns" "github.com/containers/storage" "github.com/cri-o/ocicni/pkg/ocicni" spec "github.com/opencontainers/runtime-spec/specs-go" "github.com/pkg/errors" "github.com/ulule/deepcopier" ) // ContainerStatus represents the current state of a container type ContainerStatus int const ( // ContainerStateUnknown indicates that the container is in an error // state where information about it cannot be retrieved ContainerStateUnknown ContainerStatus = iota // ContainerStateConfigured indicates that the container has had its // storage configured but it has not been created in the OCI runtime ContainerStateConfigured ContainerStatus = iota // ContainerStateCreated indicates the container has been created in // the OCI runtime but not started ContainerStateCreated ContainerStatus = iota // ContainerStateRunning indicates the container is currently executing ContainerStateRunning ContainerStatus = iota // ContainerStateStopped indicates that the container was running but has // exited ContainerStateStopped ContainerStatus = iota // ContainerStatePaused indicates that the container has been paused ContainerStatePaused ContainerStatus = iota ) // CgroupfsDefaultCgroupParent is the cgroup parent for CGroupFS in libpod const CgroupfsDefaultCgroupParent = "/libpod_parent" // SystemdDefaultCgroupParent is the cgroup parent for the systemd cgroup // manager in libpod const SystemdDefaultCgroupParent = "system.slice" // LinuxNS represents a Linux namespace type LinuxNS int const ( // InvalidNS is an invalid namespace InvalidNS LinuxNS = iota // IPCNS is the IPC namespace IPCNS LinuxNS = iota // MountNS is the mount namespace MountNS LinuxNS = iota // NetNS is the network namespace NetNS LinuxNS = iota // PIDNS is the PID namespace PIDNS LinuxNS = iota // UserNS is the user namespace UserNS LinuxNS = iota // UTSNS is the UTS namespace UTSNS LinuxNS = iota // CgroupNS is the CGroup namespace CgroupNS LinuxNS = iota ) // String returns a string representation of a Linux namespace // It is guaranteed to be the name of the namespace in /proc for valid ns types func (ns LinuxNS) String() string { switch ns { case InvalidNS: return "invalid" case IPCNS: return "ipc" case MountNS: return "mnt" case NetNS: return "net" case PIDNS: return "pid" case UserNS: return "user" case UTSNS: return "uts" case CgroupNS: return "cgroup" default: return "unknown" } } // Container is a single OCI container // ffjson: skip type Container struct { config *ContainerConfig state *containerState // Batched indicates that a container has been locked as part of a // Batch() operation // Functions called on a batched container will not lock or sync batched bool valid bool lock storage.Locker runtime *Runtime } // containerState contains the current state of the container // It is stored on disk in a tmpfs and recreated on reboot type containerState struct { // The current state of the running container State ContainerStatus `json:"state"` // The path to the JSON OCI runtime spec for this container ConfigPath string `json:"configPath,omitempty"` // RunDir is a per-boot directory for container content RunDir string `json:"runDir,omitempty"` // DestinationRunDir is where the files in RunDir will be accessible for the container. // It is different than RunDir when using userNS DestinationRunDir string `json:"destinationRunDir,omitempty"` // Mounted indicates whether the container's storage has been mounted // for use Mounted bool `json:"mounted,omitempty"` // Mountpoint contains the path to the container's mounted storage as given // by containers/storage. It can be different than RealMountpoint when // usernamespaces are used Mountpoint string `json:"mountPoint,omitempty"` // RealMountpoint contains the path to the container's mounted storage RealMountpoint string `json:"realMountPoint,omitempty"` // StartedTime is the time the container was started StartedTime time.Time `json:"startedTime,omitempty"` // FinishedTime is the time the container finished executing FinishedTime time.Time `json:"finishedTime,omitempty"` // ExitCode is the exit code returned when the container stopped ExitCode int32 `json:"exitCode,omitempty"` // OOMKilled indicates that the container was killed as it ran out of // memory OOMKilled bool `json:"oomKilled,omitempty"` // PID is the PID of a running container PID int `json:"pid,omitempty"` // NetNSPath is the path of the container's network namespace // Will only be set if config.CreateNetNS is true, or the container was // told to join another container's network namespace NetNS ns.NetNS `json:"-"` // ExecSessions contains active exec sessions for container // Exec session ID is mapped to PID of exec process ExecSessions map[string]*ExecSession `json:"execSessions,omitempty"` // IPs contains IP addresses assigned to the container // Only populated if we created a network namespace for the container, // and the network namespace is currently active IPs []*cnitypes.IPConfig `json:"ipAddresses,omitempty"` // Routes contains network routes present in the container // Only populated if we created a network namespace for the container, // and the network namespace is currently active Routes []*types.Route `json:"routes,omitempty"` // BindMounts contains files that will be bind-mounted into the // container when it is mounted. // These include /etc/hosts and /etc/resolv.conf // This maps the path the file will be mounted to in the container to // the path of the file on disk outside the container BindMounts map[string]string `json:"bindMounts,omitempty"` // UserNSRoot is the directory used as root for the container when using // user namespaces. UserNSRoot string `json:"userNSRoot,omitempty"` // ExtensionStageHooks holds hooks which will be executed by libpod // and not delegated to the OCI runtime. ExtensionStageHooks map[string][]spec.Hook `json:"extensionStageHooks,omitempty"` } // ExecSession contains information on an active exec session type ExecSession struct { ID string `json:"id"` Command []string `json:"command"` PID int `json:"pid"` } // ContainerConfig contains all information that was used to create the // container. It may not be changed once created. // It is stored, read-only, on disk type ContainerConfig struct { Spec *spec.Spec `json:"spec"` ID string `json:"id"` Name string `json:"name"` // Full ID of the pood the container belongs to Pod string `json:"pod,omitempty"` // TODO consider breaking these subsections up into smaller structs // UID/GID mappings used by the storage IDMappings storage.IDMappingOptions `json:"idMappingsOptions,omitempty"` // Information on the image used for the root filesystem/ RootfsImageID string `json:"rootfsImageID,omitempty"` RootfsImageName string `json:"rootfsImageName,omitempty"` // Rootfs to use for the container, this conflicts with RootfsImageID Rootfs string `json:"rootfs,omitempty"` // Whether to mount volumes specified in the image. ImageVolumes bool `json:"imageVolumes"` // Src path to be mounted on /dev/shm in container. ShmDir string `json:"ShmDir,omitempty"` // Size of the container's SHM. ShmSize int64 `json:"shmSize"` // Static directory for container content that will persist across // reboot. StaticDir string `json:"staticDir"` // Mounts list contains all additional mounts into the container rootfs. // These include the SHM mount. // These must be unmounted before the container's rootfs is unmounted. Mounts []string `json:"mounts,omitempty"` // Security Config // Whether the container is privileged Privileged bool `json:"privileged"` // SELinux process label for container ProcessLabel string `json:"ProcessLabel,omitempty"` // SELinux mount label for root filesystem MountLabel string `json:"MountLabel,omitempty"` // User and group to use in the container // Can be specified by name or UID/GID User string `json:"user,omitempty"` // Additional groups to add Groups []string `json:"groups,omitempty"` // Namespace Config // IDs of container to share namespaces with // NetNsCtr conflicts with the CreateNetNS bool // These containers are considered dependencies of the given container // They must be started before the given container is started IPCNsCtr string `json:"ipcNsCtr,omitempty"` MountNsCtr string `json:"mountNsCtr,omitempty"` NetNsCtr string `json:"netNsCtr,omitempty"` PIDNsCtr string `json:"pidNsCtr,omitempty"` UserNsCtr string `json:"userNsCtr,omitempty"` UTSNsCtr string `json:"utsNsCtr,omitempty"` CgroupNsCtr string `json:"cgroupNsCtr,omitempty"` // IDs of dependency containers. // These containers must be started before this container is started. Dependencies []string // Network Config // CreateNetNS indicates that libpod should create and configure a new // network namespace for the container // This cannot be set if NetNsCtr is also set CreateNetNS bool `json:"createNetNS"` // PortMappings are the ports forwarded to the container's network // namespace // These are not used unless CreateNetNS is true PortMappings []ocicni.PortMapping `json:"portMappings,omitempty"` // DNS servers to use in container resolv.conf // Will override servers in host resolv if set DNSServer []net.IP `json:"dnsServer,omitempty"` // DNS Search domains to use in container resolv.conf // Will override search domains in host resolv if set DNSSearch []string `json:"dnsSearch,omitempty"` // DNS options to be set in container resolv.conf // With override options in host resolv if set DNSOption []string `json:"dnsOption,omitempty"` // Hosts to add in container // Will be appended to host's host file HostAdd []string `json:"hostsAdd,omitempty"` // Image Config // UserVolumes contains user-added volume mounts in the container. // These will not be added to the container's spec, as it is assumed // they are already present in the spec given to Libpod. Instead, it is // used when committing containers to generate the VOLUMES field of the // image that is created, and for triggering some OCI hooks which do not // fire unless user-added volume mounts are present. UserVolumes []string `json:"userVolumes,omitempty"` // Entrypoint is the container's entrypoint. // It is not used in spec generation, but will be used when the // container is committed to populate the entrypoint of the new image. Entrypoint []string `json:"entrypoint,omitempty"` // Command is the container's command. // It is not used in spec generation, but will be used when the // container is committed to populate the command of the new image. Command []string `json:"command,omitempty"` // Misc Options // Whether to keep container STDIN open Stdin bool `json:"stdin,omitempty"` // Labels is a set of key-value pairs providing additional information // about a container Labels map[string]string `json:"labels,omitempty"` // StopSignal is the signal that will be used to stop the container StopSignal uint `json:"stopSignal,omitempty"` // StopTimeout is the signal that will be used to stop the container StopTimeout uint `json:"stopTimeout,omitempty"` // Time container was created CreatedTime time.Time `json:"createdTime"` // Cgroup parent of the container CgroupParent string `json:"cgroupParent"` // LogPath log location LogPath string `json:"logPath"` // File containing the conmon PID ConmonPidFile string `json:"conmonPidFile,omitempty"` // TODO log options for log drivers PostConfigureNetNS bool `json:"postConfigureNetNS"` } // ContainerStatus returns a string representation for users // of a container state func (t ContainerStatus) String() string { switch t { case ContainerStateUnknown: return "unknown" case ContainerStateConfigured: return "configured" case ContainerStateCreated: return "created" case ContainerStateRunning: return "running" case ContainerStateStopped: return "exited" case ContainerStatePaused: return "paused" } return "bad state" } // Config accessors // Unlocked // Config returns the configuration used to create the container func (c *Container) Config() *ContainerConfig { returnConfig := new(ContainerConfig) deepcopier.Copy(c.config).To(returnConfig) return returnConfig } // Spec returns the container's OCI runtime spec // The spec returned is the one used to create the container. The running // spec may differ slightly as mounts are added based on the image func (c *Container) Spec() *spec.Spec { returnSpec := new(spec.Spec) deepcopier.Copy(c.config.Spec).To(returnSpec) return returnSpec } // ID returns the container's ID func (c *Container) ID() string { return c.config.ID } // Name returns the container's name func (c *Container) Name() string { return c.config.Name } // PodID returns the full ID of the pod the container belongs to, or "" if it // does not belong to a pod func (c *Container) PodID() string { return c.config.Pod } // Image returns the ID and name of the image used as the container's rootfs func (c *Container) Image() (string, string) { return c.config.RootfsImageID, c.config.RootfsImageName } // ImageVolumes returns whether the container is configured to create // persistent volumes requested by the image func (c *Container) ImageVolumes() bool { return c.config.ImageVolumes } // ShmDir returns the sources path to be mounted on /dev/shm in container func (c *Container) ShmDir() string { return c.config.ShmDir } // ShmSize returns the size of SHM device to be mounted into the container func (c *Container) ShmSize() int64 { return c.config.ShmSize } // StaticDir returns the directory used to store persistent container files func (c *Container) StaticDir() string { return c.config.StaticDir } // Privileged returns whether the container is privileged func (c *Container) Privileged() bool { return c.config.Privileged } // ProcessLabel returns the selinux ProcessLabel of the container func (c *Container) ProcessLabel() string { return c.config.ProcessLabel } // MountLabel returns the SELinux mount label of the container func (c *Container) MountLabel() string { return c.config.MountLabel } // User returns the user who the container is run as func (c *Container) User() string { return c.config.User } // Dependencies gets the containers this container depends upon func (c *Container) Dependencies() []string { // Collect in a map first to remove dupes dependsCtrs := map[string]bool{} // First add all namespace containers if c.config.IPCNsCtr != "" { dependsCtrs[c.config.IPCNsCtr] = true } if c.config.MountNsCtr != "" { dependsCtrs[c.config.MountNsCtr] = true } if c.config.NetNsCtr != "" { dependsCtrs[c.config.NetNsCtr] = true } if c.config.PIDNsCtr != "" { dependsCtrs[c.config.NetNsCtr] = true } if c.config.UserNsCtr != "" { dependsCtrs[c.config.UserNsCtr] = true } if c.config.UTSNsCtr != "" { dependsCtrs[c.config.UTSNsCtr] = true } if c.config.CgroupNsCtr != "" { dependsCtrs[c.config.CgroupNsCtr] = true } // Add all generic dependencies for _, id := range c.config.Dependencies { dependsCtrs[id] = true } if len(dependsCtrs) == 0 { return []string{} } depends := make([]string, 0, len(dependsCtrs)) for ctr := range dependsCtrs { depends = append(depends, ctr) } return depends } // NewNetNS returns whether the container will create a new network namespace func (c *Container) NewNetNS() bool { return c.config.CreateNetNS } // PortMappings returns the ports that will be mapped into a container if // a new network namespace is created // If NewNetNS() is false, this value is unused func (c *Container) PortMappings() []ocicni.PortMapping { return c.config.PortMappings } // DNSServers returns DNS servers that will be used in the container's // resolv.conf // If empty, DNS server from the host's resolv.conf will be used instead func (c *Container) DNSServers() []net.IP { return c.config.DNSServer } // DNSSearch returns the DNS search domains that will be used in the container's // resolv.conf // If empty, DNS Search domains from the host's resolv.conf will be used instead func (c *Container) DNSSearch() []string { return c.config.DNSSearch } // DNSOption returns the DNS options that will be used in the container's // resolv.conf // If empty, options from the host's resolv.conf will be used instead func (c *Container) DNSOption() []string { return c.config.DNSOption } // HostsAdd returns hosts that will be added to the container's hosts file // The host system's hosts file is used as a base, and these are appended to it func (c *Container) HostsAdd() []string { return c.config.HostAdd } // UserVolumes returns user-added volume mounts in the container. // These are not added to the spec, but are used during image commit and to // trigger some OCI hooks. func (c *Container) UserVolumes() []string { volumes := make([]string, 0, len(c.config.UserVolumes)) for _, vol := range c.config.UserVolumes { volumes = append(volumes, vol) } return volumes } // Entrypoint is the container's entrypoint. // This is not added to the spec, but is instead used during image commit. func (c *Container) Entrypoint() []string { entrypoint := make([]string, 0, len(c.config.Entrypoint)) for _, str := range c.config.Entrypoint { entrypoint = append(entrypoint, str) } return entrypoint } // Command is the container's command // This is not added to the spec, but is instead used during image commit func (c *Container) Command() []string { command := make([]string, 0, len(c.config.Command)) for _, str := range c.config.Command { command = append(command, str) } return command } // Stdin returns whether STDIN on the container will be kept open func (c *Container) Stdin() bool { return c.config.Stdin } // Labels returns the container's labels func (c *Container) Labels() map[string]string { labels := make(map[string]string) for key, value := range c.config.Labels { labels[key] = value } return labels } // StopSignal is the signal that will be used to stop the container // If it fails to stop the container, SIGKILL will be used after a timeout // If StopSignal is 0, the default signal of SIGTERM will be used func (c *Container) StopSignal() uint { return c.config.StopSignal } // StopTimeout returns the container's stop timeout // If the container's default stop signal fails to kill the container, SIGKILL // will be used after this timeout func (c *Container) StopTimeout() uint { return c.config.StopTimeout } // CreatedTime gets the time when the container was created func (c *Container) CreatedTime() time.Time { return c.config.CreatedTime } // CgroupParent gets the container's CGroup parent func (c *Container) CgroupParent() string { return c.config.CgroupParent } // LogPath returns the path to the container's log file // This file will only be present after Init() is called to create the container // in the runtime func (c *Container) LogPath() string { return c.config.LogPath } // RuntimeName returns the name of the runtime func (c *Container) RuntimeName() string { return c.runtime.ociRuntime.name } // Runtime spec accessors // Unlocked // Hostname gets the container's hostname func (c *Container) Hostname() string { if c.config.Spec.Hostname != "" { return c.config.Spec.Hostname } if len(c.ID()) < 11 { return c.ID() } return c.ID()[:12] } // State Accessors // Require locking // State returns the current state of the container func (c *Container) State() (ContainerStatus, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return ContainerStateUnknown, err } } return c.state.State, nil } // Mounted returns a bool as to if the container's storage // is mounted func (c *Container) Mounted() (bool, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return false, errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.state.Mounted, nil } // Mountpoint returns the path to the container's mounted storage as a string // If the container is not mounted, no error is returned, but the mountpoint // will be "" func (c *Container) Mountpoint() (string, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return "", errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.state.Mountpoint, nil } // StartedTime is the time the container was started func (c *Container) StartedTime() (time.Time, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return time.Time{}, errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.state.StartedTime, nil } // FinishedTime is the time the container was stopped func (c *Container) FinishedTime() (time.Time, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return time.Time{}, errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.state.FinishedTime, nil } // ExitCode returns the exit code of the container as // an int32 func (c *Container) ExitCode() (int32, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return 0, errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.state.ExitCode, nil } // OOMKilled returns whether the container was killed by an OOM condition func (c *Container) OOMKilled() (bool, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return false, errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.state.OOMKilled, nil } // PID returns the PID of the container // If the container is not running, a pid of 0 will be returned. No error will // occur. func (c *Container) PID() (int, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return -1, err } } return c.state.PID, nil } // ExecSessions retrieves active exec sessions running in the container func (c *Container) ExecSessions() ([]string, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return nil, err } } ids := make([]string, 0, len(c.state.ExecSessions)) for id := range c.state.ExecSessions { ids = append(ids, id) } return ids, nil } // ExecSession retrieves detailed information on a single active exec session in // a container func (c *Container) ExecSession(id string) (*ExecSession, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return nil, err } } session, ok := c.state.ExecSessions[id] if !ok { return nil, errors.Wrapf(ErrNoSuchCtr, "no exec session with ID %s found in container %s", id, c.ID()) } returnSession := new(ExecSession) returnSession.ID = session.ID returnSession.Command = session.Command returnSession.PID = session.PID return returnSession, nil } // IPs retrieves a container's IP address(es) // This will only be populated if the container is configured to created a new // network namespace, and that namespace is presently active func (c *Container) IPs() ([]net.IPNet, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return nil, err } } if !c.config.CreateNetNS { return nil, errors.Wrapf(ErrInvalidArg, "container %s network namespace is not managed by libpod") } ips := make([]net.IPNet, 0, len(c.state.IPs)) for _, ip := range c.state.IPs { ips = append(ips, ip.Address) } return ips, nil } // Routes retrieves a container's routes // This will only be populated if the container is configured to created a new // network namespace, and that namespace is presently active func (c *Container) Routes() ([]types.Route, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return nil, err } } if !c.config.CreateNetNS { return nil, errors.Wrapf(ErrInvalidArg, "container %s network namespace is not managed by libpod") } routes := make([]types.Route, 0, len(c.state.Routes)) for _, route := range c.state.Routes { newRoute := types.Route{ Dst: route.Dst, GW: route.GW, } routes = append(routes, newRoute) } return routes, nil } // BindMounts retrieves bind mounts that were created by libpod and will be // added to the container // All these mounts except /dev/shm are ignored if a mount in the given spec has // the same destination // These mounts include /etc/resolv.conf, /etc/hosts, and /etc/hostname // The return is formatted as a map from destination (mountpoint in the // container) to source (path of the file that will be mounted into the // container) // If the container has not been started yet, an empty map will be returned, as // the files in question are only created when the container is started. func (c *Container) BindMounts() (map[string]string, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return nil, err } } newMap := make(map[string]string, len(c.state.BindMounts)) for key, val := range c.state.BindMounts { newMap[key] = val } return newMap, nil } // Misc Accessors // Most will require locking // NamespacePath returns the path of one of the container's namespaces // If the container is not running, an error will be returned func (c *Container) NamespacePath(ns LinuxNS) (string, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return "", errors.Wrapf(err, "error updating container %s state", c.ID()) } } if c.state.State != ContainerStateRunning && c.state.State != ContainerStatePaused { return "", errors.Wrapf(ErrCtrStopped, "cannot get namespace path unless container %s is running", c.ID()) } if ns == InvalidNS { return "", errors.Wrapf(ErrInvalidArg, "invalid namespace requested from container %s", c.ID()) } return fmt.Sprintf("/proc/%d/ns/%s", c.state.PID, ns.String()), nil } // CGroupPath returns a cgroups "path" for a given container. func (c *Container) CGroupPath() (string, error) { switch c.runtime.config.CgroupManager { case CgroupfsCgroupsManager: return filepath.Join(c.config.CgroupParent, fmt.Sprintf("libpod-%s", c.ID()), "ctr"), nil case SystemdCgroupsManager: return filepath.Join(c.config.CgroupParent, createUnitName("libpod", c.ID())), nil default: return "", errors.Wrapf(ErrInvalidArg, "unsupported CGroup manager %s in use", c.runtime.config.CgroupManager) } } // RootFsSize returns the root FS size of the container func (c *Container) RootFsSize() (int64, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return -1, errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.rootFsSize() } // RWSize returns the rw size of the container func (c *Container) RWSize() (int64, error) { if !c.batched { c.lock.Lock() defer c.lock.Unlock() if err := c.syncContainer(); err != nil { return -1, errors.Wrapf(err, "error updating container %s state", c.ID()) } } return c.rwSize() } // IDMappings returns the UID/GID mapping used for the container func (c *Container) IDMappings() (storage.IDMappingOptions, error) { return c.config.IDMappings, nil } // RootUID returns the root user mapping from container func (c *Container) RootUID() int { for _, uidmap := range c.config.IDMappings.UIDMap { if uidmap.ContainerID == 0 { return uidmap.HostID } } return 0 } // RootGID returns the root user mapping from container func (c *Container) RootGID() int { for _, gidmap := range c.config.IDMappings.GIDMap { if gidmap.ContainerID == 0 { return gidmap.HostID } } return 0 }