common

Documentation

Overview

Package common and the file kvm_mount.go provide functions for creating mount units for managing inner(kind=empty) and external(kind=host) volumes. note: used only for kvm flavor (lkvm based)

Idea. For example when we have two volumes: 1) --volume=hostdata,kind=host,source=/host/some_data_to_share 2) --volume=temporary,kind=empty then in stage1/rootfs rkt creates two folders (in rootfs of guest)

1. /mnt/hostdata - which is mounted through 9p host thanks to lkvm --9p=/host/some_data_to_share,hostdata flag shared to quest
2. /mnt/temporary - is created as empty directory in guest

both of them are then bind mounted to /opt/stage2/<application/<mountPoint.path> for every application, that has mountPoints specified in ACI json

• host mounting is realized by podToSystemdHostMountUnits (for whole pod), which creates mount.units (9p) required and ordered before all applications service units
• bind mounting is realized by appToSystemdMountUnits (for each app), which creates mount.units (bind) required and ordered before particular application

note: systemd mount units require /usr/bin/mount

Index

• Constants
• func AppToSystemdMountUnits(root string, appName types.ACName, volumes []types.Volume, ...) error
• func EnvFilePath(root string, appName types.ACName) string
• func GetAppHashes(p *stage1commontypes.Pod) []types.Hash
• func GetFlavor(p *stage1commontypes.Pod) (flavor string, systemdVersion int, err error)
• func GetMachineID(p *stage1commontypes.Pod) string
• func InitDebug(debug bool)
• func InstantiatedPrepareAppUnitName(appName types.ACName) string
• func IsMountReadOnly(vol types.Volume, mountPoints []types.MountPoint) bool
• func PodToNspawnArgs(p *stage1commontypes.Pod) ([]string, error)
• func PodToSystemd(p *stage1commontypes.Pod, interactive bool, flavor string, privateUsers string) error
• func PodToSystemdHostMountUnits(root string, volumes []types.Volume, appNames []types.ACName, unitsDir string) error
• func PrepareMountpoints(volPath string, targetPath string, vol *types.Volume, dockerImplicit bool) error
• func RelEnvFilePath(appName types.ACName) string
• func ServiceUnitName(appName types.ACName) string
• func ServiceUnitPath(root string, appName types.ACName) string
• func ServiceWantPath(root string, appName types.ACName) string
• func SetJournalPermissions(p *stage1commontypes.Pod) error
• func SocketUnitName(appName types.ACName) string
• func SocketUnitPath(root string, appName types.ACName) string
• func SocketWantPath(root string, appName types.ACName) string
• func VolumesToKvmDiskArgs(volumes []types.Volume) []string
• func WriteDefaultTarget(p *stage1commontypes.Pod) error
• func WritePrepareAppTemplate(p *stage1commontypes.Pod) error

Constants

const (
	// FlavorFile names the file storing the pod's flavor
	FlavorFile = "flavor"
)

const (
	// UnitsDir is the default path to systemd systemd unit directory
	UnitsDir = "/usr/lib/systemd/system"
)

Functions

func AppToSystemdMountUnits

func AppToSystemdMountUnits(root string, appName types.ACName, volumes []types.Volume, ra *schema.RuntimeApp, unitsDir string) error

AppToSystemdMountUnits prepare bind mount unit for empty or host kind mounting between stage1 rootfs and chrooted filesystem for application

func EnvFilePath

func EnvFilePath(root string, appName types.ACName) string

EnvFilePath returns the path to the environment file for the given app name.

func GetAppHashes

func GetAppHashes(p *stage1commontypes.Pod) []types.Hash

GetAppHashes returns a list of hashes of the apps in this pod

func GetFlavor

func GetFlavor(p *stage1commontypes.Pod) (flavor string, systemdVersion int, err error)

GetFlavor populates a flavor string based on the flavor itself and respectively the systemd version If the systemd version couldn't be guessed, it will be set to 0.

func GetMachineID

func GetMachineID(p *stage1commontypes.Pod) string

GetMachineID returns the machine id string of the pod to be passed to systemd-nspawn

func InitDebug

func InitDebug(debug bool)

func InstantiatedPrepareAppUnitName

func InstantiatedPrepareAppUnitName(appName types.ACName) string

InstantiatedPrepareAppUnitName returns the systemd service unit name for prepare-app instantiated for the given root.

func IsMountReadOnly

func IsMountReadOnly(vol types.Volume, mountPoints []types.MountPoint) bool

IsMountReadOnly returns if a mount should be readOnly. If the readOnly flag in the pod manifest is not nil, it overrides the readOnly flag in the image manifest.

func PodToNspawnArgs

func PodToNspawnArgs(p *stage1commontypes.Pod) ([]string, error)

PodToNspawnArgs renders a prepared Pod as a systemd-nspawn argument list ready to be executed

func PodToSystemd

func PodToSystemd(p *stage1commontypes.Pod, interactive bool, flavor string, privateUsers string) error

PodToSystemd creates the appropriate systemd service unit files for all the constituent apps of the Pod

func PodToSystemdHostMountUnits

func PodToSystemdHostMountUnits(root string, volumes []types.Volume, appNames []types.ACName, unitsDir string) error

PodToSystemdHostMountUnits create host shared remote file system mounts (using e.g. 9p) according to https://www.kernel.org/doc/Documentation/filesystems/9p.txt. Additionally it creates required directories in stage1MntDir and then prepares bind mount unit for each app. "root" parameter is stage1 root filesystem path. appNames are used to create before/required dependency between mount unit and app service units.

func PrepareMountpoints

func PrepareMountpoints(volPath string, targetPath string, vol *types.Volume, dockerImplicit bool) error

PrepareMountpoints creates and sets permissions for empty volumes. If the mountpoint comes from a Docker image and it is an implicit empty volume, we copy files from the image to the volume, see https://docs.docker.com/engine/userguide/containers/dockervolumes/#data-volumes

func RelEnvFilePath

func RelEnvFilePath(appName types.ACName) string

RelEnvFilePath returns the path to the environment file for the given app name relative to the pod's root.

func ServiceUnitName

func ServiceUnitName(appName types.ACName) string

ServiceUnitName returns a systemd service unit name for the given app name.

func ServiceUnitPath

func ServiceUnitPath(root string, appName types.ACName) string

ServiceUnitPath returns the path to the systemd service file for the given app name.

func ServiceWantPath

func ServiceWantPath(root string, appName types.ACName) string

ServiceWantPath returns the systemd default.target want symlink path for the given app name.

func SetJournalPermissions

func SetJournalPermissions(p *stage1commontypes.Pod) error

SetJournalPermissions sets ACLs and permissions so the rkt group can access the pod's logs

func SocketUnitName

func SocketUnitName(appName types.ACName) string

SocketUnitName returns a systemd socket unit name for the given app name.

func SocketUnitPath

func SocketUnitPath(root string, appName types.ACName) string

SocketUnitPath returns the path to the systemd socket file for the given app name.

func SocketWantPath

func SocketWantPath(root string, appName types.ACName) string

SocketWantPath returns the systemd sockets.target.wants symlink path for the given app name.

func VolumesToKvmDiskArgs

func VolumesToKvmDiskArgs(volumes []types.Volume) []string

VolumesToKvmDiskArgs prepares argument list to be passed to lkvm to configure shared volumes (only for "host" kind). Example return is ["--9p,src/folder,9ptag"].

func WriteDefaultTarget

func WriteDefaultTarget(p *stage1commontypes.Pod) error

WriteDefaultTarget writes the default.target unit file which is responsible for bringing up the applications

func WritePrepareAppTemplate

func WritePrepareAppTemplate(p *stage1commontypes.Pod) error

WritePrepareAppTemplate writes service unit files for preparing the pod's applications