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moby--moby/daemon/start.go

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package daemon
import (
"context"
"runtime"
"time"
"github.com/docker/docker/api/types"
containertypes "github.com/docker/docker/api/types/container"
"github.com/docker/docker/container"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
// ContainerStart starts a container.
func (daemon *Daemon) ContainerStart(name string, hostConfig *containertypes.HostConfig, checkpoint string, checkpointDir string) error {
if checkpoint != "" && !daemon.HasExperimental() {
return validationError{errors.New("checkpoint is only supported in experimental mode")}
}
container, err := daemon.GetContainer(name)
if err != nil {
return err
}
validateState := func() error {
container.Lock()
defer container.Unlock()
if container.Paused {
return stateConflictError{errors.New("cannot start a paused container, try unpause instead")}
}
if container.Running {
return containerNotModifiedError{running: true}
}
if container.RemovalInProgress || container.Dead {
return stateConflictError{errors.New("container is marked for removal and cannot be started")}
}
return nil
}
if err := validateState(); err != nil {
return err
}
// Windows does not have the backwards compatibility issue here.
if runtime.GOOS != "windows" {
// This is kept for backward compatibility - hostconfig should be passed when
// creating a container, not during start.
if hostConfig != nil {
logrus.Warn("DEPRECATED: Setting host configuration options when the container starts is deprecated and has been removed in Docker 1.12")
oldNetworkMode := container.HostConfig.NetworkMode
if err := daemon.setSecurityOptions(container, hostConfig); err != nil {
return validationError{err}
}
if err := daemon.mergeAndVerifyLogConfig(&hostConfig.LogConfig); err != nil {
return validationError{err}
}
if err := daemon.setHostConfig(container, hostConfig); err != nil {
return validationError{err}
}
newNetworkMode := container.HostConfig.NetworkMode
if string(oldNetworkMode) != string(newNetworkMode) {
// if user has change the network mode on starting, clean up the
// old networks. It is a deprecated feature and has been removed in Docker 1.12
container.NetworkSettings.Networks = nil
if err := container.CheckpointTo(daemon.containersReplica); err != nil {
return systemError{err}
}
}
container.InitDNSHostConfig()
}
} else {
if hostConfig != nil {
return validationError{errors.New("Supplying a hostconfig on start is not supported. It should be supplied on create")}
}
}
// check if hostConfig is in line with the current system settings.
// It may happen cgroups are umounted or the like.
if _, err = daemon.verifyContainerSettings(container.OS, container.HostConfig, nil, false); err != nil {
return validationError{err}
}
// Adapt for old containers in case we have updates in this function and
// old containers never have chance to call the new function in create stage.
if hostConfig != nil {
if err := daemon.adaptContainerSettings(container.HostConfig, false); err != nil {
return validationError{err}
}
}
if err := daemon.containerStart(container, checkpoint, checkpointDir, true); err != nil {
return err
}
return nil
}
// containerStart prepares the container to run by setting up everything the
// container needs, such as storage and networking, as well as links
// between containers. The container is left waiting for a signal to
// begin running.
func (daemon *Daemon) containerStart(container *container.Container, checkpoint string, checkpointDir string, resetRestartManager bool) (err error) {
start := time.Now()
container.Lock()
defer container.Unlock()
if resetRestartManager && container.Running { // skip this check if already in restarting step and resetRestartManager==false
return nil
}
if container.RemovalInProgress || container.Dead {
return stateConflictError{errors.New("container is marked for removal and cannot be started")}
}
if checkpointDir != "" {
// TODO(mlaventure): how would we support that?
return notAllowedError{errors.New("custom checkpointdir is not supported")}
}
// if we encounter an error during start we need to ensure that any other
// setup has been cleaned up properly
defer func() {
if err != nil {
container.SetError(err)
// if no one else has set it, make sure we don't leave it at zero
if container.ExitCode() == 0 {
container.SetExitCode(128)
}
if err := container.CheckpointTo(daemon.containersReplica); err != nil {
logrus.Errorf("%s: failed saving state on start failure: %v", container.ID, err)
}
container.Reset(false)
daemon.Cleanup(container)
// if containers AutoRemove flag is set, remove it after clean up
if container.HostConfig.AutoRemove {
container.Unlock()
if err := daemon.ContainerRm(container.ID, &types.ContainerRmConfig{ForceRemove: true, RemoveVolume: true}); err != nil {
logrus.Errorf("can't remove container %s: %v", container.ID, err)
}
container.Lock()
}
}
}()
if err := daemon.conditionalMountOnStart(container); err != nil {
return err
}
if err := daemon.initializeNetworking(container); err != nil {
return err
}
spec, err := daemon.createSpec(container)
if err != nil {
return systemError{err}
}
if resetRestartManager {
container.ResetRestartManager(true)
}
if daemon.saveApparmorConfig(container); err != nil {
return err
}
if checkpoint != "" {
checkpointDir, err = getCheckpointDir(checkpointDir, checkpoint, container.Name, container.ID, container.CheckpointDir(), false)
if err != nil {
return err
}
}
createOptions, err := daemon.getLibcontainerdCreateOptions(container)
if err != nil {
return err
}
err = daemon.containerd.Create(context.Background(), container.ID, spec, createOptions)
if err != nil {
return translateContainerdStartErr(container.Path, container.SetExitCode, err)
}
// TODO(mlaventure): we need to specify checkpoint options here
pid, err := daemon.containerd.Start(context.Background(), container.ID, checkpointDir,
container.StreamConfig.Stdin() != nil || container.Config.Tty,
container.InitializeStdio)
if err != nil {
if err := daemon.containerd.Delete(context.Background(), container.ID); err != nil {
logrus.WithError(err).WithField("container", container.ID).
Error("failed to delete failed start container")
}
return translateContainerdStartErr(container.Path, container.SetExitCode, err)
}
container.SetRunning(pid, true)
container.HasBeenManuallyStopped = false
container.HasBeenStartedBefore = true
daemon.setStateCounter(container)
daemon.initHealthMonitor(container)
if err := container.CheckpointTo(daemon.containersReplica); err != nil {
logrus.WithError(err).WithField("container", container.ID).
Errorf("failed to store container")
}
daemon.LogContainerEvent(container, "start")
containerActions.WithValues("start").UpdateSince(start)
return nil
}
// Cleanup releases any network resources allocated to the container along with any rules
// around how containers are linked together. It also unmounts the container's root filesystem.
func (daemon *Daemon) Cleanup(container *container.Container) {
daemon.releaseNetwork(container)
Implement none, private, and shareable ipc modes Since the commit d88fe447df0e8 ("Add support for sharing /dev/shm/ and /dev/mqueue between containers") container's /dev/shm is mounted on the host first, then bind-mounted inside the container. This is done that way in order to be able to share this container's IPC namespace (and the /dev/shm mount point) with another container. Unfortunately, this functionality breaks container checkpoint/restore (even if IPC is not shared). Since /dev/shm is an external mount, its contents is not saved by `criu checkpoint`, and so upon restore any application that tries to access data under /dev/shm is severily disappointed (which usually results in a fatal crash). This commit solves the issue by introducing new IPC modes for containers (in addition to 'host' and 'container:ID'). The new modes are: - 'shareable': enables sharing this container's IPC with others (this used to be the implicit default); - 'private': disables sharing this container's IPC. In 'private' mode, container's /dev/shm is truly mounted inside the container, without any bind-mounting from the host, which solves the issue. While at it, let's also implement 'none' mode. The motivation, as eloquently put by Justin Cormack, is: > I wondered a while back about having a none shm mode, as currently it is > not possible to have a totally unwriteable container as there is always > a /dev/shm writeable mount. It is a bit of a niche case (and clearly > should never be allowed to be daemon default) but it would be trivial to > add now so maybe we should... ...so here's yet yet another mode: - 'none': no /dev/shm mount inside the container (though it still has its own private IPC namespace). Now, to ultimately solve the abovementioned checkpoint/restore issue, we'd need to make 'private' the default mode, but unfortunately it breaks the backward compatibility. So, let's make the default container IPC mode per-daemon configurable (with the built-in default set to 'shareable' for now). The default can be changed either via a daemon CLI option (--default-shm-mode) or a daemon.json configuration file parameter of the same name. Note one can only set either 'shareable' or 'private' IPC modes as a daemon default (i.e. in this context 'host', 'container', or 'none' do not make much sense). Some other changes this patch introduces are: 1. A mount for /dev/shm is added to default OCI Linux spec. 2. IpcMode.Valid() is simplified to remove duplicated code that parsed 'container:ID' form. Note the old version used to check that ID does not contain a semicolon -- this is no longer the case (tests are modified accordingly). The motivation is we should either do a proper check for container ID validity, or don't check it at all (since it is checked in other places anyway). I chose the latter. 3. IpcMode.Container() is modified to not return container ID if the mode value does not start with "container:", unifying the check to be the same as in IpcMode.IsContainer(). 3. IPC mode unit tests (runconfig/hostconfig_test.go) are modified to add checks for newly added values. [v2: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-51345997] [v3: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-53902833] [v4: addressed the case of upgrading from older daemon, in this case container.HostConfig.IpcMode is unset and this is valid] [v5: document old and new IpcMode values in api/swagger.yaml] [v6: add the 'none' mode, changelog entry to docs/api/version-history.md] Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2017-06-27 17:58:50 -04:00
if err := container.UnmountIpcMount(detachMounted); err != nil {
logrus.Warnf("%s cleanup: failed to unmount IPC: %s", container.ID, err)
}
if err := daemon.conditionalUnmountOnCleanup(container); err != nil {
// FIXME: remove once reference counting for graphdrivers has been refactored
// Ensure that all the mounts are gone
if mountid, err := daemon.stores[container.OS].layerStore.GetMountID(container.ID); err == nil {
daemon.cleanupMountsByID(mountid)
}
}
if err := container.UnmountSecrets(); err != nil {
logrus.Warnf("%s cleanup: failed to unmount secrets: %s", container.ID, err)
}
for _, eConfig := range container.ExecCommands.Commands() {
daemon.unregisterExecCommand(container, eConfig)
}
if container.BaseFS != nil && container.BaseFS.Path() != "" {
2016-10-03 13:53:06 -04:00
if err := container.UnmountVolumes(daemon.LogVolumeEvent); err != nil {
logrus.Warnf("%s cleanup: Failed to umount volumes: %v", container.ID, err)
}
}
container.CancelAttachContext()
if err := daemon.containerd.Delete(context.Background(), container.ID); err != nil {
logrus.Errorf("%s cleanup: failed to delete container from containerd: %v", container.ID, err)
}
}