func createContainer(
lxcContainer golxc.Container,
directory string,
networkConfig *container.NetworkConfig,
extraCreateArgs, templateParams []string,
caCert []byte,
) error {
// Generate initial lxc.conf with networking settings.
netConfig := generateNetworkConfig(networkConfig)
configPath := filepath.Join(directory, "lxc.conf")
if err := ioutil.WriteFile(configPath, []byte(netConfig), 0644); err != nil {
return errors.Annotatef(err, "failed to write container config %q", configPath)
}
logger.Tracef("wrote initial config %q for container %q", configPath, lxcContainer.Name())
var err error
var execEnv []string = nil
var closer func()
if caCert != nil {
execEnv, closer, err = wgetEnvironment(caCert)
if err != nil {
return errors.Annotatef(err, "failed to get environment for wget execution")
}
defer closer()
}
// Create the container.
logger.Debugf("creating lxc container %q", lxcContainer.Name())
logger.Debugf("lxc-create template params: %v", templateParams)
if err := lxcContainer.Create(configPath, defaultTemplate, extraCreateArgs, templateParams, execEnv); err != nil {
return errors.Annotatef(err, "lxc container creation failed")
}
return nil
}
func contains(lcs []golxc.Container, lc golxc.Container) bool {
for _, clc := range lcs {
if clc.Name() == lc.Name() {
return true
}
}
return false
}
// CreateContainer creates or clones an LXC container.
func (manager *containerManager) CreateContainer(
instanceConfig *instancecfg.InstanceConfig,
series string,
networkConfig *container.NetworkConfig,
storageConfig *container.StorageConfig,
) (inst instance.Instance, _ *instance.HardwareCharacteristics, err error) {
// Check our preconditions
if manager == nil {
panic("manager is nil")
} else if series == "" {
panic("series not set")
} else if networkConfig == nil {
panic("networkConfig is nil")
} else if storageConfig == nil {
panic("storageConfig is nil")
}
// Log how long the start took
defer func(start time.Time) {
if err == nil {
logger.Tracef("container %q started: %v", inst.Id(), time.Now().Sub(start))
}
}(time.Now())
name := names.NewMachineTag(instanceConfig.MachineId).String()
if manager.name != "" {
name = fmt.Sprintf("%s-%s", manager.name, name)
}
// Create the cloud-init.
directory, err := container.NewDirectory(name)
if err != nil {
return nil, nil, errors.Annotate(err, "failed to create a directory for the container")
}
logger.Tracef("write cloud-init")
userDataFilename, err := containerinit.WriteUserData(instanceConfig, networkConfig, directory)
if err != nil {
return nil, nil, errors.Annotate(err, "failed to write user data")
}
var lxcContainer golxc.Container
if manager.createWithClone {
templateContainer, err := EnsureCloneTemplate(
manager.backingFilesystem,
series,
networkConfig,
instanceConfig.AuthorizedKeys,
instanceConfig.AptProxySettings,
instanceConfig.AptMirror,
instanceConfig.EnableOSRefreshUpdate,
instanceConfig.EnableOSUpgrade,
manager.imageURLGetter,
manager.useAUFS,
)
if err != nil {
return nil, nil, errors.Annotate(err, "failed to retrieve the template to clone")
}
templateParams := []string{
"--debug", // Debug errors in the cloud image
"--userdata", userDataFilename, // Our groovey cloud-init
"--hostid", name, // Use the container name as the hostid
}
var extraCloneArgs []string
if manager.backingFilesystem == Btrfs || manager.useAUFS {
extraCloneArgs = append(extraCloneArgs, "--snapshot")
}
if manager.backingFilesystem != Btrfs && manager.useAUFS {
extraCloneArgs = append(extraCloneArgs, "--backingstore", "aufs")
}
lock, err := AcquireTemplateLock(templateContainer.Name(), "clone")
if err != nil {
return nil, nil, errors.Annotate(err, "failed to acquire lock on template")
}
defer lock.Unlock()
// Ensure the run-time effective config of the template
// container has correctly ordered network settings, otherwise
// Clone() below will fail. This is needed in case we haven't
// created a new template now but are reusing an existing one.
// See LP bug #1414016.
configPath := containerConfigFilename(templateContainer.Name())
if _, err := reorderNetworkConfig(configPath); err != nil {
return nil, nil, errors.Annotate(err, "failed to reorder network settings")
}
lxcContainer, err = templateContainer.Clone(name, extraCloneArgs, templateParams)
if err != nil {
return nil, nil, errors.Annotate(err, "lxc container cloning failed")
}
} else {
// Note here that the lxcObjectFacotry only returns a valid container
// object, and doesn't actually construct the underlying lxc container on
// disk.
lxcContainer = LxcObjectFactory.New(name)
templateParams := []string{
"--debug", // Debug errors in the cloud image
"--userdata", userDataFilename, // Our groovey cloud-init
"--hostid", name, // Use the container name as the hostid
"-r", series,
}
var caCert []byte
if manager.imageURLGetter != nil {
arch := arch.HostArch()
imageURL, err := manager.imageURLGetter.ImageURL(instance.LXC, series, arch)
if err != nil {
return nil, nil, errors.Annotatef(err, "cannot determine cached image URL")
}
templateParams = append(templateParams, "-T", imageURL)
caCert = manager.imageURLGetter.CACert()
}
err = createContainer(
lxcContainer,
directory,
networkConfig,
nil,
templateParams,
caCert,
)
if err != nil {
return nil, nil, errors.Trace(err)
}
}
if err := autostartContainer(name); err != nil {
return nil, nil, errors.Annotate(err, "failed to configure the container for autostart")
}
if err := mountHostLogDir(name, manager.logdir); err != nil {
return nil, nil, errors.Annotate(err, "failed to mount the directory to log to")
}
if storageConfig.AllowMount {
// Add config to allow loop devices to be mounted inside the container.
if err := allowLoopbackBlockDevices(name); err != nil {
return nil, nil, errors.Annotate(err, "failed to configure the container for loopback devices")
}
}
// Update the network settings inside the run-time config of the
// container (e.g. /var/lib/lxc/<name>/config) before starting it.
netConfig := generateNetworkConfig(networkConfig)
if err := updateContainerConfig(name, netConfig); err != nil {
return nil, nil, errors.Annotate(err, "failed to update network config")
}
configPath := containerConfigFilename(name)
logger.Tracef("updated network config in %q for container %q", configPath, name)
// Ensure the run-time config of the new container has correctly
// ordered network settings, otherwise Start() below will fail. We
// need this now because after lxc-create or lxc-clone the initial
// lxc.conf generated inside createContainer gets merged with
// other settings (e.g. system-wide overrides, changes made by
// hooks, etc.) and the result can still be incorrectly ordered.
// See LP bug #1414016.
if _, err := reorderNetworkConfig(configPath); err != nil {
return nil, nil, errors.Annotate(err, "failed to reorder network settings")
}
// To speed-up the initial container startup we pre-render the
// /etc/network/interfaces directly inside the rootfs. This won't
// work if we use AUFS snapshots, so it's disabled if useAUFS is
// true (for now).
if networkConfig != nil && len(networkConfig.Interfaces) > 0 {
interfacesFile := filepath.Join(LxcContainerDir, name, "rootfs", etcNetworkInterfaces)
if manager.useAUFS {
logger.Tracef("not pre-rendering %q when using AUFS-backed rootfs", interfacesFile)
} else {
data, err := containerinit.GenerateNetworkConfig(networkConfig)
if err != nil {
return nil, nil, errors.Annotatef(err, "failed to generate %q", interfacesFile)
}
if err := utils.AtomicWriteFile(interfacesFile, []byte(data), 0644); err != nil {
return nil, nil, errors.Annotatef(err, "cannot write generated %q", interfacesFile)
}
logger.Tracef("pre-rendered network config in %q", interfacesFile)
}
}
// Start the lxc container with the appropriate settings for
// grabbing the console output and a log file.
consoleFile := filepath.Join(directory, "console.log")
lxcContainer.SetLogFile(filepath.Join(directory, "container.log"), golxc.LogDebug)
logger.Tracef("start the container")
// We explicitly don't pass through the config file to the container.Start
// method as we have passed it through at container creation time. This
// is necessary to get the appropriate rootfs reference without explicitly
// setting it ourselves.
if err = lxcContainer.Start("", consoleFile); err != nil {
logger.Warningf("container failed to start %v", err)
// if the container fails to start we should try to destroy it
// check if the container has been constructed
if lxcContainer.IsConstructed() {
// if so, then we need to destroy the leftover container
if derr := lxcContainer.Destroy(); derr != nil {
// if an error is reported there is probably a leftover
// container that the user should clean up manually
logger.Errorf("container failed to start and failed to destroy: %v", derr)
return nil, nil, errors.Annotate(err, "container failed to start and failed to destroy: manual cleanup of containers needed")
}
logger.Warningf("container failed to start and was destroyed - safe to retry")
return nil, nil, errors.Wrap(err, instance.NewRetryableCreationError("container failed to start and was destroyed: "+lxcContainer.Name()))
}
logger.Warningf("container failed to start: %v", err)
return nil, nil, errors.Annotate(err, "container failed to start")
}
hardware := &instance.HardwareCharacteristics{
Arch: &version.Current.Arch,
}
return &lxcInstance{lxcContainer, name}, hardware, nil
}