// Make sure a template exists that we can clone from.
func EnsureCloneTemplate(
backingFilesystem string,
series string,
network *container.NetworkConfig,
authorizedKeys string,
aptProxy proxy.Settings,
) (golxc.Container, error) {
name := fmt.Sprintf("juju-%s-template", series)
containerDirectory, err := container.NewDirectory(name)
if err != nil {
return nil, err
}
lock, err := AcquireTemplateLock(name, "ensure clone exists")
if err != nil {
return nil, err
}
defer lock.Unlock()
lxcContainer := LxcObjectFactory.New(name)
// Early exit if the container has been constructed before.
if lxcContainer.IsConstructed() {
logger.Infof("template exists, continuing")
return lxcContainer, nil
}
logger.Infof("template does not exist, creating")
userData, err := templateUserData(series, authorizedKeys, aptProxy)
if err != nil {
logger.Tracef("failed to create template user data for template: %v", err)
return nil, err
}
userDataFilename, err := container.WriteCloudInitFile(containerDirectory, userData)
if err != nil {
return nil, err
}
configFile, err := writeLxcConfig(network, containerDirectory)
if err != nil {
logger.Errorf("failed to write config file: %v", err)
return nil, err
}
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 extraCreateArgs []string
if backingFilesystem == Btrfs {
extraCreateArgs = append(extraCreateArgs, "-B", Btrfs)
}
// Create the container.
logger.Tracef("create the container")
if err := lxcContainer.Create(configFile, defaultTemplate, extraCreateArgs, templateParams); err != nil {
logger.Errorf("lxc container creation failed: %v", err)
return nil, err
}
// Make sure that the mount dir has been created.
logger.Tracef("make the mount dir for the shared logs")
if err := os.MkdirAll(internalLogDir(name), 0755); err != nil {
logger.Tracef("failed to create internal /var/log/juju mount dir: %v", err)
return nil, err
}
// Start the lxc container with the appropriate settings for grabbing the
// console output and a log file.
consoleFile := filepath.Join(containerDirectory, "console.log")
lxcContainer.SetLogFile(filepath.Join(containerDirectory, "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.Errorf("container failed to start: %v", err)
return nil, err
}
logger.Infof("template container started, now wait for it to stop")
// Perhaps we should wait for it to finish, and the question becomes "how
// long do we wait for it to complete?"
console, err := os.Open(consoleFile)
if err != nil {
// can't listen
return nil, err
}
tailWriter := &logTail{tick: time.Now()}
consoleTailer := tailer.NewTailer(console, tailWriter, nil)
defer consoleTailer.Stop()
// We should wait maybe 1 minute between output?
// if no output check to see if stopped
// If we have no output and still running, something has probably gone wrong
for lxcContainer.IsRunning() {
if tailWriter.lastTick().Before(time.Now().Add(-TemplateStopTimeout)) {
logger.Infof("not heard anything from the template log for five minutes")
return nil, fmt.Errorf("template container %q did not stop", name)
}
time.Sleep(time.Second)
}
return lxcContainer, nil
}
// start the tailer listening to the logFile, and sending the matching
// lines to the writer.
func (stream *logStream) start(logFile io.ReadSeeker, writer io.Writer) {
stream.logTailer = tailer.NewTailer(logFile, writer, stream.countedFilterLine)
}