Example #1
0
// 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) (err error) {
	container.Lock()
	defer container.Unlock()

	if container.Running {
		return nil
	}

	if container.RemovalInProgress || container.Dead {
		return fmt.Errorf("Container is marked for removal and cannot be started.")
	}

	// 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.ExitCode = 128
			}
			container.ToDisk()
			daemon.Cleanup(container)
		}
	}()

	if err := daemon.conditionalMountOnStart(container); err != nil {
		return err
	}

	// Make sure NetworkMode has an acceptable value. We do this to ensure
	// backwards API compatibility.
	container.HostConfig = runconfig.SetDefaultNetModeIfBlank(container.HostConfig)

	if err := daemon.initializeNetworking(container); err != nil {
		return err
	}

	spec, err := daemon.createSpec(container)
	if err != nil {
		return err
	}

	if err := daemon.containerd.Create(container.ID, *spec, libcontainerd.WithRestartManager(container.RestartManager(true))); err != nil {
		errDesc := grpc.ErrorDesc(err)
		logrus.Errorf("Create container failed with error: %s", errDesc)
		// if we receive an internal error from the initial start of a container then lets
		// return it instead of entering the restart loop
		// set to 127 for container cmd not found/does not exist)
		if strings.Contains(errDesc, "executable file not found") ||
			strings.Contains(errDesc, "no such file or directory") ||
			strings.Contains(errDesc, "system cannot find the file specified") {
			container.ExitCode = 127
		}
		// set to 126 for container cmd can't be invoked errors
		if strings.Contains(errDesc, syscall.EACCES.Error()) {
			container.ExitCode = 126
		}

		container.Reset(false)

		return fmt.Errorf("%s", errDesc)
	}

	return nil
}
Example #2
0
// 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, resetRestartManager bool) (err error) {
	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 fmt.Errorf("Container is marked for removal and cannot be started.")
	}

	// 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)
			}
			container.ToDisk()
			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
	}

	// Make sure NetworkMode has an acceptable value. We do this to ensure
	// backwards API compatibility.
	container.HostConfig = runconfig.SetDefaultNetModeIfBlank(container.HostConfig)

	if err := daemon.initializeNetworking(container); err != nil {
		return err
	}

	spec, err := daemon.createSpec(container)
	if err != nil {
		return err
	}

	createOptions, err := daemon.getLibcontainerdCreateOptions(container)
	if err != nil {
		return err
	}

	if resetRestartManager {
		container.ResetRestartManager(true)
	}

	if err := daemon.containerd.Create(container.ID, checkpoint, container.CheckpointDir(), *spec, container.InitializeStdio, createOptions...); err != nil {
		errDesc := grpc.ErrorDesc(err)
		logrus.Errorf("Create container failed with error: %s", errDesc)
		// if we receive an internal error from the initial start of a container then lets
		// return it instead of entering the restart loop
		// set to 127 for container cmd not found/does not exist)
		if strings.Contains(errDesc, container.Path) &&
			(strings.Contains(errDesc, "executable file not found") ||
				strings.Contains(errDesc, "no such file or directory") ||
				strings.Contains(errDesc, "system cannot find the file specified")) {
			container.SetExitCode(127)
		}
		// set to 126 for container cmd can't be invoked errors
		if strings.Contains(errDesc, syscall.EACCES.Error()) {
			container.SetExitCode(126)
		}

		// attempted to mount a file onto a directory, or a directory onto a file, maybe from user specified bind mounts
		if strings.Contains(errDesc, syscall.ENOTDIR.Error()) {
			errDesc += ": Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type"
			container.SetExitCode(127)
		}

		container.Reset(false)

		return fmt.Errorf("%s", errDesc)
	}

	return nil
}
Example #3
0
// 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.
//容器启动的核心方法。
func (daemon *Daemon) containerStart(container *container.Container) (err error) {

	//这里的锁是干什么的?
	container.Lock()
	defer container.Unlock()

	if container.Running {
		return nil
	}

	if container.RemovalInProgress || container.Dead {
		return fmt.Errorf("Container is marked for removal and cannot be started.")
	}

	// 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.ExitCode = 128
			}
			container.ToDisk()
			daemon.Cleanup(container)

			attributes := map[string]string{
				"exitCode": fmt.Sprintf("%d", container.ExitCode),
			}
			daemon.LogContainerEventWithAttributes(container, "die", attributes)
		}
	}()

	//挂载容器的文件系统。会调用daemon/daemon.go中的Mount()方法。
	//不过那个方法比较奇怪,感觉正常情况下并不会做什么事情。

	if err := daemon.conditionalMountOnStart(container); err != nil {
		return err
	}

	// Make sure NetworkMode has an acceptable value. We do this to ensure
	// backwards API compatibility.
	//设置默认的网络模式。
	container.HostConfig = runconfig.SetDefaultNetModeIfBlank(container.HostConfig)

	/*
		initializeNetworking() 对网络进行初始化,docker网络模式有三种,分别是 bridge模式
		(每个容器用户单独的网络栈),host模式(与宿主机共用一个网络栈),contaier模式
		(与其他容器共用一个网络栈,猜测kubernate中的pod所用的模式);
		根据config和hostConfig中的参数来确定容器的网络模式,然后调动libnetwork包来建立网络
	*/
	if err := daemon.initializeNetworking(container); err != nil {
		return err
	}

	//创建容器关于namespace和cgroup等的运行环境。在daemon/oci_linux.go中。
	//Spec中包括了容器的最基本的信息。
	spec, err := daemon.createSpec(container)
	if err != nil {
		return err
	}

	//运行容器,详细请见libcontainerd/client_linux.go中Create()方法。
	if err := daemon.containerd.Create(container.ID, *spec, libcontainerd.WithRestartManager(container.RestartManager(true))); err != nil {
		// if we receive an internal error from the initial start of a container then lets
		// return it instead of entering the restart loop
		// set to 127 for container cmd not found/does not exist)
		if strings.Contains(err.Error(), "executable file not found") ||
			strings.Contains(err.Error(), "no such file or directory") ||
			strings.Contains(err.Error(), "system cannot find the file specified") {
			container.ExitCode = 127
			err = fmt.Errorf("Container command '%s' not found or does not exist.", container.Path)
		}
		// set to 126 for container cmd can't be invoked errors
		if strings.Contains(err.Error(), syscall.EACCES.Error()) {
			container.ExitCode = 126
			err = fmt.Errorf("Container command '%s' could not be invoked.", container.Path)
		}

		container.Reset(false)

		// start event is logged even on error
		daemon.LogContainerEvent(container, "start")
		return err
	}

	return nil
}