[CRIU] [PATCH v5] Add docker phaul driver

Pavel Emelyanov xemul at parallels.com
Mon Oct 26 12:47:04 PDT 2015


On 10/26/2015 10:44 PM, Hui Kang wrote:
> On Mon, Oct 26, 2015 at 3:41 PM, Hui Kang <hkang.sunysb at gmail.com> wrote:
>> On Mon, Oct 26, 2015 at 2:26 PM, Pavel Emelyanov <xemul at parallels.com> wrote:
>>> On 10/26/2015 08:59 PM, Hui Kang wrote:
>>>> Hi, Pavel
>>>> Thanks for your comment. Please see my reply inline.
>>>>
>>>> On Mon, Oct 26, 2015 at 5:06 AM, Pavel Emelyanov <xemul at parallels.com> wrote:
>>>>> Please, find my comment inline.
>>>>>
>>>>>> diff --git a/p.haul b/p.haul
>>>>>> index 11460b4..478e1c7 100755
>>>>>> --- a/p.haul
>>>>>> +++ b/p.haul
>>>>>> @@ -25,7 +25,7 @@ import phaul.htype
>>>>>>
>>>>>>  parser = argparse.ArgumentParser("Process HAULer")
>>>>>>  parser.add_argument("type", choices=phaul.htype.get_haul_names(),
>>>>>> -     help="Type of hat to haul, e.g. vz or lxc")
>>>>>> +     help="Type of hat to haul, e.g. vz, lxc, or docker")
>>>>>>  parser.add_argument("id", help="ID of what to haul")
>>>>>>  parser.add_argument("--to", help="IP where to haul")
>>>>>>  parser.add_argument("--fdrpc", help="File descriptor of rpc socket", type=int, required=True)
>>>>>> diff --git a/phaul/fs_haul_subtree.py b/phaul/fs_haul_subtree.py
>>>>>> index a9bd559..e20ad1b 100644
>>>>>> --- a/phaul/fs_haul_subtree.py
>>>>>> +++ b/phaul/fs_haul_subtree.py
>>>>>> @@ -11,29 +11,38 @@ import logging
>>>>>>  rsync_log_file = "rsync.log"
>>>>>>
>>>>>>  class p_haul_fs:
>>>>>> -     def __init__(self, subtree_path):
>>>>>> -             logging.info("Initialized subtree FS hauler (%s)", subtree_path)
>>>>>> -             self.__root = subtree_path
>>>>>> +     def __init__(self, subtree_paths):
>>>>>> +             self.__roots = []
>>>>>> +             for path in subtree_paths:
>>>>>> +                     logging.info("Initialized subtree FS hauler (%s)", path)
>>>>>> +                     self.__roots.append(path)
>>>>>> +
>>>>>>               self.__thost = None
>>>>>>
>>>>>>       def set_options(self, opts):
>>>>>>               self.__thost = opts["to"]
>>>>>>
>>>>>> +     def set_target_host(self, thost):
>>>>>> +             self.__thost = thost
>>>>>> +
>>>>>>       def set_work_dir(self, wdir):
>>>>>>               self.__wdir = wdir
>>>>>>
>>>>>>       def __run_rsync(self):
>>>>>>               logf = open(os.path.join(self.__wdir, rsync_log_file), "w+")
>>>>>> -             dst = "%s:%s" % (self.__thost, os.path.dirname(self.__root))
>>>>>>
>>>>>> -             # First rsync might be very long. Wait for it not
>>>>>> -             # to produce big pause between the 1st pre-dump and
>>>>>> -             # .stop_migration
>>>>>> +             for dir_name in self.__roots:
>>>>>> +
>>>>>> +                     dst = "%s:%s" % (self.__thost, os.path.dirname(dir_name))
>>>>>> +
>>>>>> +                     # First rsync might be very long. Wait for it not
>>>>>> +                     # to produce big pause between the 1st pre-dump and
>>>>>> +                     # .stop_migration
>>>>>>
>>>>>> -             ret = sp.call(["rsync", "-a", self.__root, dst],
>>>>>> +                     ret = sp.call(["rsync", "-a", dir_name, dst],
>>>>>>                               stdout = logf, stderr = logf)
>>>>>> -             if ret != 0:
>>>>>> -                     raise Exception("Rsync failed")
>>>>>> +                     if ret != 0:
>>>>>> +                             raise Exception("Rsync failed")
>>>>>>
>>>>>>       def start_migration(self):
>>>>>>               logging.info("Starting FS migration")
>>>>>> diff --git a/phaul/htype.py b/phaul/htype.py
>>>>>> index f3a4774..bee49b4 100644
>>>>>> --- a/phaul/htype.py
>>>>>> +++ b/phaul/htype.py
>>>>>> @@ -11,6 +11,7 @@ __haul_modules = {
>>>>>>       "vz": "p_haul_vz",
>>>>>>       "pid": "p_haul_pid",
>>>>>>       "lxc": "p_haul_lxc",
>>>>>> +     "docker": "p_haul_docker",
>>>>>>  }
>>>>>>
>>>>>>  def __get(id):
>>>>>> diff --git a/phaul/images.py b/phaul/images.py
>>>>>> index 57dca59..e48f96f 100644
>>>>>> --- a/phaul/images.py
>>>>>> +++ b/phaul/images.py
>>>>>> @@ -145,7 +145,8 @@ class phaul_images:
>>>>>>               tf = img_tar(sk, cdir)
>>>>>>
>>>>>>               logging.info("\tPack")
>>>>>> -             for img in filter(lambda x: x.endswith(".img"), os.listdir(cdir)):
>>>>>> +             # .json file is needed for docker, i.e., descriptor.json
>>>>>> +             for img in filter(lambda x: x.endswith(('.img', '.json')) , os.listdir(cdir)):
>>>>>
>>>>> Why do we include .json files from images dir? Where do the come from?
>>>>
>>>> This descriptors.json is generated by "docker checkpoint". I copied
>>>> its content here
>>>>
>>>>  cat /var/run/docker/execdriver/native/4fe6ae42044ecb216788a2dc8cae900f9bd3ca93b7e84a1cee56acfe34c46e32/criu.image/descriptors.json
>>>> ["/dev/null","pipe:[1095038]","pipe:[1095039]"]
>>>>
>>>> "docker restore" will fail without this descriptors.json. Since this
>>>> file exists with all other criu images, we can use sync_image to send
>>>> the file.
>>>
>>> OK. Would you feed one into the transfer blob via the put_meta_images() callback?
>>>
>>>>>
>>>>>>                       tf.add(img)
>>>>>>
>>>>>>               logging.info("\tAdd htype images")
>>>>>> diff --git a/phaul/iters.py b/phaul/iters.py
>>>>>> index 9be4e97..00b2a02 100644
>>>>>> --- a/phaul/iters.py
>>>>>> +++ b/phaul/iters.py
>>>>>> @@ -113,7 +113,7 @@ class phaul_iter_worker:
>>>>>>               if self.pre_dump == PRE_DUMP_AUTO_DETECT:
>>>>>>                       # pre-dump auto-detection
>>>>>>                       try:
>>>>>> -                             self.pre_dump = self.pre_dump_check()
>>>>>> +                             self.pre_dump = (self.pre_dump_check() and self.htype.can_pre_dump())
>>>>>>                               logging.info("\t`- Auto %s" % (self.pre_dump and 'enabled' or 'disabled'))
>>>>>>                       except:
>>>>>>                               # The available criu seems to not
>>>>>> @@ -121,6 +121,11 @@ class phaul_iter_worker:
>>>>>>                               self.pre_dump = PRE_DUMP_DISABLE
>>>>>>                               logging.info("\t`- Auto detection not possible "
>>>>>>                                               "- Disabled")
>>>>>> +             elif self.pre_dump == PRE_DUMP_DISABLE:
>>>>>> +                     logging.info("\t`- Command-line disabled")
>>>>>> +             elif self.htype.can_pre_dump() == False:
>>>>>> +                     self.pre_dump = False
>>>>>> +                     logging.info("\t`- Type does not support pre-dump")
>>>>>
>>>>> Why is this elif elif part required?
>>>>
>>>> This elif means if pre_dump is set true in command line, we need to
>>>> further check if the phaul type supports pre_dump.
>>>
>>> But you don't -- the call for self.htype.can_pre_dump() is only done above,
>>> when pre_dump is set to AUTO_DETECT.
>>>
>>> I would leave the cases then pre_dump is set explicitly alone, so that we
>>> could _force_ pre_dump-s with command-line.
>>>
>>>>>
>>>>>>               else:
>>>>>>                       logging.info("\t`- Command-line %s" % (self.pre_dump and 'enabled' or 'disabled'))
>>>>>>
>>>>>> diff --git a/phaul/p_haul_docker.py b/phaul/p_haul_docker.py
>>>>>> new file mode 100644
>>>>>> index 0000000..d2bb1e3
>>>>>> --- /dev/null
>>>>>> +++ b/phaul/p_haul_docker.py
>>>>>> @@ -0,0 +1,158 @@
>>>>>> +#
>>>>>> +# Docker container hauler
>>>>>> +#
>>>>>> +
>>>>>> +import os
>>>>>> +import logging
>>>>>> +import time
>>>>>> +import fs_haul_subtree
>>>>>> +import pycriu.rpc
>>>>>> +import json
>>>>>> +from pprint import pprint
>>>>>> +import subprocess as sp
>>>>>> +from subprocess import PIPE
>>>>>> +
>>>>>> +# TODO use docker-py
>>>>>> +# import docker
>>>>>> +
>>>>>> +# Some constants for docker
>>>>>> +name = "docker"
>>>>>> +docker_exec = "/usr/bin/docker-1.9.0-dev"
>>>>>> +docker_dir = "/var/lib/docker/"
>>>>>> +docker_run_meta_dir = "/var/run/docker/execdriver/native"
>>>>>> +
>>>>>> +class p_haul_type:
>>>>>> +     def __init__(self, ctid):
>>>>>> +
>>>>>> +             # TODO ctid must > 3 digit; with docker-py, we can also resolve
>>>>>> +             #         container name
>>>>>> +             if len(ctid) < 3:
>>>>>> +                     raise Exception("Docker container ID must be > 3 digits")
>>>>>> +
>>>>>> +             self._ctid = ctid
>>>>>> +             self._ct_rootfs = ""
>>>>>> +
>>>>>> +     def get_driver_name(self):
>>>>>> +             return name
>>>>>> +
>>>>>> +     def init_src(self):
>>>>>> +             self.full_ctid = self.get_full_ctid()
>>>>>> +             self.__load_ct_config(docker_dir)
>>>>>> +
>>>>>> +     def init_dst(self):
>>>>>> +             pass
>>>>>> +
>>>>>> +     def adjust_criu_req(self, req):
>>>>>> +             """Add module-specific options to criu request"""
>>>>>> +             pass
>>>>>> +
>>>>>> +     def root_task_pid(self):
>>>>>> +             # Do we need this for Docker?
>>>>>> +             return self.full_ctid
>>>>>> +
>>>>>> +     def __load_ct_config(self, path):
>>>>>> +
>>>>>> +             # Each docker container has 3 directories that need to be
>>>>>> +             # migrated: (1) root filesystem, (2) container configuration,
>>>>>> +             # (3) runtime meta state
>>>>>> +             self._ct_rootfs = os.path.join(docker_dir, "aufs/mnt", self.full_ctid)
>>>>>> +             self._ct_config_dir = os.path.join(docker_dir, "containers", self.full_ctid)
>>>>>> +             self._ct_run_meta_dir = os.path.join(docker_run_meta_dir, self.full_ctid)
>>>>>> +             logging.info("Container rootfs: %s", self._ct_rootfs)
>>>>>> +             logging.info("Container config: %s", self._ct_config_dir)
>>>>>> +             logging.info("Container meta: %s", self._ct_run_meta_dir)
>>>>>> +
>>>>>> +     def set_options(self, opts):
>>>>>> +             pass
>>>>>> +
>>>>>> +     # Remove any specific FS setup
>>>>>> +     def umount(self):
>>>>>> +             pass
>>>>>> +
>>>>>> +     def get_fs(self, fs_sk=None):
>>>>>> +             # use rsync for rootfs and configuration directories
>>>>>> +             return fs_haul_subtree.p_haul_fs([self._ct_rootfs, self._ct_config_dir])
>>>>>> +
>>>>>> +     def get_fs_receiver(self, fs_sk=None):
>>>>>> +             return None
>>>>>> +
>>>>>> +     def get_full_ctid(self):
>>>>>> +             dir_name_list = os.listdir(os.path.join(docker_dir, "containers"))
>>>>>> +
>>>>>> +             full_id = ""
>>>>>> +             for name in dir_name_list:
>>>>>> +                     name = name.rsplit("/")
>>>>>> +                     if (name[0].find(self._ctid) == 0):
>>>>>> +                             full_id = name[0]
>>>>>> +                             break
>>>>>> +
>>>>>> +             if full_id != "":
>>>>>> +                     return full_id
>>>>>> +             else:
>>>>>> +                     raise Exception("Can not find container fs")
>>>>>> +
>>>>>> +     def final_dump(self, pid, img, ccon, fs):
>>>>>> +             logging.info("Dump docker container %s", pid)
>>>>>> +
>>>>>> +             # TODO: docker API does not have checkpoint right now
>>>>>> +             # cli.checkpoint() so we have to use the command line
>>>>>> +             # cli = docker.Client(base_url='unix://var/run/docker.sock')
>>>>>> +             # output = cli.info()
>>>>>> +             # call docker API
>>>>>> +
>>>>>> +             logf = open("/tmp/docker_checkpoint.log", "w+")
>>>>>> +             image_path_opt = "--image-dir=" + img.image_dir()
>>>>>> +             ret = sp.call([docker_exec, "checkpoint", image_path_opt, self._ctid],
>>>>>> +                     stdout = logf, stderr = logf)
>>>>>> +             if ret != 0:
>>>>>> +                     raise Exception("docker checkpoint failed")
>>>>>> +     #
>>>>>> +     # Meta-images for docker -- /var/run/docker
>>>>>> +     #
>>>>>> +     def get_meta_images(self, path):
>>>>>> +             # Send the meta state file with criu images
>>>>>> +             return [(os.path.join(self._ct_run_meta_dir, "state.json"), "state.json")]
>>>>>> +
>>>>>> +     def put_meta_images(self, dir):
>>>>>> +             # Create docker runtime meta dir on dst side
>>>>>> +             with open(os.path.join(dir, "state.json")) as data_file:
>>>>>> +                     data = json.load(data_file)
>>>>>> +             self.full_ctid=data["id"]
>>>>>> +
>>>>>> +             self.__load_ct_config(docker_dir)
>>>>>> +             os.makedirs(self._ct_run_meta_dir)
>>>>>> +             pd = sp.Popen(["cp", os.path.join(dir, "state.json"), self._ct_run_meta_dir], stdout = PIPE)
>>>>>> +             status = pd.wait()
>>>>>> +
>>>>>> +     def kill_last_docker_daemon(self):
>>>>>> +             p = sp.Popen(['pgrep', '-l' , docker_exec], stdout=sp.PIPE)
>>>>>> +             out, err = p.communicate()
>>>>>> +
>>>>>> +             for line in out.splitlines():
>>>>>> +                     line = bytes.decode(line)
>>>>>> +                     pid = int(line.split(None, 1)[0])
>>>>>> +                     os.kill(pid, signal.SIGKILL)
>>>>>> +
>>>>>> +     def final_restore(self, img, criu):
>>>>>> +             logf = open("/tmp/docker_restore.log", "w+")
>>>>>> +
>>>>>> +             # Kill any previous docker daemon in order to reload the
>>>>>> +             # status of the migrated container
>>>>>> +             self.kill_last_docker_daemon()
>>>>>> +
>>>>>> +             # start docker daemon in background
>>>>>> +             daemon = sp.Popen([docker_exec, "daemon", "-s", "aufs"],
>>>>>> +                              stdout = logf, stderr = logf)
>>>>>> +             # daemon.wait() TODO: docker daemon not return
>>>>>> +             time.sleep(2)
>>>>>> +
>>>>>> +             image_path_opt = "--image-dir=" + img.image_dir()
>>>>>> +             ret = sp.call([docker_exec, "restore", image_path_opt, self._ctid],
>>>>>> +                                             stdout = logf, stderr = logf)
>>>>>> +             if ret != 0:
>>>>>> +                     raise Exception("docker restore failed")
>>>>>> +
>>>>>> +     def can_pre_dump(self):
>>>>>> +             # XXX: Do not do predump for docker right now. Add page-server
>>>>>> +             #       to docker C/R API, then we can enable the pre-dump
>>>>>> +             return False
>>>>>> diff --git a/phaul/p_haul_pid.py b/phaul/p_haul_pid.py
>>>>>> index e354dff..43af654 100644
>>>>>> --- a/phaul/p_haul_pid.py
>>>>>> +++ b/phaul/p_haul_pid.py
>>>>>> @@ -94,3 +94,6 @@ class p_haul_type:
>>>>>>       # Get list of veth pairs if any
>>>>>>       def veths(self):
>>>>>>               return []
>>>>>> +
>>>>>> +     def can_pre_dump(self):
>>>>>> +             return True
>>>>>> diff --git a/phaul/p_haul_vz.py b/phaul/p_haul_vz.py
>>>>>> index 903006d..e346bdf 100644
>>>>>> --- a/phaul/p_haul_vz.py
>>>>>> +++ b/phaul/p_haul_vz.py
>>>>>> @@ -244,6 +244,9 @@ class p_haul_type:
>>>>>>               return True
>>>>>>
>>>>>>
>>>>>> +     def can_pre_dump(self):
>>>>>> +             return True
>>>>>> +
>>>>>>  def parse_vz_config(body):
>>>>>>       """Parse shell-like virtuozzo config file"""
>>>>>>
>>>>>> diff --git a/phaul/service.py b/phaul/service.py
>>>>>> index a03b43e..507d171 100644
>>>>>> --- a/phaul/service.py
>>>>>> +++ b/phaul/service.py
>>>>>> @@ -72,7 +72,8 @@ class phaul_service:
>>>>>>       def rpc_start_iter(self):
>>>>>>               self.dump_iter_index += 1
>>>>>>               self.img.new_image_dir()
>>>>>> -             self.start_page_server()
>>>>>> +             if self.htype.get_driver_name() != "docker" :
>>>>>> +                     self.start_page_server()
>>>>>
>>>>> Explicit docker check again. What bad happens if you let the page server
>>>>> spawn?
>>>>
>>>> Here is the error message after remoing the check for docker:
>>>>
>>>> 17:50:24.551:     Page server started at 3833
>>>> 17:50:32.329: Started images server
>>>> 17:50:32.333: Exception in untar_thread
>>>> Traceback (most recent call last):
>>>>   File "/root/development/p.haul/phaul/images.py", line 42, in run
>>>>     tf = tarfile.open(mode="r|", fileobj=util.fileobj_wrap(self.__sk))
>>>>   File "/usr/lib/python2.7/tarfile.py", line 1690, in open
>>>>     **kwargs)
>>>>   File "/usr/lib/python2.7/tarfile.py", line 1574, in __init__
>>>>     self.firstmember = self.next()
>>>>   File "/usr/lib/python2.7/tarfile.py", line 2335, in next
>>>>     raise ReadError(str(e))
>>>> ReadError: bad checksum
>>>
>>> O_o But this has (should have) nothing to do with page-server, it's
>>> just some tarfile internal stuff.
>>>
>>>> 17:50:32.348: Waiting for images to unpack
>>>> 17:50:32.349: Restoring from images
>>>>
>>>> I doubt that is is because there is not pre_dump for docker, so the
>>>> page_server does not receive any criu image. Is this correct?
>>>
>>> AFAIU yes, you do final dump on disk, so page server is reqlly unneeded
>>> here. Please, see my next commend about what to do with it.
>>>
>>>>>
>>>>> BTW, a question to Nikita -- I don't see in p_haul_vz.py that we do final
>>>>> dump go via page-server. Do we?
>>>>
>>>> >From my understanding, no final dump may go via page-server. The criu
>>>> images are sent using tar/untar via the mem_sk.
>>>
>>> OK, so what we have here is -- final dump for everyone is done w/o the
>>> page server. That's a pity we should fix, but for now let's make yet
>>> another (temporary) htype method 'dump_need_ps()' denoting that final
>>> dump does or does not go via page-server and start or not this guy
>>> respectively. OK? Some time soon this will be removed, but for now
>>> let's make it w/o explicit "name == docker" checks.
>>
>> This idea may be implemented without adding dump_need_ps() for each htype.
>> Instead, can we add a parameter rpc_start_iter to denote if
>> page_server should be started or not? It looks like
> 
> Continued from last email.
> 
>     while self.pre_dump:
>             self.target_host.start_iter(true)
>             ....
> 
>     logging.info("Final dump and restore")
>     self.target_host.start_iter(false)

Yes, I like the idea, but remember that p_haul_pid.py needs page-server even
for the final dump stage, so passing just False all the time here would be
incorrect.

-- Pavel


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