summaryrefslogtreecommitdiffstats
path: root/geo-replication/syncdaemon/monitor.py
blob: 14e77aef27e1894d9369325753e92cd1f9b22c45 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
#
# Copyright (c) 2011-2014 Red Hat, Inc. <http://www.redhat.com>
# This file is part of GlusterFS.

# This file is licensed to you under your choice of the GNU Lesser
# General Public License, version 3 or any later version (LGPLv3 or
# later), or the GNU General Public License, version 2 (GPLv2), in all
# cases as published by the Free Software Foundation.
#

import os
import sys
import time
import signal
import logging
import xml.etree.ElementTree as XET
from threading import Lock
from errno import ECHILD, ESRCH
import random

from resource import SSH
import gsyncdconfig as gconf
import libgfchangelog
from rconf import rconf
from syncdutils import select, waitpid, errno_wrap, lf, grabpidfile
from syncdutils import set_term_handler, GsyncdError
from syncdutils import Thread, finalize, Volinfo, VolinfoFromGconf
from syncdutils import gf_event, EVENT_GEOREP_FAULTY, get_up_nodes
from gsyncdstatus import GeorepStatus, set_monitor_status
from syncdutils import unshare_propagation_supported
import py2py3
from py2py3 import pipe

ParseError = XET.ParseError if hasattr(XET, 'ParseError') else SyntaxError


def get_subvol_num(brick_idx, vol, hot):
    tier = vol.is_tier()
    disperse_count = vol.disperse_count(tier, hot)
    replica_count = vol.replica_count(tier, hot)
    distribute_count = vol.distribution_count(tier, hot)
    gconf.setconfig("master-distribution-count", distribute_count)

    if (tier and not hot):
        brick_idx = brick_idx - vol.get_hot_bricks_count(tier)

    subvol_size = disperse_count if disperse_count > 0 else replica_count
    cnt = int((brick_idx + 1) / subvol_size)
    rem = (brick_idx + 1) % subvol_size
    if rem > 0:
        cnt = cnt + 1

    if (tier and hot):
        return "hot_" + str(cnt)
    elif (tier and not hot):
        return "cold_" + str(cnt)
    else:
        return str(cnt)


class Monitor(object):

    """class which spawns and manages gsyncd workers"""

    ST_INIT = 'Initializing...'
    ST_STARTED = 'Started'
    ST_STABLE = 'Active'
    ST_FAULTY = 'Faulty'
    ST_INCON = 'inconsistent'
    _ST_ORD = [ST_STABLE, ST_INIT, ST_FAULTY, ST_INCON]

    def __init__(self):
        self.lock = Lock()
        self.state = {}
        self.status = {}

    @staticmethod
    def terminate():
        # relax one SIGTERM by setting a handler that sets back
        # standard handler
        set_term_handler(lambda *a: set_term_handler())
        # give a chance to graceful exit
        errno_wrap(os.kill, [-os.getpid(), signal.SIGTERM], [ESRCH])

    def monitor(self, w, argv, cpids, slave_vol, slave_host, master,
                suuid, slavenodes):
        """the monitor loop

        Basic logic is a blantantly simple blunt heuristics:
        if spawned client survives 60 secs, it's considered OK.
        This servers us pretty well as it's not vulneralbe to
        any kind of irregular behavior of the child...

        ... well, except for one: if children is hung up on
        waiting for some event, it can survive aeons, still
        will be defunct. So we tweak the above logic to
        expect the worker to send us a signal within 60 secs
        (in the form of closing its end of a pipe). The worker
        does this when it's done with the setup stage
        ready to enter the service loop (note it's the setup
        stage which is vulnerable to hangs -- the full
        blown worker blows up on EPIPE if the net goes down,
        due to the keep-alive thread)
        """
        if not self.status.get(w[0]['dir'], None):
            self.status[w[0]['dir']] = GeorepStatus(gconf.get("state-file"),
                                                    w[0]['host'],
                                                    w[0]['dir'],
                                                    w[0]['uuid'],
                                                    master,
                                                    "%s::%s" % (slave_host,
                                                                slave_vol))
        ret = 0

        def nwait(p, o=0):
            try:
                p2, r = waitpid(p, o)
                if not p2:
                    return
                return r
            except OSError as e:
                # no child process, this happens if the child process
                # already died and has been cleaned up
                if e.errno == ECHILD:
                    return -1
                else:
                    raise

        def exit_signalled(s):
            """ child terminated due to receipt of SIGUSR1 """
            return (os.WIFSIGNALED(s) and (os.WTERMSIG(s) == signal.SIGUSR1))

        def exit_status(s):
            if os.WIFEXITED(s):
                return os.WEXITSTATUS(s)
            return 1

        conn_timeout = gconf.get("connection-timeout")
        while ret in (0, 1):
            remote_user, remote_host = w[1][0].split("@")
            remote_id = w[1][1]
            # Check the status of the connected slave node
            # If the connected slave node is down then try to connect to
            # different up node.
            current_slave_host = remote_host
            slave_up_hosts = get_up_nodes(slavenodes, gconf.get("ssh-port"))

            if (current_slave_host, remote_id) not in slave_up_hosts:
                if len(slave_up_hosts) > 0:
                    remote_new = random.choice(slave_up_hosts)
                    remote_host = "%s@%s" % (remote_user, remote_new[0])
                    remote_id = remote_new[1]

            # Spawn the worker in lock to avoid fd leak
            self.lock.acquire()

            self.status[w[0]['dir']].set_worker_status(self.ST_INIT)
            logging.info(lf('starting gsyncd worker',
                            brick=w[0]['dir'],
                            slave_node=remote_host))

            pr, pw = pipe()
            cpid = os.fork()
            if cpid == 0:
                os.close(pr)

                args_to_worker = argv + [
                    'worker',
                    rconf.args.master,
                    rconf.args.slave,
                    '--feedback-fd', str(pw),
                    '--local-path', w[0]['dir'],
                    '--local-node', w[0]['host'],
                    '--local-node-id', w[0]['uuid'],
                    '--slave-id', suuid,
                    '--subvol-num', str(w[2]),
                    '--resource-remote', remote_host,
                    '--resource-remote-id', remote_id
                ]

                if rconf.args.config_file is not None:
                    args_to_worker += ['-c', rconf.args.config_file]

                if w[3]:
                    args_to_worker.append("--is-hottier")

                if rconf.args.debug:
                    args_to_worker.append("--debug")

                access_mount = gconf.get("access-mount")
                if access_mount:
                    os.execv(sys.executable, args_to_worker)
                else:
                    if unshare_propagation_supported():
                        logging.debug("Worker would mount volume privately")
                        unshare_cmd = ['unshare', '-m', '--propagation',
                                       'private']
                        cmd = unshare_cmd + args_to_worker
                        os.execvp("unshare", cmd)
                    else:
                        logging.debug("Mount is not private. It would be lazy"
                                      " umounted")
                        os.execv(sys.executable, args_to_worker)

            cpids.add(cpid)
            os.close(pw)

            self.lock.release()

            t0 = time.time()
            so = select((pr,), (), (), conn_timeout)[0]
            os.close(pr)

            if so:
                ret = nwait(cpid, os.WNOHANG)

                if ret is not None:
                    logging.info(lf("worker died before establishing "
                                    "connection",
                                    brick=w[0]['dir']))
                else:
                    logging.debug("worker(%s) connected" % w[0]['dir'])
                    while time.time() < t0 + conn_timeout:
                        ret = nwait(cpid, os.WNOHANG)

                        if ret is not None:
                            logging.info(lf("worker died in startup phase",
                                            brick=w[0]['dir']))
                            break

                        time.sleep(1)
            else:
                logging.info(
                    lf("Worker not confirmed after wait, aborting it. "
                       "Gsyncd invocation on remote slave via SSH or "
                       "gluster master mount might have hung. Please "
                       "check the above logs for exact issue and check "
                       "master or slave volume for errors. Restarting "
                       "master/slave volume accordingly might help.",
                       brick=w[0]['dir'],
                       timeout=conn_timeout))
                errno_wrap(os.kill, [cpid, signal.SIGKILL], [ESRCH])
                ret = nwait(cpid)
            if ret is None:
                ret = nwait(cpid)
            if exit_signalled(ret):
                ret = 0
            else:
                ret = exit_status(ret)
                if ret in (0, 1):
                    self.status[w[0]['dir']].set_worker_status(self.ST_FAULTY)
                    gf_event(EVENT_GEOREP_FAULTY,
                             master_volume=master.volume,
                             master_node=w[0]['host'],
                             master_node_id=w[0]['uuid'],
                             slave_host=slave_host,
                             slave_volume=slave_vol,
                             current_slave_host=current_slave_host,
                             brick_path=w[0]['dir'])
            time.sleep(10)
        self.status[w[0]['dir']].set_worker_status(self.ST_INCON)
        return ret

    def multiplex(self, wspx, suuid, slave_vol, slave_host, master, slavenodes):
        argv = [os.path.basename(sys.executable), sys.argv[0]]

        cpids = set()
        ta = []
        for wx in wspx:
            def wmon(w):
                cpid, _ = self.monitor(w, argv, cpids, slave_vol,
                                       slave_host, master, suuid, slavenodes)
                time.sleep(1)
                self.lock.acquire()
                for cpid in cpids:
                    errno_wrap(os.kill, [cpid, signal.SIGKILL], [ESRCH])
                self.lock.release()
                finalize(exval=1)
            t = Thread(target=wmon, args=[wx])
            t.start()
            ta.append(t)

        # monitor status was being updated in each monitor thread. It
        # should not be done as it can cause deadlock for a worker start.
        # set_monitor_status uses flock to synchronize multple instances
        # updating the file. Since each monitor thread forks worker,
        # these processes can hold the reference to fd of status
        # file causing deadlock to workers which starts later as flock
        # will not be release until all references to same fd is closed.
        # It will also cause fd leaks.

        self.lock.acquire()
        set_monitor_status(gconf.get("state-file"), self.ST_STARTED)
        self.lock.release()
        for t in ta:
            t.join()


def distribute(master, slave):
    if rconf.args.use_gconf_volinfo:
        mvol = VolinfoFromGconf(master.volume, master=True)
    else:
        mvol = Volinfo(master.volume, master.host, master=True)
    logging.debug('master bricks: ' + repr(mvol.bricks))
    prelude = []
    slave_host = None
    slave_vol = None

    prelude = [gconf.get("ssh-command")] + \
        gconf.get("ssh-options").split() + \
        ["-p", str(gconf.get("ssh-port"))] + \
        [slave.remote_addr]

    logging.debug('slave SSH gateway: ' + slave.remote_addr)

    if rconf.args.use_gconf_volinfo:
        svol = VolinfoFromGconf(slave.volume, master=False)
    else:
        svol = Volinfo(slave.volume, "localhost", prelude, master=False)

    sbricks = svol.bricks
    suuid = svol.uuid
    slave_host = slave.remote_addr.split('@')[-1]
    slave_vol = slave.volume

    # save this xattr for the session delete command
    old_stime_xattr_prefix = gconf.get("stime-xattr-prefix", None)
    new_stime_xattr_prefix = "trusted.glusterfs." + mvol.uuid + "." + \
                             svol.uuid
    if not old_stime_xattr_prefix or \
       old_stime_xattr_prefix != new_stime_xattr_prefix:
        gconf.setconfig("stime-xattr-prefix", new_stime_xattr_prefix)

    logging.debug('slave bricks: ' + repr(sbricks))

    slavenodes = set((b['host'], b["uuid"]) for b in sbricks)
    rap = SSH.parse_ssh_address(slave)
    slaves = [(rap['user'] + '@' + h[0], h[1]) for h in slavenodes]

    workerspex = []
    for idx, brick in enumerate(mvol.bricks):
        if rconf.args.local_node_id == brick['uuid']:
            is_hot = mvol.is_hot(":".join([brick['host'], brick['dir']]))
            workerspex.append((brick,
                               slaves[idx % len(slaves)],
                               get_subvol_num(idx, mvol, is_hot),
                               is_hot))
    logging.debug('worker specs: ' + repr(workerspex))
    return workerspex, suuid, slave_vol, slave_host, master, slavenodes


def monitor(local, remote):
    # Check if gsyncd restarted in pause state. If
    # yes, send SIGSTOP to negative of monitor pid
    # to go back to pause state.
    if rconf.args.pause_on_start:
        errno_wrap(os.kill, [-os.getpid(), signal.SIGSTOP], [ESRCH])

    """oh yeah, actually Monitor is used as singleton, too"""
    return Monitor().multiplex(*distribute(local, remote))


def startup(go_daemon=True):
    """set up logging, pidfile grabbing, daemonization"""
    pid_file = gconf.get("pid-file")
    if not grabpidfile():
        sys.stderr.write("pidfile is taken, exiting.\n")
        sys.exit(2)
    rconf.pid_file_owned = True

    if not go_daemon:
        return

    x, y = pipe()
    cpid = os.fork()
    if cpid:
        os.close(x)
        sys.exit()
    os.close(y)
    os.setsid()
    dn = os.open(os.devnull, os.O_RDWR)
    for f in (sys.stdin, sys.stdout, sys.stderr):
        os.dup2(dn, f.fileno())

    if not grabpidfile(pid_file + '.tmp'):
        raise GsyncdError("cannot grab temporary pidfile")

    os.rename(pid_file + '.tmp', pid_file)

    # wait for parent to terminate
    # so we can start up with
    # no messing from the dirty
    # ol' bustard
    select((x,), (), ())
    os.close(x)