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Diffstat (limited to '')
| -rw-r--r-- | qa/tasks/cephfs/test_client_limits.py | 330 |
1 files changed, 330 insertions, 0 deletions
diff --git a/qa/tasks/cephfs/test_client_limits.py b/qa/tasks/cephfs/test_client_limits.py new file mode 100644 index 00000000..613a405a --- /dev/null +++ b/qa/tasks/cephfs/test_client_limits.py @@ -0,0 +1,330 @@ + +""" +Exercise the MDS's behaviour when clients and the MDCache reach or +exceed the limits of how many caps/inodes they should hold. +""" + +import logging +from textwrap import dedent +from unittest import SkipTest +from teuthology.orchestra.run import CommandFailedError +from tasks.ceph_test_case import TestTimeoutError +from tasks.cephfs.cephfs_test_case import CephFSTestCase, needs_trimming +from tasks.cephfs.fuse_mount import FuseMount +import os + + +log = logging.getLogger(__name__) + + +# Arbitrary timeouts for operations involving restarting +# an MDS or waiting for it to come up +MDS_RESTART_GRACE = 60 + +# Hardcoded values from Server::recall_client_state +CAP_RECALL_RATIO = 0.8 +CAP_RECALL_MIN = 100 + + +class TestClientLimits(CephFSTestCase): + REQUIRE_KCLIENT_REMOTE = True + CLIENTS_REQUIRED = 2 + + def _test_client_pin(self, use_subdir, open_files): + """ + When a client pins an inode in its cache, for example because the file is held open, + it should reject requests from the MDS to trim these caps. The MDS should complain + to the user that it is unable to enforce its cache size limits because of this + objectionable client. + + :param use_subdir: whether to put test files in a subdir or use root + """ + + self.config_set('mds', 'mds_cache_memory_limit', "1K") + self.config_set('mds', 'mds_recall_max_caps', int(open_files/2)) + self.config_set('mds', 'mds_recall_warning_threshold', open_files) + + mds_min_caps_per_client = int(self.config_get('mds.a', "mds_min_caps_per_client")) + self.config_set('mds', 'mds_min_caps_working_set', mds_min_caps_per_client) + mds_recall_warning_decay_rate = float(self.config_get('mds.a', "mds_recall_warning_decay_rate")) + self.assertGreaterEqual(open_files, mds_min_caps_per_client) + + mount_a_client_id = self.mount_a.get_global_id() + path = "subdir" if use_subdir else "." + open_proc = self.mount_a.open_n_background(path, open_files) + + # Client should now hold: + # `open_files` caps for the open files + # 1 cap for root + # 1 cap for subdir + self.wait_until_equal(lambda: self.get_session(mount_a_client_id)['num_caps'], + open_files + (2 if use_subdir else 1), + timeout=600, + reject_fn=lambda x: x > open_files + 2) + + # MDS should not be happy about that, as the client is failing to comply + # with the SESSION_RECALL messages it is being sent + self.wait_for_health("MDS_CLIENT_RECALL", mds_recall_warning_decay_rate*2) + + # We can also test that the MDS health warning for oversized + # cache is functioning as intended. + self.wait_for_health("MDS_CACHE_OVERSIZED", mds_recall_warning_decay_rate*2) + + # When the client closes the files, it should retain only as many caps as allowed + # under the SESSION_RECALL policy + log.info("Terminating process holding files open") + open_proc.stdin.close() + try: + open_proc.wait() + except CommandFailedError: + # We killed it, so it raises an error + pass + + # The remaining caps should comply with the numbers sent from MDS in SESSION_RECALL message, + # which depend on the caps outstanding, cache size and overall ratio + def expected_caps(): + num_caps = self.get_session(mount_a_client_id)['num_caps'] + if num_caps <= mds_min_caps_per_client: + return True + else: + return False + + self.wait_until_true(expected_caps, timeout=60) + + @needs_trimming + def test_client_pin_root(self): + self._test_client_pin(False, 400) + + @needs_trimming + def test_client_pin(self): + self._test_client_pin(True, 800) + + @needs_trimming + def test_client_pin_mincaps(self): + self._test_client_pin(True, 200) + + def test_client_min_caps_working_set(self): + """ + When a client has inodes pinned in its cache (open files), that the MDS + will not warn about the client not responding to cache pressure when + the number of caps is below mds_min_caps_working_set. + """ + + # Set MDS cache memory limit to a low value that will make the MDS to + # ask the client to trim the caps. + cache_memory_limit = "1K" + open_files = 400 + + self.config_set('mds', 'mds_cache_memory_limit', cache_memory_limit) + self.config_set('mds', 'mds_recall_max_caps', int(open_files/2)) + self.config_set('mds', 'mds_recall_warning_threshold', open_files) + self.config_set('mds', 'mds_min_caps_working_set', open_files*2) + + mds_min_caps_per_client = int(self.config_get('mds.a', "mds_min_caps_per_client")) + mds_recall_warning_decay_rate = float(self.config_get('mds.a', "mds_recall_warning_decay_rate")) + self.assertGreaterEqual(open_files, mds_min_caps_per_client) + + mount_a_client_id = self.mount_a.get_global_id() + self.mount_a.open_n_background("subdir", open_files) + + # Client should now hold: + # `open_files` caps for the open files + # 1 cap for root + # 1 cap for subdir + self.wait_until_equal(lambda: self.get_session(mount_a_client_id)['num_caps'], + open_files + 2, + timeout=600, + reject_fn=lambda x: x > open_files + 2) + + # We can also test that the MDS health warning for oversized + # cache is functioning as intended. + self.wait_for_health("MDS_CACHE_OVERSIZED", mds_recall_warning_decay_rate*2) + + try: + # MDS should not be happy about that but it's not sending + # MDS_CLIENT_RECALL warnings because the client's caps are below + # mds_min_caps_working_set. + self.wait_for_health("MDS_CLIENT_RECALL", mds_recall_warning_decay_rate*2) + except TestTimeoutError: + pass + else: + raise RuntimeError("expected no client recall warning") + + def test_cap_acquisition_throttle_readdir(self): + """ + Mostly readdir acquires caps faster than the mds recalls, so the cap + acquisition via readdir is throttled by retrying the readdir after + a fraction of second (0.5) by default when throttling condition is met. + """ + + max_caps_per_client = 500 + cap_acquisition_throttle = 250 + + self.config_set('mds', 'mds_max_caps_per_client', max_caps_per_client) + self.config_set('mds', 'mds_session_cap_acquisition_throttle', cap_acquisition_throttle) + + # Create 1500 files split across 6 directories, 250 each. + for i in range(1, 7): + self.mount_a.create_n_files("dir{0}/file".format(i), cap_acquisition_throttle, sync=True) + + mount_a_client_id = self.mount_a.get_global_id() + + # recursive readdir + self.mount_a.run_shell_payload("find | wc") + + # validate cap_acquisition decay counter after readdir to exceed throttle count i.e 250 + cap_acquisition_value = self.get_session(mount_a_client_id)['cap_acquisition']['value'] + self.assertGreaterEqual(cap_acquisition_value, cap_acquisition_throttle) + + # validate the throttle condition to be hit atleast once + cap_acquisition_throttle_hit_count = self.perf_dump()['mds_server']['cap_acquisition_throttle'] + self.assertGreaterEqual(cap_acquisition_throttle_hit_count, 1) + + def test_client_release_bug(self): + """ + When a client has a bug (which we will simulate) preventing it from releasing caps, + the MDS should notice that releases are not being sent promptly, and generate a health + metric to that effect. + """ + + # The debug hook to inject the failure only exists in the fuse client + if not isinstance(self.mount_a, FuseMount): + raise SkipTest("Require FUSE client to inject client release failure") + + self.set_conf('client.{0}'.format(self.mount_a.client_id), 'client inject release failure', 'true') + self.mount_a.teardown() + self.mount_a.mount() + self.mount_a.wait_until_mounted() + mount_a_client_id = self.mount_a.get_global_id() + + # Client A creates a file. He will hold the write caps on the file, and later (simulated bug) fail + # to comply with the MDSs request to release that cap + self.mount_a.run_shell(["touch", "file1"]) + + # Client B tries to stat the file that client A created + rproc = self.mount_b.write_background("file1") + + # After session_timeout, we should see a health warning (extra lag from + # MDS beacon period) + session_timeout = self.fs.get_var("session_timeout") + self.wait_for_health("MDS_CLIENT_LATE_RELEASE", session_timeout + 10) + + # Client B should still be stuck + self.assertFalse(rproc.finished) + + # Kill client A + self.mount_a.kill() + self.mount_a.kill_cleanup() + + # Client B should complete + self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id]) + rproc.wait() + + def test_client_oldest_tid(self): + """ + When a client does not advance its oldest tid, the MDS should notice that + and generate health warnings. + """ + + # num of requests client issues + max_requests = 1000 + + # The debug hook to inject the failure only exists in the fuse client + if not isinstance(self.mount_a, FuseMount): + raise SkipTest("Require FUSE client to inject client release failure") + + self.set_conf('client', 'client inject fixed oldest tid', 'true') + self.mount_a.teardown() + self.mount_a.mount() + self.mount_a.wait_until_mounted() + + self.fs.mds_asok(['config', 'set', 'mds_max_completed_requests', '{0}'.format(max_requests)]) + + # Create lots of files + self.mount_a.create_n_files("testdir/file1", max_requests + 100) + + # Create a few files synchronously. This makes sure previous requests are completed + self.mount_a.create_n_files("testdir/file2", 5, True) + + # Wait for the health warnings. Assume mds can handle 10 request per second at least + self.wait_for_health("MDS_CLIENT_OLDEST_TID", max_requests // 10) + + def _test_client_cache_size(self, mount_subdir): + """ + check if client invalidate kernel dcache according to its cache size config + """ + + # The debug hook to inject the failure only exists in the fuse client + if not isinstance(self.mount_a, FuseMount): + raise SkipTest("Require FUSE client to inject client release failure") + + if mount_subdir: + # fuse assigns a fix inode number (1) to root inode. But in mounting into + # subdir case, the actual inode number of root is not 1. This mismatch + # confuses fuse_lowlevel_notify_inval_entry() when invalidating dentries + # in root directory. + self.mount_a.run_shell(["mkdir", "subdir"]) + self.mount_a.umount_wait() + self.set_conf('client', 'client mountpoint', '/subdir') + self.mount_a.mount() + self.mount_a.wait_until_mounted() + root_ino = self.mount_a.path_to_ino(".") + self.assertEqual(root_ino, 1); + + dir_path = os.path.join(self.mount_a.mountpoint, "testdir") + + mkdir_script = dedent(""" + import os + os.mkdir("{path}") + for n in range(0, {num_dirs}): + os.mkdir("{path}/dir{{0}}".format(n)) + """) + + num_dirs = 1000 + self.mount_a.run_python(mkdir_script.format(path=dir_path, num_dirs=num_dirs)) + self.mount_a.run_shell(["sync"]) + + dentry_count, dentry_pinned_count = self.mount_a.get_dentry_count() + self.assertGreaterEqual(dentry_count, num_dirs) + self.assertGreaterEqual(dentry_pinned_count, num_dirs) + + cache_size = num_dirs // 10 + self.mount_a.set_cache_size(cache_size) + + def trimmed(): + dentry_count, dentry_pinned_count = self.mount_a.get_dentry_count() + log.info("waiting, dentry_count, dentry_pinned_count: {0}, {1}".format( + dentry_count, dentry_pinned_count + )) + if dentry_count > cache_size or dentry_pinned_count > cache_size: + return False + + return True + + self.wait_until_true(trimmed, 30) + + @needs_trimming + def test_client_cache_size(self): + self._test_client_cache_size(False) + self._test_client_cache_size(True) + + def test_client_max_caps(self): + """ + That the MDS will not let a client sit above mds_max_caps_per_client caps. + """ + + mds_min_caps_per_client = int(self.config_get('mds.a', "mds_min_caps_per_client")) + mds_max_caps_per_client = 2*mds_min_caps_per_client + self.config_set('mds', 'mds_max_caps_per_client', mds_max_caps_per_client) + + self.mount_a.create_n_files("foo/", 3*mds_max_caps_per_client, sync=True) + + mount_a_client_id = self.mount_a.get_global_id() + def expected_caps(): + num_caps = self.get_session(mount_a_client_id)['num_caps'] + if num_caps <= mds_max_caps_per_client: + return True + else: + return False + + self.wait_until_true(expected_caps, timeout=60) |