""" Exercise the MDS's behaviour when clients and the MDCache reach or exceed the limits of how many caps/inodes they should hold. """ import contextlib import logging from unittest import SkipTest from teuthology.orchestra.run import CommandFailedError from tasks.cephfs.filesystem import Filesystem from tasks.cephfs.fuse_mount import FuseMount from tasks.cephfs.cephfs_test_case import CephFSTestCase, run_tests 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): # Environment references mds_session_timeout = None mds_reconnect_timeout = None ms_max_backoff = None def wait_for_health(self, pattern, timeout): """ Wait until 'ceph health' contains a single message matching the pattern """ def seen_health_warning(): health = self.fs.mon_manager.get_mon_health() summary_strings = [s['summary'] for s in health['summary']] if len(summary_strings) == 0: log.debug("Not expected number of summary strings ({0})".format(summary_strings)) return False elif len(summary_strings) == 1 and pattern in summary_strings[0]: return True else: raise RuntimeError("Unexpected health messages: {0}".format(summary_strings)) self.wait_until_true(seen_health_warning, timeout) def _test_client_pin(self, use_subdir): """ 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 """ cache_size = 200 open_files = 250 self.set_conf('mds', 'mds cache size', cache_size) self.fs.mds_restart() self.fs.wait_for_daemons() mount_a_client_id = self.mount_a.get_global_id() path = "subdir/mount_a" if use_subdir else "mount_a" 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 mds_recall_state_timeout = int(self.fs.get_config("mds_recall_state_timeout")) self.wait_for_health("failing to respond to cache pressure", mds_recall_state_timeout + 10) # 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 cache size and overall ratio self.wait_until_equal( lambda: self.get_session(mount_a_client_id)['num_caps'], int(cache_size * 0.8), timeout=600, reject_fn=lambda x: x < int(cache_size*.8)) def test_client_pin_root(self): self._test_client_pin(False) def test_client_pin(self): self._test_client_pin(True) 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 mds_revoke_cap_timeout, we should see a health warning (extra lag from # MDS beacon period) mds_revoke_cap_timeout = int(self.fs.get_config("mds_revoke_cap_timeout")) self.wait_for_health("failing to respond to capability release", mds_revoke_cap_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() @contextlib.contextmanager def task(ctx, config): fs = Filesystem(ctx) # Pick out the clients we will use from the configuration # ======================================================= if len(ctx.mounts) < 2: raise RuntimeError("Need at least two clients") mount_a = ctx.mounts.values()[0] mount_b = ctx.mounts.values()[1] if not isinstance(mount_a, FuseMount) or not isinstance(mount_b, FuseMount): # kclient kill() power cycles nodes, so requires clients to each be on # their own node if mount_a.client_remote.hostname == mount_b.client_remote.hostname: raise RuntimeError("kclient clients must be on separate nodes") # Stash references on ctx so that we can easily debug in interactive mode # ======================================================================= ctx.filesystem = fs ctx.mount_a = mount_a ctx.mount_b = mount_b run_tests(ctx, config, TestClientLimits, { 'fs': fs, 'mount_a': mount_a, 'mount_b': mount_b }) # Continue to any downstream tasks # ================================ yield