From: Nirmal Ranganathan Date: Fri, 2 Nov 2012 04:05:35 +0000 (-0500) Subject: Adding a SSH Connection Pool. X-Git-Url: https://review.fuel-infra.org/gitweb?a=commitdiff_plain;h=b864a08b2aa7e7ba953dd4afce2c3042ba963ae7;p=openstack-build%2Fcinder-build.git Adding a SSH Connection Pool. Adds a connection pool using eventlet.pools which works well with greenthreads. Adding new parameters ssh_min_pool_conn and ssh_max_pool_conn. Updating the _run_ssh method in san.py to use the connection pool and cleaning up the existing single connections, also added retries. Fixes bug 1074185 Change-Id: I90dd89ffc025d09fc6ad060c4273508103b85456 --- diff --git a/cinder/tests/test_utils.py b/cinder/tests/test_utils.py index 92be797b8..c1298f1bb 100644 --- a/cinder/tests/test_utils.py +++ b/cinder/tests/test_utils.py @@ -19,6 +19,7 @@ import datetime import hashlib import os import os.path +import paramiko import StringIO import tempfile @@ -667,3 +668,88 @@ class AuditPeriodTest(test.TestCase): day=1, month=6, year=2011)) + + +class FakeSSHClient(object): + + def __init__(self): + self.id = utils.gen_uuid() + self.transport = FakeTransport() + + def set_missing_host_key_policy(self, policy): + pass + + def connect(self, ip, port=22, username=None, password=None, + pkey=None, timeout=10): + pass + + def get_transport(self): + return self.transport + + def close(self): + pass + + def __call__(self, *args, **kwargs): + pass + + +class FakeSock(object): + def settimeout(self, timeout): + pass + + +class FakeTransport(object): + + def __init__(self): + self.active = True + self.sock = FakeSock() + + def set_keepalive(self, timeout): + pass + + def is_active(self): + return self.active + + +class SSHPoolTestCase(test.TestCase): + """Unit test for SSH Connection Pool.""" + + def setup(self): + self.mox.StubOutWithMock(paramiko, "SSHClient") + paramiko.SSHClient().AndReturn(FakeSSHClient()) + self.mox.ReplayAll() + + def test_single_ssh_connect(self): + self.setup() + sshpool = utils.SSHPool("127.0.0.1", 22, 10, "test", password="test", + min_size=1, max_size=1) + with sshpool.item() as ssh: + first_id = ssh.id + + with sshpool.item() as ssh: + second_id = ssh.id + + self.assertEqual(first_id, second_id) + + def test_closed_reopend_ssh_connections(self): + self.setup() + sshpool = utils.SSHPool("127.0.0.1", 22, 10, "test", password="test", + min_size=1, max_size=2) + with sshpool.item() as ssh: + first_id = ssh.id + with sshpool.item() as ssh: + second_id = ssh.id + # Close the connection and test for a new connection + ssh.get_transport().active = False + + self.assertEqual(first_id, second_id) + + # The mox items are not getting setup in a new pool connection, + # so had to reset and set again. + self.mox.UnsetStubs() + self.setup() + + with sshpool.item() as ssh: + third_id = ssh.id + + self.assertNotEqual(first_id, third_id) diff --git a/cinder/utils.py b/cinder/utils.py index 752f11e04..e8035ea58 100644 --- a/cinder/utils.py +++ b/cinder/utils.py @@ -28,6 +28,7 @@ import hashlib import inspect import itertools import os +import paramiko import pyclbr import random import re @@ -46,6 +47,7 @@ from xml.sax import saxutils from eventlet import event from eventlet import greenthread +from eventlet import pools from eventlet.green import subprocess from cinder.common import deprecated @@ -232,7 +234,7 @@ def trycmd(*args, **kwargs): def ssh_execute(ssh, cmd, process_input=None, addl_env=None, check_exit_code=True): - LOG.debug(_('Running cmd (SSH): %s'), ' '.join(cmd)) + LOG.debug(_('Running cmd (SSH): %s'), cmd) if addl_env: raise exception.Error(_('Environment not supported over SSH')) @@ -251,6 +253,8 @@ def ssh_execute(ssh, cmd, process_input=None, stdout = stdout_stream.read() stderr = stderr_stream.read() stdin_stream.close() + stdout_stream.close() + stderr_stream.close() exit_status = channel.recv_exit_status() @@ -261,11 +265,84 @@ def ssh_execute(ssh, cmd, process_input=None, raise exception.ProcessExecutionError(exit_code=exit_status, stdout=stdout, stderr=stderr, - cmd=' '.join(cmd)) - + cmd=cmd) + channel.close() return (stdout, stderr) +class SSHPool(pools.Pool): + """A simple eventlet pool to hold ssh connections.""" + + def __init__(self, ip, port, conn_timeout, login, password=None, + privatekey=None, *args, **kwargs): + self.ip = ip + self.port = port + self.login = login + self.password = password + self.conn_timeout = conn_timeout + self.privatekey = privatekey + super(SSHPool, self).__init__(*args, **kwargs) + + def create(self): + try: + ssh = paramiko.SSHClient() + ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) + if self.password: + ssh.connect(self.ip, + port=self.port, + username=self.login, + password=self.password, + timeout=self.conn_timeout) + elif self.privatekey: + pkfile = os.path.expanduser(self.privatekey) + privatekey = paramiko.RSAKey.from_private_key_file(pkfile) + ssh.connect(self.ip, + port=self.port, + username=self.login, + pkey=privatekey, + timeout=self.conn_timeout) + else: + msg = _("Specify a password or private_key") + raise exception.CinderException(msg) + + # Paramiko by default sets the socket timeout to 0.1 seconds, + # ignoring what we set thru the sshclient. This doesn't help for + # keeping long lived connections. Hence we have to bypass it, by + # overriding it after the transport is initialized. We are setting + # the sockettimeout to None and setting a keepalive packet so that, + # the server will keep the connection open. All that does is send + # a keepalive packet every ssh_conn_timeout seconds. + transport = ssh.get_transport() + transport.sock.settimeout(None) + transport.set_keepalive(self.conn_timeout) + return ssh + except Exception as e: + msg = "Error connecting via ssh: %s" % e + LOG.error(_(msg)) + raise paramiko.SSHException(msg) + + def get(self): + """ + Return an item from the pool, when one is available. This may + cause the calling greenthread to block. Check if a connection is active + before returning it. For dead connections create and return a new + connection. + """ + if self.free_items: + conn = self.free_items.popleft() + if conn: + if conn.get_transport().is_active(): + return conn + else: + conn.close() + return self.create() + if self.current_size < self.max_size: + created = self.create() + self.current_size += 1 + return created + return self.channel.get() + + def cinderdir(): import cinder return os.path.abspath(cinder.__file__).split('cinder/__init__.py')[0] diff --git a/cinder/volume/san/san.py b/cinder/volume/san/san.py index c57eb3a21..feda4fc12 100644 --- a/cinder/volume/san/san.py +++ b/cinder/volume/san/san.py @@ -21,8 +21,10 @@ The unique thing about a SAN is that we don't expect that we can run the volume controller on the SAN hardware. We expect to access it over SSH or some API. """ -import os import paramiko +import random + +from eventlet import greenthread from cinder import exception from cinder import flags @@ -60,6 +62,15 @@ san_opts = [ default=False, help='Execute commands locally instead of over SSH; ' 'use if the volume service is running on the SAN device'), + cfg.IntOpt('ssh_conn_timeout', + default=30, + help="SSH connection timeout in seconds"), + cfg.IntOpt('ssh_min_pool_conn', + default=1, + help='Minimum ssh connections in the pool'), + cfg.IntOpt('ssh_max_pool_conn', + default=5, + help='Maximum ssh connections in the pool'), ] FLAGS = flags.FLAGS @@ -77,32 +88,11 @@ class SanISCSIDriver(ISCSIDriver): def __init__(self, *args, **kwargs): super(SanISCSIDriver, self).__init__(*args, **kwargs) self.run_local = FLAGS.san_is_local + self.sshpool = None def _build_iscsi_target_name(self, volume): return "%s%s" % (FLAGS.iscsi_target_prefix, volume['name']) - def _connect_to_ssh(self): - ssh = paramiko.SSHClient() - #TODO(justinsb): We need a better SSH key policy - ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) - if FLAGS.san_password: - ssh.connect(FLAGS.san_ip, - port=FLAGS.san_ssh_port, - username=FLAGS.san_login, - password=FLAGS.san_password) - elif FLAGS.san_private_key: - privatekeyfile = os.path.expanduser(FLAGS.san_private_key) - # It sucks that paramiko doesn't support DSA keys - privatekey = paramiko.RSAKey.from_private_key_file(privatekeyfile) - ssh.connect(FLAGS.san_ip, - port=FLAGS.san_ssh_port, - username=FLAGS.san_login, - pkey=privatekey) - else: - msg = _("Specify san_password or san_private_key") - raise exception.InvalidInput(reason=msg) - return ssh - def _execute(self, *cmd, **kwargs): if self.run_local: return utils.execute(*cmd, **kwargs) @@ -111,16 +101,33 @@ class SanISCSIDriver(ISCSIDriver): command = ' '.join(cmd) return self._run_ssh(command, check_exit_code) - def _run_ssh(self, command, check_exit_code=True): - #TODO(justinsb): SSH connection caching (?) - ssh = self._connect_to_ssh() - - #TODO(justinsb): Reintroduce the retry hack - ret = utils.ssh_execute(ssh, command, check_exit_code=check_exit_code) - - ssh.close() - - return ret + def _run_ssh(self, command, check_exit_code=True, attempts=1): + if not self.sshpool: + self.sshpool = utils.SSHPool(FLAGS.san_ip, + FLAGS.san_ssh_port, + FLAGS.ssh_conn_timeout, + FLAGS.san_login, + password=FLAGS.san_password, + privatekey=FLAGS.san_private_key, + min_size=FLAGS.ssh_min_pool_conn, + max_size=FLAGS.ssh_max_pool_conn) + try: + total_attempts = attempts + with self.sshpool.item() as ssh: + while attempts > 0: + attempts -= 1 + try: + return utils.ssh_execute(ssh, command, + check_exit_code=check_exit_code) + except Exception as e: + LOG.error(e) + greenthread.sleep(random.randint(20, 500) / 100.0) + raise paramiko.SSHException(_("SSH Command failed after '%r' " + "attempts: '%s'" + % (total_attempts, command))) + except Exception as e: + LOG.error(_("Error running ssh command: %s" % command)) + raise e def ensure_export(self, context, volume): """Synchronously recreates an export for a logical volume.""" diff --git a/etc/cinder/cinder.conf.sample b/etc/cinder/cinder.conf.sample index 93137047f..f976d05ea 100644 --- a/etc/cinder/cinder.conf.sample +++ b/etc/cinder/cinder.conf.sample @@ -711,6 +711,15 @@ #### (BoolOpt) Execute commands locally instead of over SSH; use if the #### volume service is running on the SAN device +# ssh_conn_timeout=30 +#### (IntOpt) SSH connection timeout in seconds + +# ssh_min_pool_conn=1 +#### (IntOpt) Minimum ssh connections in the pool + +# ssh_max_pool_conn=5 +#### (IntOpt) Maximum ssh connections in the pool + ######## defined in cinder.volume.solaris ########