Synnefo » snf-ganeti

#!/usr/bin/python

#

# Copyright (C) 2006, 2007, 2010 Google Inc.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""Run an executable on a list of hosts.

Script to serially run an executable on a list of hosts via ssh

with password auth as root. If the provided log dir does not yet

exist, it will try to create it.

Implementation:

 - the main process spawns up to batch_size children, which:

 - connects to the remote host via ssh as root

 - uploads the executable with a random name to /tmp via sftp

 - chmod 500s it

 - via ssh: chdirs into the upload directory and runs the script

 - deletes it

 - writes status messages and all output to one logfile per host

 - the main process gathers then the status of the children and

   reports the success/failure ratio

 - entire script can be aborted with Ctrl-C

Security considerations:

 - the root password for the remote hosts is stored in memory for the

   runtime of the script

 - the executable to be run on the remote host is handled the following way:

   - try to create a random directory with permissions 700 on the

     remote host, abort furter processing on this host if this failes

   - upload the executable with to a random filename in that directory

   - set executable permissions to 500

   - run the executable

   - delete the execuable and the directory on the remote host

"""

# pylint: disable-msg=C0103

# C0103: Invalid name ganeti-listrunner

import errno

import getopt

import getpass

import logging

import os

import random

import select

import socket

import sys

import time

import traceback

import paramiko

REMOTE_PATH_BASE = "/tmp/listrunner"

def LogDirUseable(logdir):

  """Ensure log file directory is available and usable."""

  testfile = "%s/test-%s-%s.deleteme" % (logdir, random.random(),

                                         random.random())

  try:

    os.mkdir(logdir)

  except OSError, err:

    if err.errno != errno.EEXIST:

      raise

  try:

    logtest = open(testfile, "aw")

    logtest.writelines("log file writeability test\n")

    logtest.close()

    os.unlink(testfile)

    return True

  except (OSError, IOError):

    return False

def ShowHelp(executable):

  """Print short usage information."""

  print ("usage: %s -l logdir [-c|-x] value [-b batch_size]"

         " [-f hostfile|-h hosts] [-u username]"

         " [-p password_file]" % executable)

  print """        -l logdir to write logfiles to

        -x executable to run on remote host(s)

        -c shell command to run on remote host(s)

        -f hostlist file (one host per line)

        -a optional auxiliary file to upload (can be given multiple times)

        -b batch-size, how many hosts to process in parallel [15]

        -h comma-separated list of hosts or single hostname

        -u username used to connect [root]

        -p password used to authenticate"""

def GetTimeStamp(timestamp=None):

  """Return ISO8601 timestamp.

  Returns ISO8601 timestamp, optionally expects a time.localtime() tuple

  in timestamp, but will use the current time if this argument is not

  supplied.

  """

  if timestamp is None:

    timestamp = time.localtime()

  isotime = time.strftime("%Y-%m-%dT%H:%M:%S", timestamp)

  return isotime

def PingByTcp(target, port, timeout=10, live_port_needed=False, source=None):

  """Simple ping implementation using TCP connect(2).

  Try to do a TCP connect(2) from an optional source IP to the

  specified target IP and the specified target port. If the optional

  parameter live_port_needed is set to true, requires the remote end

  to accept the connection. The timeout is specified in seconds and

  defaults to 10 seconds. If the source optional argument is not

  passed, the source address selection is left to the kernel,

  otherwise we try to connect using the passed address (failures to

  bind other than EADDRNOTAVAIL will be ignored).

  """

  sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

  success = False

  if source is not None:

    try:

      sock.bind((source, 0))

    except socket.error, (errcode):

      if errcode == errno.EADDRNOTAVAIL:

        success = False

  sock.settimeout(timeout)

  try:

    sock.connect((target, port))

    sock.close()

    success = True

  except socket.timeout:

    success = False

  except socket.error, (errcode):

    success = (not live_port_needed) and (errcode == errno.ECONNREFUSED)

  return success

def GetHosts(hostsfile):

  """Return list of hosts from hostfile.

  Reads the hostslist file and returns a list of hosts.

  Expects the hostslist file to contain one hostname per line.

  """

  try:

    datafile = open(hostsfile, "r")

  except IOError, msg:

    print "Failed to open hosts file %s: %s" % (hostsfile, msg)

    sys.exit(2)

  hosts = datafile.readlines()

  datafile.close()

  return hosts

def WriteLog(message, logfile):

  """Writes message, terminated by newline, to logfile."""

  try:

    logfile = open(logfile, "aw")

  except IOError, msg:

    print "failed to open log file %s: %s" % (logfile, msg)

    print "log message was: %s" % message

    sys.exit(1)  # no being able to log is critical

  try:

    timestamp = GetTimeStamp()

    logfile.writelines("%s %s\n" % (timestamp, message))

    logfile.close()

  except IOError, msg:

    print "failed to write to logfile %s: %s" % (logfile, msg)

    print "log message was: %s" % message

    sys.exit(1)  # no being able to log is critical

def GetAgentKeys():

  """Tries to get a list of ssh keys from an agent."""

  try:

    agent = paramiko.Agent()

    return list(agent.get_keys())

  except paramiko.SSHException:

    return []

def SetupSshConnection(host, username, password, keys, logfile):

  """Setup the ssh connection used for all later steps.

  This function sets up the ssh connection that will be used both

  for upload and remote command execution.

  On success, it will return paramiko.Transport object with an

  already logged in session. On failure, False will be returned.

  """

  # check if target is willing to talk to us at all

  if not PingByTcp(host, 22, live_port_needed=True):

    WriteLog("ERROR: FAILURE_NOT_REACHABLE", logfile)

    print "  - ERROR: host not reachable on 22/tcp"

    return False

  all_kwargs = [{"pkey": k} for k in keys]

  all_desc = ["key %d" % d for d in range(len(keys))]

  if password is not None:

    all_kwargs.append({"password": password})

    all_desc.append("password")

  # deal with logging out of paramiko.transport

  handler = None

  for desc, kwargs in zip(all_desc, all_kwargs):

    try:

      transport = paramiko.Transport((host, 22))

      # only try to setup the logging handler once

      if not handler:

        handler = logging.StreamHandler()

        handler.setLevel(logging.ERROR)

        log = logging.getLogger(transport.get_log_channel())

        log.addHandler(handler)

      transport.connect(username=username, **kwargs) # pylint: disable-msg=W0142

      WriteLog("ssh connection established using %s" % desc, logfile)

      # strange ... when establishing the session and the immediately

      # setting up the channels for sftp & shell from that, it sometimes

      # fails, but waiting 1 second after session setup makes it always work

      # time.sleep(1)

      # FIXME apparently needfull to give sshd some time

      return transport

    except (socket.gaierror, socket.error, paramiko.SSHException):

      continue

  methods = ", ".join(all_desc)

  WriteLog("ERROR: FAILURE_CONNECTION_SETUP (tried %s) " % methods, logfile)

  WriteLog("aborted", logfile)

  print "  - ERROR: connection setup failed (tried %s)" % methods

  return False

def UploadFiles(connection, executable, filelist, logfile):

  """Uploads the specified files via sftp.

  Uploads the specified files to a random, freshly created directory with

  a temporary name under /tmp. All uploaded files are chmod 0400 after upload

  with the exception of executable, with is chmod 500.

  Upon success, returns the absolute path to the remote upload directory,

  but will return False upon failure.

  """

  remote_dir = "%s.%s-%s" % (REMOTE_PATH_BASE,

                             random.random(), random.random())

  try:

    sftp = paramiko.SFTPClient.from_transport(connection)

    sftp.mkdir(remote_dir, mode=0700)

    for item in filelist:

      remote_file = "%s/%s" % (remote_dir, item.split("/").pop())

      WriteLog("uploading %s to remote %s" % (item, remote_file), logfile)

      sftp.put(item, remote_file)

      if item == executable:

        sftp.chmod(remote_file, 0500)

      else:

        sftp.chmod(remote_file, 0400)

    sftp.close()

  except IOError, err:

    WriteLog("ERROR: FAILURE_UPLOAD: %s" % err, logfile)

    return False

  return remote_dir

def CleanupRemoteDir(connection, upload_dir, filelist, logfile):

  """Cleanes out and removes the remote work directory."""

  try:

    sftp = paramiko.SFTPClient.from_transport(connection)

    for item in filelist:

      fullpath = "%s/%s" % (upload_dir, item.split("/").pop())

      WriteLog("removing remote %s" % fullpath, logfile)

      sftp.remove(fullpath)

    sftp.rmdir(upload_dir)

    sftp.close()

  except IOError, err:

    WriteLog("ERROR: FAILURE_CLEANUP: %s" % err, logfile)

    return False

  return True

def RunRemoteCommand(connection, command, logfile):

  """Execute the command via ssh on the remote host."""

  session = connection.open_session()

  session.setblocking(0)

  # the following dance is needed because paramiko changed APIs:

  # from returning True/False for success to always returning None

  # and throwing an exception in case of problems.

  # And I want to support both the old and the new API.

  result = True  # being optimistic here, I know

  message = None

  try:

    if session.exec_command("%s 2>&1" % command) is False:

      result = False

  except paramiko.SSHException, message:

    result = False

  if not result:

    WriteLog("ERROR: FAILURE_COMMAND_EXECUTION: %s" % message, logfile)

    return False

   ### Read when data is available

  output = ""

  while select.select([session], [], []):

    data = session.recv(1024)

    if not data:

      break

    output += data

    select.select([], [], [], .1)

  WriteLog("SUCCESS: command output follows", logfile)

  for line in output.split("\n"):

    WriteLog("output = %s" %line, logfile)

  WriteLog("command execution completed", logfile)

  session.close()

  return True

def HostWorker(logdir, username, password, keys, hostname,

               executable, command, filelist):

  """Per-host worker.

  This function does not return - it's the main code of the childs,

  which exit at the end of this function. The exit code 0 or 1 will be

  interpreted by the parent.

  Args:

    logdir: the directory where the logfiles must be created

    username: SSH username

    password: SSH password

    keys: SSH keys

    hostname: the hostname to connect to

    executable: the executable to upload, if not None

    command: the command to run

    filelist: auxiliary files to upload

  """

  # in the child/worker process

  logfile = "%s/%s.log" % (logdir, hostname)

  print "%s - starting" % hostname

  result = 0  # optimism, I know

  try:

    connection = SetupSshConnection(hostname, username,

                                    password, keys, logfile)

    if connection is not False:

      if executable is not None:

        print "  %s: uploading files" % hostname

        upload_dir = UploadFiles(connection, executable,

                                 filelist, logfile)

        command = "cd %s && ./%s" % (upload_dir,

                                     executable.split("/").pop())

      print "  %s: executing remote command" % hostname

      cmd_result = RunRemoteCommand(connection, command, logfile)

      if cmd_result is True:

        print "  %s: remote command execution successful" % hostname

      else:

        print ("  %s: remote command execution failed,"

               " check log for details" % hostname)

        result = 1

      if executable is not None:

        print "  %s: cleaning up remote work dir" % hostname

        cln_result = CleanupRemoteDir(connection, upload_dir,

                                      filelist, logfile)

        if cln_result is False:

          print ("  %s: remote work dir cleanup failed, check"

                 " log for details" % hostname)

          result = 1

      connection.close()

    else:

      print "  %s: connection setup failed, skipping" % hostname

      result = 1

  except KeyboardInterrupt:

    print "  %s: received KeyboardInterrupt, aborting" % hostname

    WriteLog("ERROR: ABORT_KEYBOARD_INTERRUPT", logfile)

    result = 1

  except Exception, err:

    result = 1

    trace = traceback.format_exc()

    msg = "ERROR: UNHANDLED_EXECPTION_ERROR: %s\nTrace: %s" % (err, trace)

    WriteLog(msg, logfile)

    print "  %s: %s" % (hostname, msg)

  # and exit with exit code 0 or 1, so the parent can compute statistics

  sys.exit(result)

def LaunchWorker(child_pids, logdir, username, password, keys, hostname,

                 executable, command, filelist):

  """Launch the per-host worker.

  Arguments are the same as for HostWorker, except for child_pids,

  which is a dictionary holding the pid-to-hostname mapping.

  """

  hostname = hostname.rstrip("\n")

  pid = os.fork()

  if pid > 0:

    # controller just record the pids

    child_pids[pid] = hostname

  else:

    HostWorker(logdir, username, password, keys, hostname,

               executable, command, filelist)

def main():

  """main."""

  try:

    optlist, _ = getopt.getopt(sys.argv[1:], "l:x:h:f:a:c:b:u:p:A")

  except getopt.GetoptError, err:

    print str(err)

    ShowHelp(sys.argv[0])

    sys.exit(2)

  logdir = executable = hostfile = hostlist = command = None

  use_agent = False

  auxfiles = []

  username = "root"

  password = None

  batch_size = 15

  for option in optlist:

    if option[0] == "-l":

      logdir = option[1]

    if option[0] == "-x":

      executable = option[1]

    if option[0] == "-f":

      hostfile = option[1]

    if option[0] == "-h":

      hostlist = option[1]

    if option[0] == "-a":

      auxfiles.append(option[1])

    if option[0] == "-c":

      command = option[1]

    if option[0] == "-b":

      batch_size = int(option[1])

    if option[0] == "-u":

      username = option[1]

    if option[0] == "-p":

      password = option[1]

    if option[0] == "-A":

      use_agent = True

  if not (logdir and (executable or command) and (hostfile or hostlist)):

    print "error: missing required commandline argument(s)"

    ShowHelp(sys.argv[0])

    sys.exit(3)

  if executable and command:

    print "error: can run either a command or an executable, not both"

    ShowHelp(sys.argv[0])

    sys.exit(3)

  if hostlist and hostfile:

    print "error: specify either -f or -h arguments, not both"

    ShowHelp(sys.argv[0])

    sys.exit(3)

  ### Unbuffered sys.stdout

  sys.stdout = os.fdopen(1, "w", 0)

  if LogDirUseable(logdir) is False:

    print "ERROR: cannot create logfiles in dir %s, aborting" % logdir

    sys.exit(1)

  keys = []

  if use_agent:

    keys = GetAgentKeys()

  elif password:

    try:

      fh = file(password)

      pwvalue = fh.readline().strip()

      fh.close()

    except IOError, e:

      print "error: can not read in from password file %s: %s" % (password, e)

      sys.exit(1)

    password = pwvalue

  else:

    password = getpass.getpass("%s's password for all nodes: " % username)

  if hostfile:

    hosts = GetHosts(hostfile)

  else:

    if "," in hostlist:

      hostlist = hostlist.rstrip(",")  # commandline robustness

      hosts = hostlist.split(",")

    else:

      hosts = [hostlist]

  successes = failures = 0

  filelist = auxfiles[:]

  filelist.append(executable)

  # initial batch

  batch = hosts[:batch_size]

  hosts = hosts[batch_size:]

  child_pids = {}

  for hostname in batch:

    LaunchWorker(child_pids, logdir, username, password, keys, hostname,

                 executable, command, filelist)

  while child_pids:

    pid, status = os.wait()

    hostname = child_pids.pop(pid, "<unknown host>")

    print "  %s: done (in parent)" % hostname

    if os.WIFEXITED(status) and os.WEXITSTATUS(status) == 0:

      successes += 1

    else:

      failures += 1

    if hosts:

      LaunchWorker(child_pids, logdir, username, password, keys,

                   hosts.pop(0), executable, command, filelist)

  print

  print "All done, %s successful and %s failed hosts" % (successes, failures)

  sys.exit(0)

if __name__ == "__main__":

  try:

    main()

  except KeyboardInterrupt:

    print "Received KeyboardInterrupt, aborting"

    sys.exit(1)