Add generic retry loop function
[ganeti-local] / lib / bootstrap.py
index d28135a..b7a677f 100644 (file)
 
 import os
 import os.path
-import sha
 import re
 import logging
+import tempfile
+import time
 
 from ganeti import rpc
 from ganeti import ssh
@@ -37,17 +38,16 @@ from ganeti import config
 from ganeti import constants
 from ganeti import objects
 from ganeti import ssconf
+from ganeti import serializer
+from ganeti import hypervisor
 
-def _InitSSHSetup(node):
-  """Setup the SSH configuration for the cluster.
 
+def _InitSSHSetup():
+  """Setup the SSH configuration for the cluster.
 
   This generates a dsa keypair for root, adds the pub key to the
   permitted hosts and adds the hostkey to its own known hosts.
 
-  Args:
-    node: the name of this host as a fqdn
-
   """
   priv_key, pub_key, auth_keys = ssh.GetUserFiles(constants.GANETI_RUNAS)
 
@@ -63,30 +63,68 @@ def _InitSSHSetup(node):
     raise errors.OpExecError("Could not generate ssh keypair, error %s" %
                              result.output)
 
-  f = open(pub_key, 'r')
+  utils.AddAuthorizedKey(auth_keys, utils.ReadFile(pub_key))
+
+
+def GenerateSelfSignedSslCert(file_name, validity=(365 * 5)):
+  """Generates a self-signed SSL certificate.
+
+  @type file_name: str
+  @param file_name: Path to output file
+  @type validity: int
+  @param validity: Validity for certificate in days
+
+  """
+  (fd, tmp_file_name) = tempfile.mkstemp(dir=os.path.dirname(file_name))
   try:
-    utils.AddAuthorizedKey(auth_keys, f.read(8192))
+    try:
+      # Set permissions before writing key
+      os.chmod(tmp_file_name, 0600)
+
+      result = utils.RunCmd(["openssl", "req", "-new", "-newkey", "rsa:1024",
+                             "-days", str(validity), "-nodes", "-x509",
+                             "-keyout", tmp_file_name, "-out", tmp_file_name,
+                             "-batch"])
+      if result.failed:
+        raise errors.OpExecError("Could not generate SSL certificate, command"
+                                 " %s had exitcode %s and error message %s" %
+                                 (result.cmd, result.exit_code, result.output))
+
+      # Make read-only
+      os.chmod(tmp_file_name, 0400)
+
+      os.rename(tmp_file_name, file_name)
+    finally:
+      utils.RemoveFile(tmp_file_name)
   finally:
-    f.close()
+    os.close(fd)
+
+
+def GenerateHmacKey(file_name):
+  """Writes a new HMAC key.
+
+  @type file_name: str
+  @param file_name: Path to output file
+
+  """
+  utils.WriteFile(file_name, data=utils.GenerateSecret(), mode=0400)
 
 
-def _InitGanetiServerSetup():
+def _InitGanetiServerSetup(master_name):
   """Setup the necessary configuration for the initial node daemon.
 
   This creates the nodepass file containing the shared password for
   the cluster and also generates the SSL certificate.
 
   """
-  result = utils.RunCmd(["openssl", "req", "-new", "-newkey", "rsa:1024",
-                         "-days", str(365*5), "-nodes", "-x509",
-                         "-keyout", constants.SSL_CERT_FILE,
-                         "-out", constants.SSL_CERT_FILE, "-batch"])
-  if result.failed:
-    raise errors.OpExecError("could not generate server ssl cert, command"
-                             " %s had exitcode %s and error message %s" %
-                             (result.cmd, result.exit_code, result.output))
+  GenerateSelfSignedSslCert(constants.SSL_CERT_FILE)
+
+  # Don't overwrite existing file
+  if not os.path.exists(constants.RAPI_CERT_FILE):
+    GenerateSelfSignedSslCert(constants.RAPI_CERT_FILE)
 
-  os.chmod(constants.SSL_CERT_FILE, 0400)
+  if not os.path.exists(constants.HMAC_CLUSTER_KEY):
+    GenerateHmacKey(constants.HMAC_CLUSTER_KEY)
 
   result = utils.RunCmd([constants.NODE_INITD_SCRIPT, "restart"])
 
@@ -95,45 +133,75 @@ def _InitGanetiServerSetup():
                              " had exitcode %s and error %s" %
                              (result.cmd, result.exit_code, result.output))
 
+  # Wait for node daemon to become responsive
+  end_time = time.time() + 10.0
+  while True:
+    result = rpc.RpcRunner.call_version([master_name])[master_name]
+    if not result.fail_msg:
+      break
+
+    if time.time() > end_time:
+      raise errors.OpExecError("Node daemon didn't answer queries within"
+                               " 10 seconds")
 
-def InitCluster(cluster_name, mac_prefix, def_bridge,
-                master_netdev, file_storage_dir,
-                secondary_ip=None,
-                vg_name=None, beparams=None, hvparams=None,
-                enabled_hypervisors=None, default_hypervisor=None):
+    time.sleep(1)
+
+
+def InitCluster(cluster_name, mac_prefix,
+                master_netdev, file_storage_dir, candidate_pool_size,
+                secondary_ip=None, vg_name=None, beparams=None,
+                nicparams=None, hvparams=None, enabled_hypervisors=None,
+                modify_etc_hosts=True, modify_ssh_setup=True):
   """Initialise the cluster.
 
+  @type candidate_pool_size: int
+  @param candidate_pool_size: master candidate pool size
+
   """
+  # TODO: complete the docstring
   if config.ConfigWriter.IsCluster():
-    raise errors.OpPrereqError("Cluster is already initialised")
+    raise errors.OpPrereqError("Cluster is already initialised",
+                               errors.ECODE_STATE)
+
+  if not enabled_hypervisors:
+    raise errors.OpPrereqError("Enabled hypervisors list must contain at"
+                               " least one member", errors.ECODE_INVAL)
+  invalid_hvs = set(enabled_hypervisors) - constants.HYPER_TYPES
+  if invalid_hvs:
+    raise errors.OpPrereqError("Enabled hypervisors contains invalid"
+                               " entries: %s" % invalid_hvs,
+                               errors.ECODE_INVAL)
 
   hostname = utils.HostInfo()
 
   if hostname.ip.startswith("127."):
     raise errors.OpPrereqError("This host's IP resolves to the private"
                                " range (%s). Please fix DNS or %s." %
-                               (hostname.ip, constants.ETC_HOSTS))
+                               (hostname.ip, constants.ETC_HOSTS),
+                               errors.ECODE_ENVIRON)
 
   if not utils.OwnIpAddress(hostname.ip):
     raise errors.OpPrereqError("Inconsistency: this host's name resolves"
                                " to %s,\nbut this ip address does not"
-                               " belong to this host."
-                               " Aborting." % hostname.ip)
+                               " belong to this host. Aborting." %
+                               hostname.ip, errors.ECODE_ENVIRON)
 
   clustername = utils.HostInfo(cluster_name)
 
   if utils.TcpPing(clustername.ip, constants.DEFAULT_NODED_PORT,
                    timeout=5):
-    raise errors.OpPrereqError("Cluster IP already active. Aborting.")
+    raise errors.OpPrereqError("Cluster IP already active. Aborting.",
+                               errors.ECODE_NOTUNIQUE)
 
   if secondary_ip:
     if not utils.IsValidIP(secondary_ip):
-      raise errors.OpPrereqError("Invalid secondary ip given")
+      raise errors.OpPrereqError("Invalid secondary ip given",
+                                 errors.ECODE_INVAL)
     if (secondary_ip != hostname.ip and
         not utils.OwnIpAddress(secondary_ip)):
       raise errors.OpPrereqError("You gave %s as secondary IP,"
                                  " but it does not belong to this host." %
-                                 secondary_ip)
+                                 secondary_ip, errors.ECODE_ENVIRON)
   else:
     secondary_ip = hostname.ip
 
@@ -143,53 +211,71 @@ def InitCluster(cluster_name, mac_prefix, def_bridge,
                                           constants.MIN_VG_SIZE)
     if vgstatus:
       raise errors.OpPrereqError("Error: %s\nspecify --no-lvm-storage if"
-                                 " you are not using lvm" % vgstatus)
+                                 " you are not using lvm" % vgstatus,
+                                 errors.ECODE_INVAL)
 
   file_storage_dir = os.path.normpath(file_storage_dir)
 
   if not os.path.isabs(file_storage_dir):
     raise errors.OpPrereqError("The file storage directory you passed is"
-                               " not an absolute path.")
+                               " not an absolute path.", errors.ECODE_INVAL)
 
   if not os.path.exists(file_storage_dir):
     try:
       os.makedirs(file_storage_dir, 0750)
     except OSError, err:
       raise errors.OpPrereqError("Cannot create file storage directory"
-                                 " '%s': %s" %
-                                 (file_storage_dir, err))
+                                 " '%s': %s" % (file_storage_dir, err),
+                                 errors.ECODE_ENVIRON)
 
   if not os.path.isdir(file_storage_dir):
     raise errors.OpPrereqError("The file storage directory '%s' is not"
-                               " a directory." % file_storage_dir)
+                               " a directory." % file_storage_dir,
+                               errors.ECODE_ENVIRON)
 
   if not re.match("^[0-9a-z]{2}:[0-9a-z]{2}:[0-9a-z]{2}$", mac_prefix):
-    raise errors.OpPrereqError("Invalid mac prefix given '%s'" % mac_prefix)
+    raise errors.OpPrereqError("Invalid mac prefix given '%s'" % mac_prefix,
+                               errors.ECODE_INVAL)
 
   result = utils.RunCmd(["ip", "link", "show", "dev", master_netdev])
   if result.failed:
     raise errors.OpPrereqError("Invalid master netdev given (%s): '%s'" %
                                (master_netdev,
-                                result.output.strip()))
+                                result.output.strip()), errors.ECODE_INVAL)
 
   if not (os.path.isfile(constants.NODE_INITD_SCRIPT) and
           os.access(constants.NODE_INITD_SCRIPT, os.X_OK)):
     raise errors.OpPrereqError("Init.d script '%s' missing or not"
-                               " executable." % constants.NODE_INITD_SCRIPT)
+                               " executable." % constants.NODE_INITD_SCRIPT,
+                               errors.ECODE_ENVIRON)
+
+  dirs = [(constants.RUN_GANETI_DIR, constants.RUN_DIRS_MODE)]
+  utils.EnsureDirs(dirs)
+
+  utils.ForceDictType(beparams, constants.BES_PARAMETER_TYPES)
+  utils.ForceDictType(nicparams, constants.NICS_PARAMETER_TYPES)
+  objects.NIC.CheckParameterSyntax(nicparams)
+
+  # hvparams is a mapping of hypervisor->hvparams dict
+  for hv_name, hv_params in hvparams.iteritems():
+    utils.ForceDictType(hv_params, constants.HVS_PARAMETER_TYPES)
+    hv_class = hypervisor.GetHypervisor(hv_name)
+    hv_class.CheckParameterSyntax(hv_params)
 
   # set up the inter-node password and certificate
-  _InitGanetiServerSetup()
+  _InitGanetiServerSetup(hostname.name)
 
   # set up ssh config and /etc/hosts
-  f = open(constants.SSH_HOST_RSA_PUB, 'r')
-  try:
-    sshline = f.read()
-  finally:
-    f.close()
+  sshline = utils.ReadFile(constants.SSH_HOST_RSA_PUB)
   sshkey = sshline.split(" ")[1]
 
-  utils.AddHostToEtcHosts(hostname.name)
-  _InitSSHSetup(hostname.name)
+  if modify_etc_hosts:
+    utils.AddHostToEtcHosts(hostname.name)
+
+  if modify_ssh_setup:
+    _InitSSHSetup()
+
+  now = time.time()
 
   # init of cluster config file
   cluster_config = objects.Cluster(
@@ -198,7 +284,6 @@ def InitCluster(cluster_name, mac_prefix, def_bridge,
     highest_used_port=(constants.FIRST_DRBD_PORT - 1),
     mac_prefix=mac_prefix,
     volume_group_name=vg_name,
-    default_bridge=def_bridge,
     tcpudp_port_pool=set(),
     master_node=hostname.name,
     master_ip=clustername.ip,
@@ -206,21 +291,32 @@ def InitCluster(cluster_name, mac_prefix, def_bridge,
     cluster_name=clustername.name,
     file_storage_dir=file_storage_dir,
     enabled_hypervisors=enabled_hypervisors,
-    default_hypervisor=default_hypervisor,
-    beparams={constants.BEGR_DEFAULT: beparams},
+    beparams={constants.PP_DEFAULT: beparams},
+    nicparams={constants.PP_DEFAULT: nicparams},
     hvparams=hvparams,
+    candidate_pool_size=candidate_pool_size,
+    modify_etc_hosts=modify_etc_hosts,
+    modify_ssh_setup=modify_ssh_setup,
+    ctime=now,
+    mtime=now,
+    uuid=utils.NewUUID(),
     )
   master_node_config = objects.Node(name=hostname.name,
                                     primary_ip=hostname.ip,
-                                    secondary_ip=secondary_ip)
-
-  cfg = InitConfig(constants.CONFIG_VERSION,
-                   cluster_config, master_node_config)
+                                    secondary_ip=secondary_ip,
+                                    serial_no=1,
+                                    master_candidate=True,
+                                    offline=False, drained=False,
+                                    )
+  InitConfig(constants.CONFIG_VERSION, cluster_config, master_node_config)
+  cfg = config.ConfigWriter()
   ssh.WriteKnownHostsFile(cfg, constants.SSH_KNOWN_HOSTS_FILE)
+  cfg.Update(cfg.GetClusterInfo(), logging.error)
 
   # start the master ip
   # TODO: Review rpc call from bootstrap
-  rpc.RpcRunner.call_node_start_master(hostname.name, True)
+  # TODO: Warn on failed start master
+  rpc.RpcRunner.call_node_start_master(hostname.name, True, False)
 
 
 def InitConfig(version, cluster_config, master_node_config,
@@ -231,31 +327,29 @@ def InitConfig(version, cluster_config, master_node_config,
   node, and no instances.
 
   @type version: int
-  @param version: Configuration version
-  @type cluster_config: objects.Cluster
-  @param cluster_config: Cluster configuration
-  @type master_node_config: objects.Node
-  @param master_node_config: Master node configuration
-  @type file_name: string
-  @param file_name: Configuration file path
-
-  @rtype: ssconf.SimpleConfigWriter
-  @returns: Initialized config instance
+  @param version: configuration version
+  @type cluster_config: L{objects.Cluster}
+  @param cluster_config: cluster configuration
+  @type master_node_config: L{objects.Node}
+  @param master_node_config: master node configuration
+  @type cfg_file: string
+  @param cfg_file: configuration file path
 
   """
   nodes = {
     master_node_config.name: master_node_config,
     }
 
+  now = time.time()
   config_data = objects.ConfigData(version=version,
                                    cluster=cluster_config,
                                    nodes=nodes,
                                    instances={},
-                                   serial_no=1)
-  cfg = ssconf.SimpleConfigWriter.FromDict(config_data.ToDict(), cfg_file)
-  cfg.Save()
-
-  return cfg
+                                   serial_no=1,
+                                   ctime=now, mtime=now)
+  utils.WriteFile(cfg_file,
+                  data=serializer.Dump(config_data.ToDict()),
+                  mode=0600)
 
 
 def FinalizeClusterDestroy(master):
@@ -265,34 +359,52 @@ def FinalizeClusterDestroy(master):
   begun in cmdlib.LUDestroyOpcode.
 
   """
-  if not rpc.RpcRunner.call_node_stop_master(master, True):
-    logging.warning("Could not disable the master role")
-  if not rpc.RpcRunner.call_node_leave_cluster(master):
-    logging.warning("Could not shutdown the node daemon and cleanup the node")
-
-
-def SetupNodeDaemon(node, ssh_key_check):
+  cfg = config.ConfigWriter()
+  modify_ssh_setup = cfg.GetClusterInfo().modify_ssh_setup
+  result = rpc.RpcRunner.call_node_stop_master(master, True)
+  msg = result.fail_msg
+  if msg:
+    logging.warning("Could not disable the master role: %s" % msg)
+  result = rpc.RpcRunner.call_node_leave_cluster(master, modify_ssh_setup)
+  msg = result.fail_msg
+  if msg:
+    logging.warning("Could not shutdown the node daemon and cleanup"
+                    " the node: %s", msg)
+
+
+def SetupNodeDaemon(cluster_name, node, ssh_key_check):
   """Add a node to the cluster.
 
   This function must be called before the actual opcode, and will ssh
   to the remote node, copy the needed files, and start ganeti-noded,
   allowing the master to do the rest via normal rpc calls.
 
-  Args:
-    node: fully qualified domain name for the new node
+  @param cluster_name: the cluster name
+  @param node: the name of the new node
+  @param ssh_key_check: whether to do a strict key check
 
   """
-  cfg = ssconf.SimpleConfigReader()
-  sshrunner = ssh.SshRunner(cfg.GetClusterName())
-  gntpem = utils.ReadFile(constants.SSL_CERT_FILE)
+  sshrunner = ssh.SshRunner(cluster_name)
+
+  noded_cert = utils.ReadFile(constants.SSL_CERT_FILE)
+  rapi_cert = utils.ReadFile(constants.RAPI_CERT_FILE)
+  hmac_key = utils.ReadFile(constants.HMAC_CLUSTER_KEY)
+
   # in the base64 pem encoding, neither '!' nor '.' are valid chars,
   # so we use this to detect an invalid certificate; as long as the
   # cert doesn't contain this, the here-document will be correctly
-  # parsed by the shell sequence below
-  if re.search('^!EOF\.', gntpem, re.MULTILINE):
-    raise errors.OpExecError("invalid PEM encoding in the SSL certificate")
-  if not gntpem.endswith("\n"):
-    raise errors.OpExecError("PEM must end with newline")
+  # parsed by the shell sequence below. HMAC keys are hexadecimal strings,
+  # so the same restrictions apply.
+  for content in (noded_cert, rapi_cert, hmac_key):
+    if re.search('^!EOF\.', content, re.MULTILINE):
+      raise errors.OpExecError("invalid SSL certificate or HMAC key")
+
+  if not noded_cert.endswith("\n"):
+    noded_cert += "\n"
+  if not rapi_cert.endswith("\n"):
+    rapi_cert += "\n"
+  if not hmac_key.endswith("\n"):
+    hmac_key += "\n"
 
   # set up inter-node password and certificate and restarts the node daemon
   # and then connect with ssh to set password and start ganeti-noded
@@ -300,8 +412,18 @@ def SetupNodeDaemon(node, ssh_key_check):
   # either by being constants or by the checks above
   mycommand = ("umask 077 && "
                "cat > '%s' << '!EOF.' && \n"
-               "%s!EOF.\n%s restart" %
-               (constants.SSL_CERT_FILE, gntpem,
+               "%s!EOF.\n"
+               "cat > '%s' << '!EOF.' && \n"
+               "%s!EOF.\n"
+               "cat > '%s' << '!EOF.' && \n"
+               "%s!EOF.\n"
+               "chmod 0400 %s %s %s && "
+               "%s restart" %
+               (constants.SSL_CERT_FILE, noded_cert,
+                constants.RAPI_CERT_FILE, rapi_cert,
+                constants.HMAC_CLUSTER_KEY, hmac_key,
+                constants.SSL_CERT_FILE, constants.RAPI_CERT_FILE,
+                constants.HMAC_CLUSTER_KEY,
                 constants.NODE_INITD_SCRIPT))
 
   result = sshrunner.Run(node, 'root', mycommand, batch=False,
@@ -313,70 +435,105 @@ def SetupNodeDaemon(node, ssh_key_check):
                              " output: %s" %
                              (node, result.fail_reason, result.output))
 
-  return 0
-
 
-def MasterFailover():
+def MasterFailover(no_voting=False):
   """Failover the master node.
 
   This checks that we are not already the master, and will cause the
   current master to cease being master, and the non-master to become
   new master.
 
+  @type no_voting: boolean
+  @param no_voting: force the operation without remote nodes agreement
+                      (dangerous)
+
   """
-  cfg = ssconf.SimpleConfigWriter()
+  sstore = ssconf.SimpleStore()
 
-  new_master = utils.HostInfo().name
-  old_master = cfg.GetMasterNode()
-  node_list = cfg.GetNodeList()
+  old_master, new_master = ssconf.GetMasterAndMyself(sstore)
+  node_list = sstore.GetNodeList()
+  mc_list = sstore.GetMasterCandidates()
 
   if old_master == new_master:
     raise errors.OpPrereqError("This commands must be run on the node"
                                " where you want the new master to be."
                                " %s is already the master" %
-                               old_master)
-
-  vote_list = GatherMasterVotes(node_list)
-
-  if vote_list:
-    voted_master = vote_list[0][0]
-    if voted_master is None:
-      raise errors.OpPrereqError("Cluster is inconsistent, most nodes did not"
-                                 " respond.")
-    elif voted_master != old_master:
-      raise errors.OpPrereqError("I have wrong configuration, I believe the"
-                                 " master is %s but the other nodes voted for"
-                                 " %s. Please resync the configuration of"
-                                 " this node." % (old_master, voted_master))
+                               old_master, errors.ECODE_INVAL)
+
+  if new_master not in mc_list:
+    mc_no_master = [name for name in mc_list if name != old_master]
+    raise errors.OpPrereqError("This node is not among the nodes marked"
+                               " as master candidates. Only these nodes"
+                               " can become masters. Current list of"
+                               " master candidates is:\n"
+                               "%s" % ('\n'.join(mc_no_master)),
+                               errors.ECODE_STATE)
+
+  if not no_voting:
+    vote_list = GatherMasterVotes(node_list)
+
+    if vote_list:
+      voted_master = vote_list[0][0]
+      if voted_master is None:
+        raise errors.OpPrereqError("Cluster is inconsistent, most nodes did"
+                                   " not respond.", errors.ECODE_ENVIRON)
+      elif voted_master != old_master:
+        raise errors.OpPrereqError("I have a wrong configuration, I believe"
+                                   " the master is %s but the other nodes"
+                                   " voted %s. Please resync the configuration"
+                                   " of this node." %
+                                   (old_master, voted_master),
+                                   errors.ECODE_STATE)
   # end checks
 
   rcode = 0
 
   logging.info("Setting master to %s, old master: %s", new_master, old_master)
 
-  if not rpc.RpcRunner.call_node_stop_master(old_master, True):
+  result = rpc.RpcRunner.call_node_stop_master(old_master, True)
+  msg = result.fail_msg
+  if msg:
     logging.error("Could not disable the master role on the old master"
-                 " %s, please disable manually", old_master)
-
-  cfg.SetMasterNode(new_master)
-  cfg.Save()
+                 " %s, please disable manually: %s", old_master, msg)
 
   # Here we have a phase where no master should be running
 
-  if not rpc.RpcRunner.call_upload_file(cfg.GetNodeList(),
-                                    constants.CLUSTER_CONF_FILE):
-    logging.error("Could not distribute the new configuration"
-                  " to the other nodes, please check.")
+  # instantiate a real config writer, as we now know we have the
+  # configuration data
+  cfg = config.ConfigWriter()
 
+  cluster_info = cfg.GetClusterInfo()
+  cluster_info.master_node = new_master
+  # this will also regenerate the ssconf files, since we updated the
+  # cluster info
+  cfg.Update(cluster_info, logging.error)
 
-  if not rpc.RpcRunner.call_node_start_master(new_master, True):
+  result = rpc.RpcRunner.call_node_start_master(new_master, True, no_voting)
+  msg = result.fail_msg
+  if msg:
     logging.error("Could not start the master role on the new master"
-                  " %s, please check", new_master)
+                  " %s, please check: %s", new_master, msg)
     rcode = 1
 
   return rcode
 
 
+def GetMaster():
+  """Returns the current master node.
+
+  This is a separate function in bootstrap since it's needed by
+  gnt-cluster, and instead of importing directly ssconf, it's better
+  to abstract it in bootstrap, where we do use ssconf in other
+  functions too.
+
+  """
+  sstore = ssconf.SimpleStore()
+
+  old_master, _ = ssconf.GetMasterAndMyself(sstore)
+
+  return old_master
+
+
 def GatherMasterVotes(node_list):
   """Check the agreement on who is the master.
 
@@ -393,7 +550,7 @@ def GatherMasterVotes(node_list):
 
   @type node_list: list
   @param node_list: the list of nodes to query for master info; the current
-      node wil be removed if it is in the list
+      node will be removed if it is in the list
   @rtype: list
   @return: list of (node, votes)
 
@@ -411,17 +568,24 @@ def GatherMasterVotes(node_list):
     # this should not happen (unless internal error in rpc)
     logging.critical("Can't complete rpc call, aborting master startup")
     return [(None, len(node_list))]
-  positive = negative = 0
-  other_masters = {}
   votes = {}
   for node in results:
-    if not isinstance(results[node], (tuple, list)) or len(results[node]) < 3:
-      # here the rpc layer should have already logged errors
+    nres = results[node]
+    data = nres.payload
+    msg = nres.fail_msg
+    fail = False
+    if msg:
+      logging.warning("Error contacting node %s: %s", node, msg)
+      fail = True
+    elif not isinstance(data, (tuple, list)) or len(data) < 3:
+      logging.warning("Invalid data received from node %s: %s", node, data)
+      fail = True
+    if fail:
       if None not in votes:
         votes[None] = 0
       votes[None] += 1
       continue
-    master_node = results[node][2]
+    master_node = data[2]
     if master_node not in votes:
       votes[master_node] = 0
     votes[master_node] += 1