X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fsrc%2Fmon%2FMonmapMonitor.cc;fp=src%2Fceph%2Fsrc%2Fmon%2FMonmapMonitor.cc;h=7a0fb684de7e93cc1077b8d3354ed95d1e09594c;hb=812ff6ca9fcd3e629e49d4328905f33eee8ca3f5;hp=0000000000000000000000000000000000000000;hpb=15280273faafb77777eab341909a3f495cf248d9;p=stor4nfv.git

diff --git a/src/ceph/src/mon/MonmapMonitor.cc b/src/ceph/src/mon/MonmapMonitor.cc
new file mode 100644
index 0000000..7a0fb68
--- /dev/null
+++ b/src/ceph/src/mon/MonmapMonitor.cc
@@ -0,0 +1,801 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2009 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software 
+ * Foundation.  See file COPYING.
+ * 
+ */
+
+#include "MonmapMonitor.h"
+#include "Monitor.h"
+#include "messages/MMonCommand.h"
+#include "messages/MMonJoin.h"
+
+#include "common/ceph_argparse.h"
+#include "common/errno.h"
+#include <sstream>
+#include "common/config.h"
+#include "common/cmdparse.h"
+
+#include "include/assert.h"
+#include "include/stringify.h"
+
+#define dout_subsys ceph_subsys_mon
+#undef dout_prefix
+#define dout_prefix _prefix(_dout, mon)
+static ostream& _prefix(std::ostream *_dout, Monitor *mon) {
+  return *_dout << "mon." << mon->name << "@" << mon->rank
+		<< "(" << mon->get_state_name()
+		<< ").monmap v" << mon->monmap->epoch << " ";
+}
+
+void MonmapMonitor::create_initial()
+{
+  dout(10) << __func__ << " using current monmap" << dendl;
+  pending_map = *mon->monmap;
+  pending_map.epoch = 1;
+
+  if (g_conf->mon_debug_no_initial_persistent_features) {
+    derr << __func__ << " mon_debug_no_initial_persistent_features=true"
+	 << dendl;
+  } else {
+    // initialize with default persistent features for new clusters
+    pending_map.persistent_features = ceph::features::mon::get_persistent();
+  }
+}
+
+void MonmapMonitor::update_from_paxos(bool *need_bootstrap)
+{
+  version_t version = get_last_committed();
+  if (version <= mon->monmap->get_epoch())
+    return;
+
+  dout(10) << __func__ << " version " << version
+	   << ", my v " << mon->monmap->epoch << dendl;
+  
+  if (need_bootstrap && version != mon->monmap->get_epoch()) {
+    dout(10) << " signaling that we need a bootstrap" << dendl;
+    *need_bootstrap = true;
+  }
+
+  // read and decode
+  monmap_bl.clear();
+  int ret = get_version(version, monmap_bl);
+  assert(ret == 0);
+  assert(monmap_bl.length());
+
+  dout(10) << __func__ << " got " << version << dendl;
+  mon->monmap->decode(monmap_bl);
+
+  if (mon->store->exists("mkfs", "monmap")) {
+    auto t(std::make_shared<MonitorDBStore::Transaction>());
+    t->erase("mkfs", "monmap");
+    mon->store->apply_transaction(t);
+  }
+
+  check_subs();
+}
+
+void MonmapMonitor::create_pending()
+{
+  pending_map = *mon->monmap;
+  pending_map.epoch++;
+  pending_map.last_changed = ceph_clock_now();
+  dout(10) << __func__ << " monmap epoch " << pending_map.epoch << dendl;
+}
+
+void MonmapMonitor::encode_pending(MonitorDBStore::TransactionRef t)
+{
+  dout(10) << __func__ << " epoch " << pending_map.epoch << dendl;
+
+  assert(mon->monmap->epoch + 1 == pending_map.epoch ||
+	 pending_map.epoch == 1);  // special case mkfs!
+  bufferlist bl;
+  pending_map.encode(bl, mon->get_quorum_con_features());
+
+  put_version(t, pending_map.epoch, bl);
+  put_last_committed(t, pending_map.epoch);
+
+  // generate a cluster fingerprint, too?
+  if (pending_map.epoch == 1) {
+    mon->prepare_new_fingerprint(t);
+  }
+}
+
+class C_ApplyFeatures : public Context {
+  MonmapMonitor *svc;
+  mon_feature_t features;
+  public:
+  C_ApplyFeatures(MonmapMonitor *s, const mon_feature_t& f) :
+    svc(s), features(f) { }
+  void finish(int r) override {
+    if (r >= 0) {
+      svc->apply_mon_features(features);
+    } else if (r == -EAGAIN || r == -ECANCELED) {
+      // discard features if we're no longer on the quorum that
+      // established them in the first place.
+      return;
+    } else {
+      assert(0 == "bad C_ApplyFeatures return value");
+    }
+  }
+};
+
+void MonmapMonitor::apply_mon_features(const mon_feature_t& features)
+{
+  if (!is_writeable()) {
+    dout(5) << __func__ << " wait for service to be writeable" << dendl;
+    wait_for_writeable_ctx(new C_ApplyFeatures(this, features));
+    return;
+  }
+
+  assert(is_writeable());
+  assert(features.contains_all(pending_map.persistent_features));
+  // we should never hit this because `features` should be the result
+  // of the quorum's supported features. But if it happens, die.
+  assert(ceph::features::mon::get_supported().contains_all(features));
+
+  mon_feature_t new_features =
+    (pending_map.persistent_features ^
+     (features & ceph::features::mon::get_persistent()));
+
+  if (new_features.empty()) {
+    dout(10) << __func__ << " features match current pending: "
+             << features << dendl;
+    return;
+  }
+
+  if (mon->get_quorum().size() < mon->monmap->size()) {
+    dout(1) << __func__ << " new features " << new_features
+      << " contains features that require a full quorum"
+      << " (quorum size is " << mon->get_quorum().size()
+      << ", requires " << mon->monmap->size() << "): "
+      << new_features
+      << " -- do not enable them!" << dendl;
+    return;
+  }
+
+  new_features |= pending_map.persistent_features;
+
+  dout(5) << __func__ << " applying new features to monmap;"
+          << " had " << pending_map.persistent_features
+          << ", will have " << new_features << dendl;
+  pending_map.persistent_features = new_features;
+  propose_pending();
+}
+
+void MonmapMonitor::on_active()
+{
+  if (get_last_committed() >= 1 && !mon->has_ever_joined) {
+    // make note of the fact that i was, once, part of the quorum.
+    dout(10) << "noting that i was, once, part of an active quorum." << dendl;
+
+    /* This is some form of nasty in-breeding we have between the MonmapMonitor
+       and the Monitor itself. We should find a way to get rid of it given our
+       new architecture. Until then, stick with it since we are a
+       single-threaded process and, truth be told, no one else relies on this
+       thing besides us.
+     */
+    auto t(std::make_shared<MonitorDBStore::Transaction>());
+    t->put(Monitor::MONITOR_NAME, "joined", 1);
+    mon->store->apply_transaction(t);
+    mon->has_ever_joined = true;
+  }
+
+  if (mon->is_leader())
+    mon->clog->info() << "monmap " << *mon->monmap;
+
+  apply_mon_features(mon->get_quorum_mon_features());
+}
+
+bool MonmapMonitor::preprocess_query(MonOpRequestRef op)
+{
+  PaxosServiceMessage *m = static_cast<PaxosServiceMessage*>(op->get_req());
+  switch (m->get_type()) {
+    // READs
+  case MSG_MON_COMMAND:
+    return preprocess_command(op);
+  case MSG_MON_JOIN:
+    return preprocess_join(op);
+  default:
+    ceph_abort();
+    return true;
+  }
+}
+
+void MonmapMonitor::dump_info(Formatter *f)
+{
+  f->dump_unsigned("monmap_first_committed", get_first_committed());
+  f->dump_unsigned("monmap_last_committed", get_last_committed());
+  f->open_object_section("monmap");
+  mon->monmap->dump(f);
+  f->close_section();
+  f->open_array_section("quorum");
+  for (set<int>::iterator q = mon->get_quorum().begin(); q != mon->get_quorum().end(); ++q)
+    f->dump_int("mon", *q);
+  f->close_section();
+}
+
+bool MonmapMonitor::preprocess_command(MonOpRequestRef op)
+{
+  MMonCommand *m = static_cast<MMonCommand*>(op->get_req());
+  int r = -1;
+  bufferlist rdata;
+  stringstream ss;
+
+  map<string, cmd_vartype> cmdmap;
+  if (!cmdmap_from_json(m->cmd, &cmdmap, ss)) {
+    string rs = ss.str();
+    mon->reply_command(op, -EINVAL, rs, rdata, get_last_committed());
+    return true;
+  }
+
+  string prefix;
+  cmd_getval(g_ceph_context, cmdmap, "prefix", prefix);
+
+  MonSession *session = m->get_session();
+  if (!session) {
+    mon->reply_command(op, -EACCES, "access denied", get_last_committed());
+    return true;
+  }
+
+  string format;
+  cmd_getval(g_ceph_context, cmdmap, "format", format, string("plain"));
+  boost::scoped_ptr<Formatter> f(Formatter::create(format));
+
+  if (prefix == "mon stat") {
+    mon->monmap->print_summary(ss);
+    ss << ", election epoch " << mon->get_epoch() << ", leader "
+       << mon->get_leader() << " " << mon->get_leader_name()
+       << ", quorum " << mon->get_quorum() << " " << mon->get_quorum_names();
+    rdata.append(ss);
+    ss.str("");
+    r = 0;
+
+  } else if (prefix == "mon getmap" ||
+             prefix == "mon dump") {
+
+    epoch_t epoch;
+    int64_t epochnum;
+    cmd_getval(g_ceph_context, cmdmap, "epoch", epochnum, (int64_t)0);
+    epoch = epochnum;
+
+    MonMap *p = mon->monmap;
+    if (epoch) {
+      bufferlist bl;
+      r = get_version(epoch, bl);
+      if (r == -ENOENT) {
+        ss << "there is no map for epoch " << epoch;
+        goto reply;
+      }
+      assert(r == 0);
+      assert(bl.length() > 0);
+      p = new MonMap;
+      p->decode(bl);
+    }
+
+    assert(p != NULL);
+
+    if (prefix == "mon getmap") {
+      p->encode(rdata, m->get_connection()->get_features());
+      r = 0;
+      ss << "got monmap epoch " << p->get_epoch();
+    } else if (prefix == "mon dump") {
+      stringstream ds;
+      if (f) {
+        f->open_object_section("monmap");
+        p->dump(f.get());
+        f->open_array_section("quorum");
+        for (set<int>::iterator q = mon->get_quorum().begin();
+            q != mon->get_quorum().end(); ++q) {
+          f->dump_int("mon", *q);
+        }
+        f->close_section();
+        f->close_section();
+        f->flush(ds);
+        r = 0;
+      } else {
+        p->print(ds);
+        r = 0;
+      }
+      rdata.append(ds);
+      ss << "dumped monmap epoch " << p->get_epoch();
+    }
+    if (p != mon->monmap)
+       delete p;
+
+  } else if (prefix == "mon feature ls") {
+   
+    bool list_with_value = false;
+    string with_value;
+    if (cmd_getval(g_ceph_context, cmdmap, "with_value", with_value) &&
+        with_value == "--with-value") {
+      list_with_value = true;
+    }
+
+    MonMap *p = mon->monmap;
+
+    // list features
+    mon_feature_t supported = ceph::features::mon::get_supported();
+    mon_feature_t persistent = ceph::features::mon::get_persistent();
+    mon_feature_t required = p->get_required_features();
+
+    stringstream ds;
+    auto print_feature = [&](mon_feature_t& m_features, const char* m_str) {
+      if (f) {
+        if (list_with_value)
+          m_features.dump_with_value(f.get(), m_str);
+        else
+          m_features.dump(f.get(), m_str);
+      } else {
+        if (list_with_value)
+          m_features.print_with_value(ds);
+        else
+          m_features.print(ds);
+      }
+    };
+
+    if (f) {
+      f->open_object_section("features");
+
+      f->open_object_section("all");
+      print_feature(supported, "supported");
+      print_feature(persistent, "persistent");
+      f->close_section(); // all
+
+      f->open_object_section("monmap");
+      print_feature(p->persistent_features, "persistent");
+      print_feature(p->optional_features, "optional");
+      print_feature(required, "required");
+      f->close_section(); // monmap 
+
+      f->close_section(); // features
+      f->flush(ds);
+
+    } else {
+      ds << "all features" << std::endl
+        << "\tsupported: ";
+      print_feature(supported, nullptr);
+      ds << std::endl
+        << "\tpersistent: ";
+      print_feature(persistent, nullptr);
+      ds << std::endl
+        << std::endl;
+
+      ds << "on current monmap (epoch "
+         << p->get_epoch() << ")" << std::endl
+         << "\tpersistent: ";
+      print_feature(p->persistent_features, nullptr);
+      ds << std::endl
+        // omit optional features in plain-text
+        // makes it easier to read, and they're, currently, empty.
+	 << "\trequired: ";
+      print_feature(required, nullptr);
+      ds << std::endl;
+    }
+    rdata.append(ds);
+    r = 0;
+  }
+
+reply:
+  if (r != -1) {
+    string rs;
+    getline(ss, rs);
+
+    mon->reply_command(op, r, rs, rdata, get_last_committed());
+    return true;
+  } else
+    return false;
+}
+
+
+bool MonmapMonitor::prepare_update(MonOpRequestRef op)
+{
+  PaxosServiceMessage *m = static_cast<PaxosServiceMessage*>(op->get_req());
+  dout(7) << __func__ << " " << *m << " from " << m->get_orig_source_inst() << dendl;
+  
+  switch (m->get_type()) {
+  case MSG_MON_COMMAND:
+    return prepare_command(op);
+  case MSG_MON_JOIN:
+    return prepare_join(op);
+  default:
+    ceph_abort();
+  }
+
+  return false;
+}
+
+bool MonmapMonitor::prepare_command(MonOpRequestRef op)
+{
+  MMonCommand *m = static_cast<MMonCommand*>(op->get_req());
+  stringstream ss;
+  string rs;
+  int err = -EINVAL;
+
+  map<string, cmd_vartype> cmdmap;
+  if (!cmdmap_from_json(m->cmd, &cmdmap, ss)) {
+    string rs = ss.str();
+    mon->reply_command(op, -EINVAL, rs, get_last_committed());
+    return true;
+  }
+
+  string prefix;
+  cmd_getval(g_ceph_context, cmdmap, "prefix", prefix);
+
+  MonSession *session = m->get_session();
+  if (!session) {
+    mon->reply_command(op, -EACCES, "access denied", get_last_committed());
+    return true;
+  }
+
+  /* We should follow the following rules:
+   *
+   * - 'monmap' is the current, consistent version of the monmap
+   * - 'pending_map' is the uncommitted version of the monmap
+   *
+   * All checks for the current state must be made against 'monmap'.
+   * All changes are made against 'pending_map'.
+   *
+   * If there are concurrent operations modifying 'pending_map', please
+   * follow the following rules.
+   *
+   * - if pending_map has already been changed, the second operation must
+   *   wait for the proposal to finish and be run again; This is the easiest
+   *   path to guarantee correctness but may impact performance (i.e., it
+   *   will take longer for the user to get a reply).
+   *
+   * - if the result of the second operation can be guaranteed to be
+   *   idempotent, the operation may reply to the user once the proposal
+   *   finishes; still needs to wait for the proposal to finish.
+   *
+   * - An operation _NEVER_ returns to the user based on pending state.
+   *
+   * If an operation does not modify current stable monmap, it may be
+   * serialized before current pending map, regardless of any change that
+   * has been made to the pending map -- remember, pending is uncommitted
+   * state, thus we are not bound by it.
+   */
+
+  assert(mon->monmap);
+  MonMap &monmap = *mon->monmap;
+
+
+  /* Please note:
+   *
+   * Adding or removing monitors may lead to loss of quorum.
+   *
+   * Because quorum may be lost, it's important to reply something
+   * to the user, lest she end up waiting forever for a reply. And
+   * no reply will ever be sent until quorum is formed again.
+   *
+   * On the other hand, this means we're leaking uncommitted state
+   * to the user. As such, please be mindful of the reply message.
+   *
+   * e.g., 'adding monitor mon.foo' is okay ('adding' is an on-going
+   * operation and conveys its not-yet-permanent nature); whereas
+   * 'added monitor mon.foo' presumes the action has successfully
+   * completed and state has been committed, which may not be true.
+   */
+
+
+  bool propose = false;
+  if (prefix == "mon add") {
+    string name;
+    cmd_getval(g_ceph_context, cmdmap, "name", name);
+    string addrstr;
+    cmd_getval(g_ceph_context, cmdmap, "addr", addrstr);
+    entity_addr_t addr;
+    bufferlist rdata;
+
+    if (!addr.parse(addrstr.c_str())) {
+      err = -EINVAL;
+      ss << "addr " << addrstr << "does not parse";
+      goto reply;
+    }
+
+    if (addr.get_port() == 0) {
+      ss << "port defaulted to " << CEPH_MON_PORT;
+      addr.set_port(CEPH_MON_PORT);
+    }
+
+    /**
+     * If we have a monitor with the same name and different addr, then EEXIST
+     * If we have a monitor with the same addr and different name, then EEXIST
+     * If we have a monitor with the same addr and same name, then wait for
+     * the proposal to finish and return success.
+     * If we don't have the monitor, add it.
+     */
+
+    err = 0;
+    if (!ss.str().empty())
+      ss << "; ";
+
+    do {
+      if (monmap.contains(name)) {
+        if (monmap.get_addr(name) == addr) {
+          // stable map contains monitor with the same name at the same address.
+          // serialize before current pending map.
+          err = 0; // for clarity; this has already been set above.
+          ss << "mon." << name << " at " << addr << " already exists";
+          goto reply;
+        } else {
+          ss << "mon." << name
+             << " already exists at address " << monmap.get_addr(name);
+        }
+      } else if (monmap.contains(addr)) {
+        // we established on the previous branch that name is different
+        ss << "mon." << monmap.get_name(addr)
+           << " already exists at address " << addr;
+      } else {
+        // go ahead and add
+        break;
+      }
+      err = -EEXIST;
+      goto reply;
+    } while (false);
+
+    /* Given there's no delay between proposals on the MonmapMonitor (see
+     * MonmapMonitor::should_propose()), there is no point in checking for
+     * a mismatch between name and addr on pending_map.
+     *
+     * Once we established the monitor does not exist in the committed state,
+     * we can simply go ahead and add the monitor.
+     */
+
+    pending_map.add(name, addr);
+    pending_map.last_changed = ceph_clock_now();
+    ss << "adding mon." << name << " at " << addr;
+    propose = true;
+    dout(0) << __func__ << " proposing new mon." << name << dendl;
+
+  } else if (prefix == "mon remove" ||
+             prefix == "mon rm") {
+    string name;
+    cmd_getval(g_ceph_context, cmdmap, "name", name);
+    if (!monmap.contains(name)) {
+      err = 0;
+      ss << "mon." << name << " does not exist or has already been removed";
+      goto reply;
+    }
+
+    if (monmap.size() == 1) {
+      err = -EINVAL;
+      ss << "error: refusing removal of last monitor " << name;
+      goto reply;
+    }
+
+    /* At the time of writing, there is no risk of races when multiple clients
+     * attempt to use the same name. The reason is simple but may not be
+     * obvious.
+     *
+     * In a nutshell, we do not collate proposals on the MonmapMonitor. As
+     * soon as we return 'true' below, PaxosService::dispatch() will check if
+     * the service should propose, and - if so - the service will be marked as
+     * 'proposing' and a proposal will be triggered. The PaxosService class
+     * guarantees that once a service is marked 'proposing' no further writes
+     * will be handled.
+     *
+     * The decision on whether the service should propose or not is, in this
+     * case, made by MonmapMonitor::should_propose(), which always considers
+     * the proposal delay being 0.0 seconds. This is key for PaxosService to
+     * trigger the proposal immediately.
+     * 0.0 seconds of delay.
+     *
+     * From the above, there's no point in performing further checks on the
+     * pending_map, as we don't ever have multiple proposals in-flight in
+     * this service. As we've established the committed state contains the
+     * monitor, we can simply go ahead and remove it.
+     *
+     * Please note that the code hinges on all of the above to be true. It
+     * has been true since time immemorial and we don't see a good reason
+     * to make it sturdier at this time - mainly because we don't think it's
+     * going to change any time soon, lest for any bug that may be unwillingly
+     * introduced.
+     */
+
+    entity_addr_t addr = pending_map.get_addr(name);
+    pending_map.remove(name);
+    pending_map.last_changed = ceph_clock_now();
+    ss << "removing mon." << name << " at " << addr
+       << ", there will be " << pending_map.size() << " monitors" ;
+    propose = true;
+    err = 0;
+
+  } else if (prefix == "mon feature set") {
+
+    /* PLEASE NOTE:
+     *
+     * We currently only support setting/unsetting persistent features.
+     * This is by design, given at the moment we still don't have optional
+     * features, and, as such, there is no point introducing an interface
+     * to manipulate them. This allows us to provide a cleaner, more
+     * intuitive interface to the user, modifying solely persistent
+     * features.
+     *
+     * In the future we should consider adding another interface to handle
+     * optional features/flags; e.g., 'mon feature flag set/unset', or
+     * 'mon flag set/unset'.
+     */
+    string feature_name;
+    if (!cmd_getval(g_ceph_context, cmdmap, "feature_name", feature_name)) {
+      ss << "missing required feature name";
+      err = -EINVAL;
+      goto reply;
+    }
+
+    mon_feature_t feature;
+    feature = ceph::features::mon::get_feature_by_name(feature_name);
+    if (feature == ceph::features::mon::FEATURE_NONE) {
+      ss << "unknown feature '" << feature_name << "'";
+      err = -ENOENT;
+      goto reply;
+    }
+
+    string sure;
+    if (!cmd_getval(g_ceph_context, cmdmap, "sure", sure) ||
+        sure != "--yes-i-really-mean-it") {
+      ss << "please specify '--yes-i-really-mean-it' if you "
+         << "really, **really** want to set feature '"
+         << feature << "' in the monmap.";
+      err = -EPERM;
+      goto reply;
+    }
+
+    if (!mon->get_quorum_mon_features().contains_all(feature)) {
+      ss << "current quorum does not support feature '" << feature
+         << "'; supported features: "
+         << mon->get_quorum_mon_features();
+      err = -EINVAL;
+      goto reply;
+    }
+
+    ss << "setting feature '" << feature << "'";
+
+    err = 0;
+    if (monmap.persistent_features.contains_all(feature)) {
+      dout(10) << __func__ << " feature '" << feature
+               << "' already set on monmap; no-op." << dendl;
+      goto reply;
+    }
+
+    pending_map.persistent_features.set_feature(feature);
+    pending_map.last_changed = ceph_clock_now();
+    propose = true;
+
+    dout(1) << __func__ << ss.str() << "; new features will be: "
+            << "persistent = " << pending_map.persistent_features
+            // output optional nevertheless, for auditing purposes.
+            << ", optional = " << pending_map.optional_features << dendl;
+    
+  } else {
+    ss << "unknown command " << prefix;
+    err = -EINVAL;
+  }
+
+reply:
+  getline(ss, rs);
+  mon->reply_command(op, err, rs, get_last_committed());
+  // we are returning to the user; do not propose.
+  return propose;
+}
+
+bool MonmapMonitor::preprocess_join(MonOpRequestRef op)
+{
+  MMonJoin *join = static_cast<MMonJoin*>(op->get_req());
+  dout(10) << __func__ << " " << join->name << " at " << join->addr << dendl;
+
+  MonSession *session = join->get_session();
+  if (!session ||
+      !session->is_capable("mon", MON_CAP_W | MON_CAP_X)) {
+    dout(10) << " insufficient caps" << dendl;
+    return true;
+  }
+
+  if (pending_map.contains(join->name) && !pending_map.get_addr(join->name).is_blank_ip()) {
+    dout(10) << " already have " << join->name << dendl;
+    return true;
+  }
+  if (pending_map.contains(join->addr) && pending_map.get_name(join->addr) == join->name) {
+    dout(10) << " already have " << join->addr << dendl;
+    return true;
+  }
+  return false;
+}
+bool MonmapMonitor::prepare_join(MonOpRequestRef op)
+{
+  MMonJoin *join = static_cast<MMonJoin*>(op->get_req());
+  dout(0) << "adding/updating " << join->name << " at " << join->addr << " to monitor cluster" << dendl;
+  if (pending_map.contains(join->name))
+    pending_map.remove(join->name);
+  if (pending_map.contains(join->addr))
+    pending_map.remove(pending_map.get_name(join->addr));
+  pending_map.add(join->name, join->addr);
+  pending_map.last_changed = ceph_clock_now();
+  return true;
+}
+
+bool MonmapMonitor::should_propose(double& delay)
+{
+  delay = 0.0;
+  return true;
+}
+
+void MonmapMonitor::get_health(list<pair<health_status_t, string> >& summary,
+			       list<pair<health_status_t, string> > *detail,
+			       CephContext *cct) const
+{
+  int max = mon->monmap->size();
+  int actual = mon->get_quorum().size();
+  if (actual < max) {
+    ostringstream ss;
+    ss << (max-actual) << " mons down, quorum " << mon->get_quorum() << " " << mon->get_quorum_names();
+    summary.push_back(make_pair(HEALTH_WARN, ss.str()));
+    if (detail) {
+      set<int> q = mon->get_quorum();
+      for (int i=0; i<max; i++) {
+	if (q.count(i) == 0) {
+	  ostringstream ss;
+	  ss << "mon." << mon->monmap->get_name(i) << " (rank " << i
+	     << ") addr " << mon->monmap->get_addr(i)
+	     << " is down (out of quorum)";
+	  detail->push_back(make_pair(HEALTH_WARN, ss.str()));
+	}
+      }
+    }
+  }
+}
+
+int MonmapMonitor::get_monmap(bufferlist &bl)
+{
+  version_t latest_ver = get_last_committed();
+  dout(10) << __func__ << " ver " << latest_ver << dendl;
+
+  if (!mon->store->exists(get_service_name(), stringify(latest_ver)))
+    return -ENOENT;
+
+  int err = get_version(latest_ver, bl);
+  if (err < 0) {
+    dout(1) << __func__ << " error obtaining monmap: "
+            << cpp_strerror(err) << dendl;
+    return err;
+  }
+  return 0;
+}
+
+void MonmapMonitor::check_subs()
+{
+  const string type = "monmap";
+  mon->with_session_map([this, &type](const MonSessionMap& session_map) {
+      auto subs = session_map.subs.find(type);
+      if (subs == session_map.subs.end())
+	return;
+      for (auto sub : *subs->second) {
+	check_sub(sub);
+      }
+    });
+}
+
+void MonmapMonitor::check_sub(Subscription *sub)
+{
+  const auto epoch = mon->monmap->get_epoch();
+  dout(10) << __func__
+	   << " monmap next " << sub->next
+	   << " have " << epoch << dendl;
+  if (sub->next <= epoch) {
+    mon->send_latest_monmap(sub->session->con.get());
+    if (sub->onetime) {
+      mon->with_session_map([this, sub](MonSessionMap& session_map) {
+	  session_map.remove_sub(sub);
+	});
+    } else {
+      sub->next = epoch + 1;
+    }
+  }
+}