Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 877 insertions, 0 deletions

diff --git a/src/mon/HealthMonitor.cc b/src/mon/HealthMonitor.cc
new file mode 100644
index 000000000..a45159e7c
--- /dev/null
+++ b/src/mon/HealthMonitor.cc
@@ -0,0 +1,877 @@
+// -*- 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) 2013 Inktank, Inc
+ *
+ * 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 <stdlib.h>
+#include <limits.h>
+#include <sstream>
+#include <regex>
+#include <time.h>
+#include <iterator>
+
+#include "include/ceph_assert.h"
+#include "include/common_fwd.h"
+#include "include/stringify.h"
+
+#include "mon/Monitor.h"
+#include "mon/HealthMonitor.h"
+
+#include "messages/MMonHealthChecks.h"
+
+#include "common/Formatter.h"
+
+#define dout_subsys ceph_subsys_mon
+#undef dout_prefix
+#define dout_prefix _prefix(_dout, mon, this)
+using namespace TOPNSPC::common;
+
+using namespace std::literals;
+using std::cerr;
+using std::cout;
+using std::dec;
+using std::hex;
+using std::list;
+using std::map;
+using std::make_pair;
+using std::ostream;
+using std::ostringstream;
+using std::pair;
+using std::set;
+using std::setfill;
+using std::string;
+using std::stringstream;
+using std::to_string;
+using std::vector;
+using std::unique_ptr;
+
+using ceph::bufferlist;
+using ceph::decode;
+using ceph::encode;
+using ceph::Formatter;
+using ceph::JSONFormatter;
+using ceph::mono_clock;
+using ceph::mono_time;
+using ceph::parse_timespan;
+using ceph::timespan_str;
+static ostream& _prefix(std::ostream *_dout, const Monitor &mon,
+                        const HealthMonitor *hmon) {
+  return *_dout << "mon." << mon.name << "@" << mon.rank
+		<< "(" << mon.get_state_name() << ").health ";
+}
+
+HealthMonitor::HealthMonitor(Monitor &m, Paxos &p, const string& service_name)
+  : PaxosService(m, p, service_name) {
+}
+
+void HealthMonitor::init()
+{
+  dout(10) << __func__ << dendl;
+}
+
+void HealthMonitor::create_initial()
+{
+  dout(10) << __func__ << dendl;
+}
+
+void HealthMonitor::update_from_paxos(bool *need_bootstrap)
+{
+  version = get_last_committed();
+  dout(10) << __func__ << dendl;
+  load_health();
+
+  bufferlist qbl;
+  mon.store->get(service_name, "quorum", qbl);
+  if (qbl.length()) {
+    auto p = qbl.cbegin();
+    decode(quorum_checks, p);
+  } else {
+    quorum_checks.clear();
+  }
+
+  bufferlist lbl;
+  mon.store->get(service_name, "leader", lbl);
+  if (lbl.length()) {
+    auto p = lbl.cbegin();
+    decode(leader_checks, p);
+  } else {
+    leader_checks.clear();
+  }
+
+  {
+    bufferlist bl;
+    mon.store->get(service_name, "mutes", bl);
+    if (bl.length()) {
+      auto p = bl.cbegin();
+      decode(mutes, p);
+    } else {
+      mutes.clear();
+    }
+  }
+
+  dout(20) << "dump:";
+  JSONFormatter jf(true);
+  jf.open_object_section("health");
+  jf.open_object_section("quorum_health");
+  for (auto& p : quorum_checks) {
+    string s = string("mon.") + stringify(p.first);
+    jf.dump_object(s.c_str(), p.second);
+  }
+  jf.close_section();
+  jf.dump_object("leader_health", leader_checks);
+  jf.close_section();
+  jf.flush(*_dout);
+  *_dout << dendl;
+}
+
+void HealthMonitor::create_pending()
+{
+  dout(10) << " " << version << dendl;
+  pending_mutes = mutes;
+}
+
+void HealthMonitor::encode_pending(MonitorDBStore::TransactionRef t)
+{
+  ++version;
+  dout(10) << " " << version << dendl;
+  put_last_committed(t, version);
+
+  bufferlist qbl;
+  encode(quorum_checks, qbl);
+  t->put(service_name, "quorum", qbl);
+  bufferlist lbl;
+  encode(leader_checks, lbl);
+  t->put(service_name, "leader", lbl);
+  {
+    bufferlist bl;
+    encode(pending_mutes, bl);
+    t->put(service_name, "mutes", bl);
+  }
+
+  health_check_map_t pending_health;
+
+  // combine per-mon details carefully...
+  map<string,set<string>> names; // code -> <mon names>
+  for (auto p : quorum_checks) {
+    for (auto q : p.second.checks) {
+      names[q.first].insert(mon.monmap->get_name(p.first));
+    }
+    pending_health.merge(p.second);
+  }
+  for (auto &p : pending_health.checks) {
+    p.second.summary = std::regex_replace(
+      p.second.summary,
+      std::regex("%hasorhave%"),
+      names[p.first].size() > 1 ? "have" : "has");
+    p.second.summary = std::regex_replace(
+      p.second.summary,
+      std::regex("%names%"), stringify(names[p.first]));
+    p.second.summary = std::regex_replace(
+      p.second.summary,
+      std::regex("%plurals%"),
+      names[p.first].size() > 1 ? "s" : "");
+    p.second.summary = std::regex_replace(
+      p.second.summary,
+      std::regex("%isorare%"),
+      names[p.first].size() > 1 ? "are" : "is");
+  }
+
+  pending_health.merge(leader_checks);
+  encode_health(pending_health, t);
+}
+
+version_t HealthMonitor::get_trim_to() const
+{
+  // we don't actually need *any* old states, but keep a few.
+  if (version > 5) {
+    return version - 5;
+  }
+  return 0;
+}
+
+bool HealthMonitor::preprocess_query(MonOpRequestRef op)
+{
+  auto m = op->get_req<PaxosServiceMessage>();
+  switch (m->get_type()) {
+  case MSG_MON_COMMAND:
+    return preprocess_command(op);
+  case MSG_MON_HEALTH_CHECKS:
+    return false;
+  default:
+    mon.no_reply(op);
+    derr << "Unhandled message type " << m->get_type() << dendl;
+    return true;
+  }
+}
+
+bool HealthMonitor::prepare_update(MonOpRequestRef op)
+{
+  Message *m = op->get_req();
+  dout(7) << "prepare_update " << *m
+	  << " from " << m->get_orig_source_inst() << dendl;
+  switch (m->get_type()) {
+  case MSG_MON_HEALTH_CHECKS:
+    return prepare_health_checks(op);
+  case MSG_MON_COMMAND:
+    return prepare_command(op);
+  default:
+    return false;
+  }
+}
+
+bool HealthMonitor::preprocess_command(MonOpRequestRef op)
+{
+  auto m = op->get_req<MMonCommand>();
+  std::stringstream ss;
+  bufferlist rdata;
+
+  cmdmap_t 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;
+  }
+
+  MonSession *session = op->get_session();
+  if (!session) {
+    mon.reply_command(op, -EACCES, "access denied", rdata,
+		       get_last_committed());
+    return true;
+  }
+  // more sanity checks
+  try {
+    string format;
+    cmd_getval(cmdmap, "format", format);
+    string prefix;
+    cmd_getval(cmdmap, "prefix", prefix);
+  } catch (const bad_cmd_get& e) {
+    mon.reply_command(op, -EINVAL, e.what(), rdata, get_last_committed());
+    return true;
+  }
+  return false;
+}
+
+bool HealthMonitor::prepare_command(MonOpRequestRef op)
+{
+  auto m = op->get_req<MMonCommand>();
+
+  std::stringstream ss;
+  bufferlist rdata;
+
+  cmdmap_t 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;
+  }
+
+  MonSession *session = op->get_session();
+  if (!session) {
+    mon.reply_command(op, -EACCES, "access denied", rdata, get_last_committed());
+    return true;
+  }
+
+  string format;
+  cmd_getval(cmdmap, "format", format, string("plain"));
+  boost::scoped_ptr<Formatter> f(Formatter::create(format));
+
+  string prefix;
+  cmd_getval(cmdmap, "prefix", prefix);
+
+  int r = 0;
+
+  if (prefix == "health mute") {
+    string code;
+    bool sticky = false;
+    if (!cmd_getval(cmdmap, "code", code) ||
+	code == "") {
+      r = -EINVAL;
+      ss << "must specify an alert code to mute";
+      goto out;
+    }
+    cmd_getval(cmdmap, "sticky", sticky);
+    string ttl_str;
+    utime_t ttl;
+    if (cmd_getval(cmdmap, "ttl", ttl_str)) {
+      auto secs = parse_timespan(ttl_str);
+      if (secs == 0s) {
+	r = -EINVAL;
+	ss << "not a valid duration: " << ttl_str;
+	goto out;
+      }
+      ttl = ceph_clock_now();
+      ttl += std::chrono::duration<double>(secs).count();
+    }
+    health_check_map_t all;
+    gather_all_health_checks(&all);
+    string summary;
+    int64_t count = 0;
+    if (!sticky) {
+      auto p = all.checks.find(code);
+      if (p == all.checks.end()) {
+	r = -ENOENT;
+	ss << "health alert " << code << " is not currently raised";
+	goto out;
+      }
+      count = p->second.count;
+      summary = p->second.summary;
+    }
+    auto& m = pending_mutes[code];
+    m.code = code;
+    m.ttl = ttl;
+    m.sticky = sticky;
+    m.summary = summary;
+    m.count = count;
+  } else if (prefix == "health unmute") {
+    string code;
+    if (cmd_getval(cmdmap, "code", code)) {
+      pending_mutes.erase(code);
+    } else {
+      pending_mutes.clear();
+    }
+  } else {
+    ss << "Command '" << prefix << "' not implemented!";
+    r = -ENOSYS;
+  }
+
+out:
+  dout(4) << __func__ << " done, r=" << r << dendl;
+  /* Compose response */
+  string rs;
+  getline(ss, rs);
+
+  if (r >= 0) {
+    // success.. delay reply
+    wait_for_finished_proposal(op, new Monitor::C_Command(mon, op, r, rs,
+					      get_last_committed() + 1));
+    return true;
+  } else {
+    // reply immediately
+    mon.reply_command(op, r, rs, rdata, get_last_committed());
+    return false;
+  }
+}
+
+bool HealthMonitor::prepare_health_checks(MonOpRequestRef op)
+{
+  auto m = op->get_req<MMonHealthChecks>();
+  // no need to check if it's changed, the peon has done so
+  quorum_checks[m->get_source().num()] = std::move(m->health_checks);
+  return true;
+}
+
+void HealthMonitor::tick()
+{
+  if (!is_active()) {
+    return;
+  }
+  dout(10) << __func__ << dendl;
+  bool changed = false;
+  if (check_member_health()) {
+    changed = true;
+  }
+  if (!mon.is_leader()) {
+    return;
+  }
+  if (check_leader_health()) {
+    changed = true;
+  }
+  if (check_mutes()) {
+    changed = true;
+  }
+  if (changed) {
+    propose_pending();
+  }
+}
+
+bool HealthMonitor::check_mutes()
+{
+  bool changed = true;
+  auto now = ceph_clock_now();
+  health_check_map_t all;
+  gather_all_health_checks(&all);
+  auto p = pending_mutes.begin();
+  while (p != pending_mutes.end()) {
+    if (p->second.ttl != utime_t() &&
+	p->second.ttl <= now) {
+      mon.clog->info() << "Health alert mute " << p->first
+			<< " cleared (passed TTL " << p->second.ttl << ")";
+      p = pending_mutes.erase(p);
+      changed = true;
+      continue;
+    }
+    if (!p->second.sticky) {
+      auto q = all.checks.find(p->first);
+      if (q == all.checks.end()) {
+	mon.clog->info() << "Health alert mute " << p->first
+			  << " cleared (health alert cleared)";
+	p = pending_mutes.erase(p);
+	changed = true;
+	continue;
+      }
+      if (p->second.count) {
+	// count-based mute
+	if (q->second.count > p->second.count) {
+	  mon.clog->info() << "Health alert mute " << p->first
+			    << " cleared (count increased from " << p->second.count
+			    << " to " << q->second.count << ")";
+	  p = pending_mutes.erase(p);
+	  changed = true;
+	  continue;
+	}
+	if (q->second.count < p->second.count) {
+	  // rachet down the mute
+	  dout(10) << __func__ << " mute " << p->first << " count "
+		   << p->second.count << " -> " << q->second.count
+		   << dendl;
+	  p->second.count = q->second.count;
+	  changed = true;
+	}
+      } else {
+	// summary-based mute
+	if (p->second.summary != q->second.summary) {
+	  mon.clog->info() << "Health alert mute " << p->first
+			    << " cleared (summary changed)";
+	  p = pending_mutes.erase(p);
+	  changed = true;
+	  continue;
+	}
+      }
+    }
+    ++p;
+  }
+  return changed;
+}
+
+void HealthMonitor::gather_all_health_checks(health_check_map_t *all)
+{
+  for (auto& svc : mon.paxos_service) {
+    all->merge(svc->get_health_checks());
+  }
+}
+
+health_status_t HealthMonitor::get_health_status(
+  bool want_detail,
+  Formatter *f,
+  std::string *plain,
+  const char *sep1,
+  const char *sep2)
+{
+  health_check_map_t all;
+  gather_all_health_checks(&all);
+  health_status_t r = HEALTH_OK;
+  for (auto& p : all.checks) {
+    if (!mutes.count(p.first)) {
+      if (r > p.second.severity) {
+	r = p.second.severity;
+      }
+    }
+  }
+  if (f) {
+    f->open_object_section("health");
+    f->dump_stream("status") << r;
+    f->open_object_section("checks");
+    for (auto& p : all.checks) {
+      f->open_object_section(p.first.c_str());
+      p.second.dump(f, want_detail);
+      f->dump_bool("muted", mutes.count(p.first));
+      f->close_section();
+    }
+    f->close_section();
+    f->open_array_section("mutes");
+    for (auto& p : mutes) {
+      f->dump_object("mute", p.second);
+    }
+    f->close_section();
+    f->close_section();
+  } else {
+    auto now = ceph_clock_now();
+    // one-liner: HEALTH_FOO[ thing1[; thing2 ...]]
+    string summary;
+    for (auto& p : all.checks) {
+      if (!mutes.count(p.first)) {
+	if (!summary.empty()) {
+	  summary += sep2;
+	}
+	summary += p.second.summary;
+      }
+    }
+    *plain = stringify(r);
+    if (summary.size()) {
+      *plain += sep1;
+      *plain += summary;
+    }
+    if (!mutes.empty()) {
+      if (summary.size()) {
+	*plain += sep2;
+      } else {
+	*plain += sep1;
+      }
+      *plain += "(muted:";
+      for (auto& p : mutes) {
+	*plain += " ";
+	*plain += p.first;
+	if (p.second.ttl) {
+	  if (p.second.ttl > now) {
+	    auto left = p.second.ttl;
+	    left -= now;
+	    *plain += "("s + utimespan_str(left) + ")";
+	  } else {
+	    *plain += "(0s)";
+	  }
+	}
+      }
+      *plain += ")";
+    }
+    *plain += "\n";
+    // detail
+    if (want_detail) {
+      for (auto& p : all.checks) {
+	auto q = mutes.find(p.first);
+	if (q != mutes.end()) {
+	  *plain += "(MUTED";
+	  if (q->second.ttl != utime_t()) {
+	    if (q->second.ttl > now) {
+	      auto left = q->second.ttl;
+	      left -= now;
+	      *plain += " ttl ";
+	      *plain += utimespan_str(left);
+	    } else {
+	      *plain += "0s";
+	    }
+	  }
+	  if (q->second.sticky) {
+	    *plain += ", STICKY";
+	  }
+	  *plain += ") ";
+	}
+	*plain += "["s + short_health_string(p.second.severity) + "] " +
+	  p.first + ": " + p.second.summary + "\n";
+	for (auto& d : p.second.detail) {
+	  *plain += "    ";
+	  *plain += d;
+	  *plain += "\n";
+	}
+      }
+    }
+  }
+  return r;
+}
+
+bool HealthMonitor::check_member_health()
+{
+  dout(20) << __func__ << dendl;
+  bool changed = false;
+  const auto max = g_conf().get_val<uint64_t>("mon_health_max_detail");
+
+  // snapshot of usage
+  DataStats stats;
+  get_fs_stats(stats.fs_stats, g_conf()->mon_data.c_str());
+  map<string,uint64_t> extra;
+  uint64_t store_size = mon.store->get_estimated_size(extra);
+  ceph_assert(store_size > 0);
+  stats.store_stats.bytes_total = store_size;
+  stats.store_stats.bytes_sst = extra["sst"];
+  stats.store_stats.bytes_log = extra["log"];
+  stats.store_stats.bytes_misc = extra["misc"];
+  stats.last_update = ceph_clock_now();
+  dout(10) << __func__ << " avail " << stats.fs_stats.avail_percent << "%"
+	   << " total " << byte_u_t(stats.fs_stats.byte_total)
+	   << ", used " << byte_u_t(stats.fs_stats.byte_used)
+	   << ", avail " << byte_u_t(stats.fs_stats.byte_avail) << dendl;
+
+  // MON_DISK_{LOW,CRIT,BIG}
+  health_check_map_t next;
+  if (stats.fs_stats.avail_percent <= g_conf()->mon_data_avail_crit) {
+    stringstream ss, ss2;
+    ss << "mon%plurals% %names% %isorare% very low on available space";
+    auto& d = next.add("MON_DISK_CRIT", HEALTH_ERR, ss.str(), 1);
+    ss2 << "mon." << mon.name << " has " << stats.fs_stats.avail_percent
+	<< "% avail";
+    d.detail.push_back(ss2.str());
+  } else if (stats.fs_stats.avail_percent <= g_conf()->mon_data_avail_warn) {
+    stringstream ss, ss2;
+    ss << "mon%plurals% %names% %isorare% low on available space";
+    auto& d = next.add("MON_DISK_LOW", HEALTH_WARN, ss.str(), 1);
+    ss2 << "mon." << mon.name << " has " << stats.fs_stats.avail_percent
+	<< "% avail";
+    d.detail.push_back(ss2.str());
+  }
+  if (stats.store_stats.bytes_total >= g_conf()->mon_data_size_warn) {
+    stringstream ss, ss2;
+    ss << "mon%plurals% %names% %isorare% using a lot of disk space";
+    auto& d = next.add("MON_DISK_BIG", HEALTH_WARN, ss.str(), 1);
+    ss2 << "mon." << mon.name << " is "
+	<< byte_u_t(stats.store_stats.bytes_total)
+	<< " >= mon_data_size_warn ("
+	<< byte_u_t(g_conf()->mon_data_size_warn) << ")";
+    d.detail.push_back(ss2.str());
+  }
+
+  // OSD_NO_DOWN_OUT_INTERVAL
+  {
+    // Warn if 'mon_osd_down_out_interval' is set to zero.
+    // Having this option set to zero on the leader acts much like the
+    // 'noout' flag.  It's hard to figure out what's going wrong with clusters
+    // without the 'noout' flag set but acting like that just the same, so
+    // we report a HEALTH_WARN in case this option is set to zero.
+    // This is an ugly hack to get the warning out, but until we find a way
+    // to spread global options throughout the mon cluster and have all mons
+    // using a base set of the same options, we need to work around this sort
+    // of things.
+    // There's also the obvious drawback that if this is set on a single
+    // monitor on a 3-monitor cluster, this warning will only be shown every
+    // third monitor connection.
+    if (g_conf()->mon_warn_on_osd_down_out_interval_zero &&
+        g_conf()->mon_osd_down_out_interval == 0) {
+      ostringstream ss, ds;
+      ss << "mon%plurals% %names% %hasorhave% mon_osd_down_out_interval set to 0";
+      auto& d = next.add("OSD_NO_DOWN_OUT_INTERVAL", HEALTH_WARN, ss.str(), 1);
+      ds << "mon." << mon.name << " has mon_osd_down_out_interval set to 0";
+      d.detail.push_back(ds.str());
+    }
+  }
+
+  // AUTH_INSECURE_GLOBAL_ID_RECLAIM
+  if (g_conf().get_val<bool>("mon_warn_on_insecure_global_id_reclaim") &&
+      g_conf().get_val<bool>("auth_allow_insecure_global_id_reclaim")) {
+    // Warn if there are any clients that are insecurely renewing their global_id
+    std::lock_guard l(mon.session_map_lock);
+    list<std::string> detail;
+    for (auto p = mon.session_map.sessions.begin();
+	 p != mon.session_map.sessions.end();
+	 ++p) {
+      if ((*p)->global_id_status == global_id_status_t::RECLAIM_INSECURE) {
+	ostringstream ds;
+	ds << (*p)->entity_name << " at " << (*p)->addrs
+	   << " is using insecure global_id reclaim";
+	detail.push_back(ds.str());
+	if (detail.size() >= max) {
+	  detail.push_back("...");
+	  break;
+	}
+      }
+    }
+    if (!detail.empty()) {
+      ostringstream ss;
+      ss << "client%plurals% %isorare% using insecure global_id reclaim";
+      auto& d = next.add("AUTH_INSECURE_GLOBAL_ID_RECLAIM", HEALTH_WARN, ss.str(),
+			 detail.size());
+      d.detail.swap(detail);
+    }
+  }
+  // AUTH_INSECURE_GLOBAL_ID_RECLAIM_ALLOWED
+  if (g_conf().get_val<bool>("mon_warn_on_insecure_global_id_reclaim_allowed") &&
+      g_conf().get_val<bool>("auth_allow_insecure_global_id_reclaim")) {
+    ostringstream ss, ds;
+    ss << "mon%plurals% %isorare% allowing insecure global_id reclaim";
+    auto& d = next.add("AUTH_INSECURE_GLOBAL_ID_RECLAIM_ALLOWED", HEALTH_WARN, ss.str(), 1);
+    ds << "mon." << mon.name << " has auth_allow_insecure_global_id_reclaim set to true";
+    d.detail.push_back(ds.str());
+  }
+
+  auto p = quorum_checks.find(mon.rank);
+  if (p == quorum_checks.end()) {
+    if (next.empty()) {
+      return false;
+    }
+  } else {
+    if (p->second == next) {
+      return false;
+    }
+  }
+
+  if (mon.is_leader()) {
+    // prepare to propose
+    quorum_checks[mon.rank] = next;
+    changed = true;
+  } else {
+    // tell the leader
+    mon.send_mon_message(new MMonHealthChecks(next), mon.get_leader());
+  }
+
+  return changed;
+}
+
+bool HealthMonitor::check_leader_health()
+{
+  dout(20) << __func__ << dendl;
+  bool changed = false;
+
+  // prune quorum_health
+  {
+    auto& qset = mon.get_quorum();
+    auto p = quorum_checks.begin();
+    while (p != quorum_checks.end()) {
+      if (qset.count(p->first) == 0) {
+	p = quorum_checks.erase(p);
+	changed = true;
+      } else {
+	++p;
+      }
+    }
+  }
+
+  health_check_map_t next;
+
+ // DAEMON_OLD_VERSION
+  if (g_conf().get_val<bool>("mon_warn_on_older_version")) {
+    check_for_older_version(&next);
+  }
+  // MON_DOWN
+  check_for_mon_down(&next);
+  // MON_CLOCK_SKEW
+  check_for_clock_skew(&next);
+  // MON_MSGR2_NOT_ENABLED
+  if (g_conf().get_val<bool>("mon_warn_on_msgr2_not_enabled")) {
+    check_if_msgr2_enabled(&next);
+  }
+
+  if (next != leader_checks) {
+    changed = true;
+    leader_checks = next;
+  }
+  return changed;
+}
+
+void HealthMonitor::check_for_older_version(health_check_map_t *checks)
+{
+  static ceph::coarse_mono_time old_version_first_time =
+    ceph::coarse_mono_clock::zero();
+
+  auto now = ceph::coarse_mono_clock::now();
+  if (ceph::coarse_mono_clock::is_zero(old_version_first_time)) {
+    old_version_first_time = now;
+  }
+  const auto warn_delay = g_conf().get_val<std::chrono::seconds>("mon_warn_older_version_delay");
+  if (now - old_version_first_time > warn_delay) {
+    std::map<string, std::list<string> > all_versions;
+    mon.get_all_versions(all_versions);
+    if (all_versions.size() > 1) {
+      dout(20) << __func__ << " all_versions=" << all_versions << dendl;
+      // The last entry has the largest version
+      dout(20) << __func__ << " highest version daemon count "
+	       << all_versions.rbegin()->second.size() << dendl;
+      // Erase last element (the highest version running)
+      all_versions.erase(all_versions.rbegin()->first);
+      ceph_assert(all_versions.size() > 0);
+      ostringstream ss;
+      unsigned daemon_count = 0;
+      for (auto& g : all_versions) {
+	daemon_count += g.second.size();
+      }
+      int ver_count = all_versions.size();
+      ceph_assert(!(daemon_count == 1 && ver_count != 1));
+      ss << "There " << (daemon_count == 1 ? "is a daemon" : "are daemons")
+	 << " running " << (ver_count > 1 ? "multiple old versions" : "an older version")  << " of ceph";
+      health_status_t status;
+      if (ver_count > 1)
+	status = HEALTH_ERR;
+      else
+	status = HEALTH_WARN;
+      auto& d = checks->add("DAEMON_OLD_VERSION", status, ss.str(), all_versions.size());
+      for (auto& g : all_versions) {
+	ostringstream ds;
+	for (auto& i : g.second) { // Daemon list
+	  ds << i << " ";
+	}
+	ds << (g.second.size() == 1 ? "is" : "are")
+	   << " running an older version of ceph: " << g.first;
+	d.detail.push_back(ds.str());
+      }
+    } else {
+      old_version_first_time = ceph::coarse_mono_clock::zero();
+    }
+  }
+}
+
+void HealthMonitor::check_for_mon_down(health_check_map_t *checks)
+{
+  int max = mon.monmap->size();
+  int actual = mon.get_quorum().size();
+  const auto now = ceph::real_clock::now();
+  if (actual < max &&
+      now > mon.monmap->created.to_real_time() + g_conf().get_val<std::chrono::seconds>("mon_down_mkfs_grace")) {
+    ostringstream ss;
+    ss << (max-actual) << "/" << max << " mons down, quorum "
+       << mon.get_quorum_names();
+    auto& d = checks->add("MON_DOWN", HEALTH_WARN, ss.str(), max - actual);
+    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_addrs(i)
+	   << " is down (out of quorum)";
+	d.detail.push_back(ss.str());
+      }
+    }
+  }
+}
+
+void HealthMonitor::check_for_clock_skew(health_check_map_t *checks)
+{
+  if (!mon.timecheck_skews.empty()) {
+    list<string> warns;
+    list<string> details;
+    for (auto& i : mon.timecheck_skews) {
+      double skew = i.second;
+      double latency = mon.timecheck_latencies[i.first];
+      string name = mon.monmap->get_name(i.first);
+      ostringstream tcss;
+      health_status_t tcstatus = mon.timecheck_status(tcss, skew, latency);
+      if (tcstatus != HEALTH_OK) {
+	warns.push_back(name);
+	ostringstream tmp_ss;
+	tmp_ss << "mon." << name << " " << tcss.str()
+	       << " (latency " << latency << "s)";
+	details.push_back(tmp_ss.str());
+      }
+    }
+    if (!warns.empty()) {
+      ostringstream ss;
+      ss << "clock skew detected on";
+      while (!warns.empty()) {
+	ss << " mon." << warns.front();
+	warns.pop_front();
+	if (!warns.empty())
+	  ss << ",";
+      }
+      auto& d = checks->add("MON_CLOCK_SKEW", HEALTH_WARN, ss.str(), details.size());
+      d.detail.swap(details);
+    }
+  }
+}
+
+void HealthMonitor::check_if_msgr2_enabled(health_check_map_t *checks)
+{
+  if (g_conf().get_val<bool>("ms_bind_msgr2") &&
+      mon.monmap->get_required_features().contains_all(
+	ceph::features::mon::FEATURE_NAUTILUS)) {
+    list<string> details;
+    for (auto& i : mon.monmap->mon_info) {
+      if (!i.second.public_addrs.has_msgr2()) {
+	ostringstream ds;
+	ds << "mon." << i.first << " is not bound to a msgr2 port, only "
+	   << i.second.public_addrs;
+	details.push_back(ds.str());
+      }
+    }
+    if (!details.empty()) {
+      ostringstream ss;
+      ss << details.size() << " monitors have not enabled msgr2";
+      auto &d = checks->add("MON_MSGR2_NOT_ENABLED", HEALTH_WARN, ss.str(),
+			    details.size());
+      d.detail.swap(details);
+    }
+  }
+}