16 files changed, 1898 insertions, 0 deletions

diff --git a/src/crimson/osd/CMakeLists.txt b/src/crimson/osd/CMakeLists.txt
new file mode 100644
index 00000000..e86a11b5
--- /dev/null
+++ b/src/crimson/osd/CMakeLists.txt
@@ -0,0 +1,10 @@
+add_executable(crimson-osd
+  chained_dispatchers.cc
+  heartbeat.cc
+  main.cc
+  osd.cc
+  osd_meta.cc
+  pg.cc
+  pg_meta.cc)
+target_link_libraries(crimson-osd
+  crimson-common crimson-os crimson)
diff --git a/src/crimson/osd/chained_dispatchers.cc b/src/crimson/osd/chained_dispatchers.cc
new file mode 100644
index 00000000..da4aa269
--- /dev/null
+++ b/src/crimson/osd/chained_dispatchers.cc
@@ -0,0 +1,72 @@
+#include "chained_dispatchers.h"
+#include "crimson/net/Connection.h"
+
+
+seastar::future<>
+ChainedDispatchers::ms_dispatch(ceph::net::ConnectionRef conn,
+                                MessageRef m) {
+  return seastar::do_for_each(dispatchers, [conn, m](Dispatcher* dispatcher) {
+    return dispatcher->ms_dispatch(conn, m);
+  });
+}
+
+seastar::future<>
+ChainedDispatchers::ms_handle_accept(ceph::net::ConnectionRef conn) {
+  return seastar::do_for_each(dispatchers, [conn](Dispatcher* dispatcher) {
+    return dispatcher->ms_handle_accept(conn);
+  });
+}
+
+seastar::future<>
+ChainedDispatchers::ms_handle_connect(ceph::net::ConnectionRef conn) {
+  return seastar::do_for_each(dispatchers, [conn](Dispatcher* dispatcher) {
+    return dispatcher->ms_handle_connect(conn);
+  });
+}
+
+seastar::future<>
+ChainedDispatchers::ms_handle_reset(ceph::net::ConnectionRef conn) {
+  return seastar::do_for_each(dispatchers, [conn](Dispatcher* dispatcher) {
+    return dispatcher->ms_handle_reset(conn);
+  });
+}
+
+seastar::future<>
+ChainedDispatchers::ms_handle_remote_reset(ceph::net::ConnectionRef conn) {
+  return seastar::do_for_each(dispatchers, [conn](Dispatcher* dispatcher) {
+    return dispatcher->ms_handle_remote_reset(conn);
+  });
+}
+
+seastar::future<std::unique_ptr<AuthAuthorizer>>
+ChainedDispatchers::ms_get_authorizer(peer_type_t peer_type)
+{
+  // since dispatcher returns a nullptr if it does not have the authorizer,
+  // let's use the chain-of-responsibility pattern here.
+  struct Params {
+    peer_type_t peer_type;
+    std::deque<Dispatcher*>::iterator first, last;
+  } params = {peer_type, dispatchers.begin(), dispatchers.end()};
+  return seastar::do_with(Params{params}, [this] (Params& params) {
+    using result_t = std::unique_ptr<AuthAuthorizer>;
+    return seastar::repeat_until_value([&] () {
+      auto& first = params.first;
+      if (first == params.last) {
+        // just give up
+        return seastar::make_ready_future<std::optional<result_t>>(result_t{});
+      } else {
+        return (*first)->ms_get_authorizer(params.peer_type)
+          .then([&] (auto&& auth)-> std::optional<result_t> {
+          if (auth) {
+            // hooray!
+            return std::move(auth);
+          } else {
+            // try next one
+            ++first;
+            return {};
+          }
+        });
+      }
+    });
+  });
+}	 
diff --git a/src/crimson/osd/chained_dispatchers.h b/src/crimson/osd/chained_dispatchers.h
new file mode 100644
index 00000000..c3040836
--- /dev/null
+++ b/src/crimson/osd/chained_dispatchers.h
@@ -0,0 +1,32 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*- 
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <deque>
+#include "crimson/net/Dispatcher.h"
+
+// in existing Messenger, dispatchers are put into a chain as described by
+// chain-of-responsibility pattern. we could do the same to stop processing
+// the message once any of the dispatchers claims this message, and prevent
+// other dispatchers from reading it. but this change is more involved as
+// it requires changing the ms_ methods to return a bool. so as an intermediate 
+// solution, we are using an observer dispatcher to notify all the interested
+// or unintersted parties.
+class ChainedDispatchers : public ceph::net::Dispatcher {
+  std::deque<Dispatcher*> dispatchers;
+public:
+  void push_front(Dispatcher* dispatcher) {
+    dispatchers.push_front(dispatcher);
+  }
+  void push_back(Dispatcher* dispatcher) {
+    dispatchers.push_back(dispatcher);
+  }
+  seastar::future<> ms_dispatch(ceph::net::ConnectionRef conn, MessageRef m) override;
+  seastar::future<> ms_handle_accept(ceph::net::ConnectionRef conn) override;
+  seastar::future<> ms_handle_connect(ceph::net::ConnectionRef conn) override;
+  seastar::future<> ms_handle_reset(ceph::net::ConnectionRef conn) override;
+  seastar::future<> ms_handle_remote_reset(ceph::net::ConnectionRef conn) override;
+  seastar::future<std::unique_ptr<AuthAuthorizer>>
+  ms_get_authorizer(peer_type_t peer_type) override;
+};
diff --git a/src/crimson/osd/heartbeat.cc b/src/crimson/osd/heartbeat.cc
new file mode 100644
index 00000000..6dfefb3b
--- /dev/null
+++ b/src/crimson/osd/heartbeat.cc
@@ -0,0 +1,415 @@
+#include "heartbeat.h"
+
+#include <boost/range/join.hpp>
+
+#include "messages/MOSDPing.h"
+#include "messages/MOSDFailure.h"
+
+#include "crimson/common/config_proxy.h"
+#include "crimson/net/Connection.h"
+#include "crimson/net/Messenger.h"
+#include "crimson/osd/osdmap_service.h"
+#include "crimson/mon/MonClient.h"
+
+#include "osd/OSDMap.h"
+
+using ceph::common::local_conf;
+
+namespace {
+  seastar::logger& logger() {
+    return ceph::get_logger(ceph_subsys_osd);
+  }
+
+  template<typename Message, typename... Args>
+  Ref<Message> make_message(Args&&... args)
+  {
+    return {new Message{std::forward<Args>(args)...}, false};
+  }
+}
+
+Heartbeat::Heartbeat(int whoami,
+                     uint32_t nonce,
+                     const OSDMapService& service,
+                     ceph::mon::Client& monc)
+  : whoami{whoami},
+    nonce{nonce},
+    service{service},
+    monc{monc},
+    timer{[this] {send_heartbeats();}}
+{}
+
+seastar::future<> Heartbeat::start(entity_addrvec_t front_addrs,
+                                   entity_addrvec_t back_addrs)
+{
+  logger().info("heartbeat: start");
+  // i only care about the address, so any unused port would work
+  for (auto& addr : boost::join(front_addrs.v, back_addrs.v)) {
+    addr.set_port(0);
+  }
+  return seastar::when_all_succeed(
+      ceph::net::Messenger::create(entity_name_t::OSD(whoami),
+                                   "hb_front",
+                                   nonce,
+                                   seastar::engine().cpu_id())
+        .then([this, front_addrs] (auto msgr) {
+          front_msgr = msgr;
+          return start_messenger(front_msgr, front_addrs);
+        }),
+      ceph::net::Messenger::create(entity_name_t::OSD(whoami),
+                                   "hb_back",
+                                   nonce,
+                                   seastar::engine().cpu_id())
+        .then([this, back_addrs] (auto msgr) {
+          back_msgr = msgr;
+          return start_messenger(back_msgr, back_addrs);
+        }))
+    .then([this] {
+      timer.arm_periodic(
+        std::chrono::seconds(local_conf()->osd_heartbeat_interval));
+    });
+}
+
+seastar::future<>
+Heartbeat::start_messenger(ceph::net::Messenger* msgr,
+                           const entity_addrvec_t& addrs)
+{
+  if (local_conf()->ms_crc_data) {
+    msgr->set_crc_data();
+  }
+  if (local_conf()->ms_crc_header) {
+    msgr->set_crc_header();
+  }
+  return msgr->try_bind(addrs,
+                        local_conf()->ms_bind_port_min,
+                        local_conf()->ms_bind_port_max).then([msgr, this] {
+    return msgr->start(this);
+  });
+}
+
+seastar::future<> Heartbeat::stop()
+{
+  return seastar::when_all_succeed(front_msgr->shutdown(),
+                                   back_msgr->shutdown());
+}
+
+const entity_addrvec_t& Heartbeat::get_front_addrs() const
+{
+  return front_msgr->get_myaddrs();
+}
+
+const entity_addrvec_t& Heartbeat::get_back_addrs() const
+{
+  return back_msgr->get_myaddrs();
+}
+
+seastar::future<> Heartbeat::add_peer(osd_id_t peer, epoch_t epoch)
+{
+  auto found = peers.find(peer);
+  if (found == peers.end()) {
+    logger().info("add_peer({})", peer);
+    auto osdmap = service.get_map();
+    // TODO: msgr v2
+    return seastar::when_all_succeed(
+        front_msgr->connect(osdmap->get_hb_front_addrs(peer).legacy_addr(),
+                            CEPH_ENTITY_TYPE_OSD),
+        back_msgr->connect(osdmap->get_hb_back_addrs(peer).legacy_addr(),
+                           CEPH_ENTITY_TYPE_OSD))
+      .then([this, peer, epoch] (auto xcon_front, auto xcon_back) {
+        PeerInfo info;
+        // sharded-messenger compatible mode
+        info.con_front = xcon_front->release();
+        info.con_back = xcon_back->release();
+        info.epoch = epoch;
+        peers.emplace(peer, std::move(info));
+      });
+  } else {
+    found->second.epoch = epoch;
+    return seastar::now();
+  }
+}
+
+seastar::future<Heartbeat::osds_t> Heartbeat::remove_down_peers()
+{
+  osds_t osds;
+  for (auto& peer : peers) {
+    osds.push_back(peer.first);
+  }
+  return seastar::map_reduce(std::move(osds),
+    [this](auto& osd) {
+      auto osdmap = service.get_map();
+      if (!osdmap->is_up(osd)) {
+        return remove_peer(osd).then([] {
+          return seastar::make_ready_future<osd_id_t>(-1);
+        });
+      } else if (peers[osd].epoch < osdmap->get_epoch()) {
+        return seastar::make_ready_future<osd_id_t>(osd);
+      } else {
+        return seastar::make_ready_future<osd_id_t>(-1);
+      }
+    }, osds_t{},
+    [this](osds_t&& extras, osd_id_t extra) {
+      if (extra >= 0) {
+        extras.push_back(extra);
+      }
+      return extras;
+    });
+}
+
+void Heartbeat::add_reporter_peers(int whoami)
+{
+  auto osdmap = service.get_map();
+  // include next and previous up osds to ensure we have a fully-connected set
+  set<int> want;
+  if (auto next = osdmap->get_next_up_osd_after(whoami); next >= 0) {
+    want.insert(next);
+  }
+  if (auto prev = osdmap->get_previous_up_osd_before(whoami); prev >= 0) {
+    want.insert(prev);
+  }
+  // make sure we have at least **min_down** osds coming from different
+  // subtree level (e.g., hosts) for fast failure detection.
+  auto min_down = local_conf().get_val<uint64_t>("mon_osd_min_down_reporters");
+  auto subtree = local_conf().get_val<string>("mon_osd_reporter_subtree_level");
+  osdmap->get_random_up_osds_by_subtree(
+    whoami, subtree, min_down, want, &want);
+  for (auto osd : want) {
+    add_peer(osd, osdmap->get_epoch());
+  }
+}
+
+seastar::future<> Heartbeat::update_peers(int whoami)
+{
+  const auto min_peers = static_cast<size_t>(
+    local_conf().get_val<int64_t>("osd_heartbeat_min_peers"));
+  return remove_down_peers().then([=](osds_t&& extra) {
+    add_reporter_peers(whoami);
+    // too many?
+    struct iteration_state {
+      osds_t::const_iterator where;
+      osds_t::const_iterator end;
+    };
+    return seastar::do_with(iteration_state{extra.begin(),extra.end()},
+      [=](iteration_state& s) {
+        return seastar::do_until(
+          [min_peers, &s, this] {
+            return peers.size() < min_peers || s.where == s.end; },
+          [&s, this] {
+            return remove_peer(*s.where); }
+        );
+    });
+  }).then([=] {
+    // or too few?
+    auto osdmap = service.get_map();
+    for (auto next = osdmap->get_next_up_osd_after(whoami);
+      peers.size() < min_peers && next >= 0 && next != whoami;
+      next = osdmap->get_next_up_osd_after(next)) {
+      add_peer(next, osdmap->get_epoch());
+    }
+    return seastar::now();
+  });
+}
+
+seastar::future<> Heartbeat::remove_peer(osd_id_t peer)
+{
+  auto found = peers.find(peer);
+  assert(found != peers.end());
+  logger().info("remove_peer({})", peer);
+  return seastar::when_all_succeed(found->second.con_front->close(),
+                                   found->second.con_back->close()).then(
+    [this, peer] {
+      peers.erase(peer);
+      return seastar::now();
+    });
+}
+
+seastar::future<> Heartbeat::ms_dispatch(ceph::net::ConnectionRef conn,
+                                         MessageRef m)
+{
+  logger().info("heartbeat: ms_dispatch {} from {}",
+                *m, m->get_source());
+  switch (m->get_type()) {
+  case CEPH_MSG_PING:
+    return handle_osd_ping(conn, boost::static_pointer_cast<MOSDPing>(m));
+  default:
+    return seastar::now();
+  }
+}
+
+seastar::future<> Heartbeat::handle_osd_ping(ceph::net::ConnectionRef conn,
+                                             Ref<MOSDPing> m)
+{
+  switch (m->op) {
+  case MOSDPing::PING:
+    return handle_ping(conn, m);
+  case MOSDPing::PING_REPLY:
+    return handle_reply(conn, m);
+  case MOSDPing::YOU_DIED:
+    return handle_you_died();
+  default:
+    return seastar::now();
+  }
+}
+
+seastar::future<> Heartbeat::handle_ping(ceph::net::ConnectionRef conn,
+                                         Ref<MOSDPing> m)
+{
+  auto min_message = static_cast<uint32_t>(
+    local_conf()->osd_heartbeat_min_size);
+  auto reply =
+    make_message<MOSDPing>(m->fsid,
+                           service.get_map()->get_epoch(),
+                           MOSDPing::PING_REPLY,
+                           m->stamp,
+                           min_message);
+  return conn->send(reply);
+}
+
+seastar::future<> Heartbeat::handle_reply(ceph::net::ConnectionRef conn,
+                                          Ref<MOSDPing> m)
+{
+  const osd_id_t from = m->get_source().num();
+  auto found = peers.find(from);
+  if (found == peers.end()) {
+    // stale reply
+    return seastar::now();
+  }
+  auto& peer = found->second;
+  auto ping = peer.ping_history.find(m->stamp);
+  if (ping == peer.ping_history.end()) {
+    // old replies, deprecated by newly sent pings.
+    return seastar::now();
+  }
+  const auto now = clock::now();
+  auto& unacked = ping->second.unacknowledged;
+  if (conn == peer.con_back) {
+    peer.last_rx_back = now;
+    unacked--;
+  } else if (conn == peer.con_front) {
+    peer.last_rx_front = now;
+    unacked--;
+  }
+  if (unacked == 0) {
+    peer.ping_history.erase(peer.ping_history.begin(), ++ping);
+  }
+  if (peer.is_healthy(now)) {
+    // cancel false reports
+    failure_queue.erase(from);
+    if (auto pending = failure_pending.find(from);
+        pending != failure_pending.end()) {
+      return send_still_alive(from, pending->second.addrs);
+    }
+  }
+  return seastar::now();
+}
+
+seastar::future<> Heartbeat::handle_you_died()
+{
+  // TODO: ask for newer osdmap
+  return seastar::now();
+}
+
+seastar::future<> Heartbeat::send_heartbeats()
+{
+  using peers_item_t = typename peers_map_t::value_type;
+  return seastar::parallel_for_each(peers,
+    [this](peers_item_t& item) {
+      const auto now = clock::now();
+      const auto deadline =
+        now + std::chrono::seconds(local_conf()->osd_heartbeat_grace);
+      auto& [peer, info] = item;
+      info.last_tx = now;
+      if (clock::is_zero(info.first_tx)) {
+        info.first_tx = now;
+      }
+      const utime_t sent_stamp{now};
+      auto [reply, added] = info.ping_history.emplace(sent_stamp,
+                                                      reply_t{deadline, 0});
+      std::vector<ceph::net::ConnectionRef> conns{info.con_front,
+                                                  info.con_back};
+      return seastar::parallel_for_each(std::move(conns),
+        [sent_stamp, &reply=reply->second, this] (auto con) {
+          if (con) {
+            auto min_message = static_cast<uint32_t>(
+              local_conf()->osd_heartbeat_min_size);
+            auto ping = make_message<MOSDPing>(monc.get_fsid(),
+                                               service.get_map()->get_epoch(),
+                                               MOSDPing::PING,
+                                               sent_stamp,
+                                               min_message);
+            return con->send(ping).then([&reply] {
+              reply.unacknowledged++;
+              return seastar::now();
+            });
+          } else {
+            return seastar::now();
+          }
+        });
+    });
+}
+
+seastar::future<> Heartbeat::send_failures()
+{
+  using failure_item_t = typename failure_queue_t::value_type;
+  return seastar::parallel_for_each(failure_queue,
+    [this](failure_item_t& failure_item) {
+      auto [osd, failed_since] = failure_item;
+      if (failure_pending.count(osd)) {
+        return seastar::now();
+      }
+      auto failed_for = chrono::duration_cast<chrono::seconds>(
+        clock::now() - failed_since).count();
+      auto osdmap = service.get_map();
+      auto failure_report =
+        make_message<MOSDFailure>(monc.get_fsid(),
+                                  osd,
+                                  osdmap->get_addrs(osd),
+                                  static_cast<int>(failed_for),
+                                  osdmap->get_epoch());
+      failure_pending.emplace(osd, failure_info_t{failed_since,
+                                                  osdmap->get_addrs(osd)});
+      return monc.send_message(failure_report);
+    }).then([this] {
+      failure_queue.clear();
+      return seastar::now();
+    });
+}
+
+seastar::future<> Heartbeat::send_still_alive(osd_id_t osd,
+                                              const entity_addrvec_t& addrs)
+{
+  auto still_alive = make_message<MOSDFailure>(monc.get_fsid(),
+                                               osd,
+                                               addrs,
+                                               0,
+                                               service.get_map()->get_epoch(),
+                                               MOSDFailure::FLAG_ALIVE);
+  return monc.send_message(still_alive).then([=] {
+    failure_pending.erase(osd);
+    return seastar::now();
+  });
+}
+
+bool Heartbeat::PeerInfo::is_unhealthy(clock::time_point now) const
+{
+  if (ping_history.empty()) {
+    // we haven't sent a ping yet or we have got all replies,
+    // in either way we are safe and healthy for now
+    return false;
+  } else {
+    auto oldest_ping = ping_history.begin();
+    return now > oldest_ping->second.deadline;
+  }
+}
+
+bool Heartbeat::PeerInfo::is_healthy(clock::time_point now) const
+{
+  if (con_front && clock::is_zero(last_rx_front)) {
+    return false;
+  }
+  if (con_back && clock::is_zero(last_rx_back)) {
+    return false;
+  }
+  // only declare to be healthy until we have received the first
+  // replies from both front/back connections
+  return !is_unhealthy(now);
+}
diff --git a/src/crimson/osd/heartbeat.h b/src/crimson/osd/heartbeat.h
new file mode 100644
index 00000000..b5eb0f7c
--- /dev/null
+++ b/src/crimson/osd/heartbeat.h
@@ -0,0 +1,121 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <cstdint>
+#include <seastar/core/future.hh>
+#include "common/ceph_time.h"
+#include "crimson/net/Dispatcher.h"
+#include "crimson/net/Fwd.h"
+
+class MOSDPing;
+class OSDMapService;
+
+namespace ceph::mon {
+  class Client;
+}
+
+template<typename Message> using Ref = boost::intrusive_ptr<Message>;
+
+class Heartbeat : public ceph::net::Dispatcher {
+public:
+  using osd_id_t = int;
+
+  Heartbeat(int whoami,
+	    uint32_t nonce,
+	    const OSDMapService& service,
+	    ceph::mon::Client& monc);
+
+  seastar::future<> start(entity_addrvec_t front,
+			  entity_addrvec_t back);
+  seastar::future<> stop();
+
+  seastar::future<> add_peer(osd_id_t peer, epoch_t epoch);
+  seastar::future<> update_peers(int whoami);
+  seastar::future<> remove_peer(osd_id_t peer);
+
+  seastar::future<> send_heartbeats();
+  seastar::future<> send_failures();
+
+  const entity_addrvec_t& get_front_addrs() const;
+  const entity_addrvec_t& get_back_addrs() const;
+
+  // Dispatcher methods
+  seastar::future<> ms_dispatch(ceph::net::ConnectionRef conn,
+				MessageRef m) override;
+
+private:
+  seastar::future<> handle_osd_ping(ceph::net::ConnectionRef conn,
+				    Ref<MOSDPing> m);
+  seastar::future<> handle_ping(ceph::net::ConnectionRef conn,
+				Ref<MOSDPing> m);
+  seastar::future<> handle_reply(ceph::net::ConnectionRef conn,
+				 Ref<MOSDPing> m);
+  seastar::future<> handle_you_died();
+
+  seastar::future<> send_still_alive(osd_id_t, const entity_addrvec_t&);
+
+  using osds_t = std::vector<osd_id_t>;
+  /// remove down OSDs
+  /// @return peers not needed in this epoch
+  seastar::future<osds_t> remove_down_peers();
+  /// add enough reporters for fast failure detection
+  void add_reporter_peers(int whoami);
+
+  seastar::future<> start_messenger(ceph::net::Messenger* msgr,
+				    const entity_addrvec_t& addrs);
+private:
+  const int whoami;
+  const uint32_t nonce;
+  ceph::net::Messenger* front_msgr = nullptr;
+  ceph::net::Messenger* back_msgr = nullptr;
+  const OSDMapService& service;
+  ceph::mon::Client& monc;
+
+  seastar::timer<seastar::lowres_clock> timer;
+  // use real_clock so it can be converted to utime_t
+  using clock = ceph::coarse_real_clock;
+
+  struct reply_t {
+    clock::time_point deadline;
+    // one sent over front conn, another sent over back conn
+    uint8_t unacknowledged = 0;
+  };
+  struct PeerInfo {
+    /// peer connection (front)
+    ceph::net::ConnectionRef con_front;
+    /// peer connection (back)
+    ceph::net::ConnectionRef con_back;
+    /// time we sent our first ping request
+    clock::time_point first_tx;
+    /// last time we sent a ping request
+    clock::time_point last_tx;
+    /// last time we got a ping reply on the front side
+    clock::time_point last_rx_front;
+    /// last time we got a ping reply on the back side
+    clock::time_point last_rx_back;
+    /// most recent epoch we wanted this peer
+    epoch_t epoch;
+    /// history of inflight pings, arranging by timestamp we sent
+    std::map<utime_t, reply_t> ping_history;
+
+    bool is_unhealthy(clock::time_point now) const;
+    bool is_healthy(clock::time_point now) const;
+  };
+  using peers_map_t = std::map<osd_id_t, PeerInfo>;
+  peers_map_t peers;
+
+  // osds which are considered failed
+  // osd_id => when was the last time that both front and back pings were acked
+  //           use for calculating how long the OSD has been unresponsive
+  using failure_queue_t = std::map<osd_id_t, clock::time_point>;
+  failure_queue_t failure_queue;
+  struct failure_info_t {
+    clock::time_point failed_since;
+    entity_addrvec_t addrs;
+  };
+  // osds we've reported to monior as failed ones, but they are not marked down
+  // yet
+  std::map<osd_id_t, failure_info_t> failure_pending;
+};
diff --git a/src/crimson/osd/main.cc b/src/crimson/osd/main.cc
new file mode 100644
index 00000000..04a0c97d
--- /dev/null
+++ b/src/crimson/osd/main.cc
@@ -0,0 +1,89 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
+// vim: ts=8 sw=2 smarttab
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <iostream>
+
+#include <seastar/core/app-template.hh>
+#include <seastar/core/thread.hh>
+
+#include "common/ceph_argparse.h"
+#include "crimson/common/config_proxy.h"
+
+#include "osd.h"
+
+using config_t = ceph::common::ConfigProxy;
+
+void usage(const char* prog) {
+  std::cout << "usage: " << prog << " -i <ID>" << std::endl;
+  generic_server_usage();
+}
+
+int main(int argc, char* argv[])
+{
+  std::vector<const char*> args{argv + 1, argv + argc};
+  if (ceph_argparse_need_usage(args)) {
+    usage(argv[0]);
+    return EXIT_SUCCESS;
+  }
+  std::string cluster;
+  std::string conf_file_list;
+  // ceph_argparse_early_args() could _exit(), while local_conf() won't ready
+  // until it's started. so do the boilerplate-settings parsing here.
+  auto init_params = ceph_argparse_early_args(args,
+                                              CEPH_ENTITY_TYPE_OSD,
+                                              &cluster,
+                                              &conf_file_list);
+  seastar::app_template app;
+  app.add_options()
+    ("mkfs", "create a [new] data directory");
+  seastar::sharded<OSD> osd;
+
+  using ceph::common::sharded_conf;
+  using ceph::common::sharded_perf_coll;
+  using ceph::common::local_conf;
+
+  args.insert(begin(args), argv[0]);
+  try {
+    return app.run_deprecated(args.size(), const_cast<char**>(args.data()), [&] {
+      auto& config = app.configuration();
+      seastar::engine().at_exit([] {
+        return sharded_conf().stop();
+      });
+      seastar::engine().at_exit([] {
+        return sharded_perf_coll().stop();
+      });
+      seastar::engine().at_exit([&] {
+       return osd.stop();
+      });
+      return sharded_conf().start(init_params.name, cluster).then([] {
+        return sharded_perf_coll().start();
+      }).then([&conf_file_list] {
+        return local_conf().parse_config_files(conf_file_list);
+      }).then([&] {
+        return osd.start_single(std::stoi(local_conf()->name.get_id()),
+                                static_cast<uint32_t>(getpid()));
+      }).then([&osd, mkfs = config.count("mkfs")] {
+        if (mkfs) {
+          return osd.invoke_on(0, &OSD::mkfs,
+                               local_conf().get_val<uuid_d>("fsid"));
+        } else {
+          return osd.invoke_on(0, &OSD::start);
+        }
+      });
+    });
+  } catch (...) {
+    seastar::fprint(std::cerr, "FATAL: Exception during startup, aborting: %s\n", std::current_exception());
+    return EXIT_FAILURE;
+  }
+}
+
+/*
+ * Local Variables:
+ * compile-command: "make -j4 \
+ * -C ../../../build \
+ * crimson-osd"
+ * End:
+ */
diff --git a/src/crimson/osd/osd.cc b/src/crimson/osd/osd.cc
new file mode 100644
index 00000000..bdb1642e
--- /dev/null
+++ b/src/crimson/osd/osd.cc
@@ -0,0 +1,658 @@
+#include "osd.h"
+
+#include <boost/range/join.hpp>
+#include <boost/smart_ptr/make_local_shared.hpp>
+
+#include "common/pick_address.h"
+#include "messages/MOSDBeacon.h"
+#include "messages/MOSDBoot.h"
+#include "messages/MOSDMap.h"
+#include "crimson/net/Connection.h"
+#include "crimson/net/Messenger.h"
+#include "crimson/os/cyan_collection.h"
+#include "crimson/os/cyan_object.h"
+#include "crimson/os/cyan_store.h"
+#include "crimson/os/Transaction.h"
+#include "crimson/osd/heartbeat.h"
+#include "crimson/osd/osd_meta.h"
+#include "crimson/osd/pg.h"
+#include "crimson/osd/pg_meta.h"
+
+namespace {
+  seastar::logger& logger() {
+    return ceph::get_logger(ceph_subsys_osd);
+  }
+
+  template<typename Message, typename... Args>
+  Ref<Message> make_message(Args&&... args)
+  {
+    return {new Message{std::forward<Args>(args)...}, false};
+  }
+  static constexpr int TICK_INTERVAL = 1;
+}
+
+using ceph::common::local_conf;
+using ceph::os::CyanStore;
+
+OSD::OSD(int id, uint32_t nonce)
+  : whoami{id},
+    nonce{nonce},
+    beacon_timer{[this] { send_beacon(); }},
+    heartbeat_timer{[this] { update_heartbeat_peers(); }}
+{
+  osdmaps[0] = boost::make_local_shared<OSDMap>();
+}
+
+OSD::~OSD() = default;
+
+namespace {
+// Initial features in new superblock.
+// Features here are also automatically upgraded
+CompatSet get_osd_initial_compat_set()
+{
+  CompatSet::FeatureSet ceph_osd_feature_compat;
+  CompatSet::FeatureSet ceph_osd_feature_ro_compat;
+  CompatSet::FeatureSet ceph_osd_feature_incompat;
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_BASE);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_PGINFO);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_OLOC);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_LEC);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_CATEGORIES);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_HOBJECTPOOL);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_BIGINFO);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_LEVELDBINFO);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_LEVELDBLOG);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_SNAPMAPPER);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_HINTS);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_PGMETA);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_MISSING);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_FASTINFO);
+  ceph_osd_feature_incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_RECOVERY_DELETES);
+  return CompatSet(ceph_osd_feature_compat,
+                   ceph_osd_feature_ro_compat,
+                   ceph_osd_feature_incompat);
+}
+}
+
+seastar::future<> OSD::mkfs(uuid_d cluster_fsid)
+{
+  const auto data_path = local_conf().get_val<std::string>("osd_data");
+  store = std::make_unique<ceph::os::CyanStore>(data_path);
+  uuid_d osd_fsid;
+  osd_fsid.generate_random();
+  return store->mkfs(osd_fsid).then([this] {
+    return store->mount();
+  }).then([cluster_fsid, osd_fsid, this] {
+    superblock.cluster_fsid = cluster_fsid;
+    superblock.osd_fsid = osd_fsid;
+    superblock.whoami = whoami;
+    superblock.compat_features = get_osd_initial_compat_set();
+
+    meta_coll = make_unique<OSDMeta>(
+      store->create_new_collection(coll_t::meta()), store.get());
+    ceph::os::Transaction t;
+    meta_coll->create(t);
+    meta_coll->store_superblock(t, superblock);
+    return store->do_transaction(meta_coll->collection(), std::move(t));
+  }).then([cluster_fsid, this] {
+    store->write_meta("ceph_fsid", cluster_fsid.to_string());
+    store->write_meta("whoami", std::to_string(whoami));
+    return seastar::now();
+  });
+}
+
+namespace {
+  entity_addrvec_t pick_addresses(int what) {
+    entity_addrvec_t addrs;
+    CephContext cct;
+    if (int r = ::pick_addresses(&cct, what, &addrs, -1); r < 0) {
+      throw std::runtime_error("failed to pick address");
+    }
+    // TODO: v2: ::pick_addresses() returns v2 addresses, but crimson-msgr does
+    // not support v2 yet. remove following set_type() once v2 support is ready.
+    for (auto addr : addrs.v) {
+      addr.set_type(addr.TYPE_LEGACY);
+      logger().info("picked address {}", addr);
+    }
+    return addrs;
+  }
+  std::pair<entity_addrvec_t, bool>
+  replace_unknown_addrs(entity_addrvec_t maybe_unknowns,
+                        const entity_addrvec_t& knowns) {
+    bool changed = false;
+    auto maybe_replace = [&](entity_addr_t addr) {
+      if (!addr.is_blank_ip()) {
+        return addr;
+      }
+      for (auto& b : knowns.v) {
+        if (addr.get_family() == b.get_family()) {
+          auto a = b;
+          a.set_nonce(addr.get_nonce());
+          a.set_type(addr.get_type());
+          a.set_port(addr.get_port());
+          changed = true;
+          return a;
+        }
+      }
+      throw std::runtime_error("failed to replace unknown address");
+    };
+    entity_addrvec_t replaced;
+    std::transform(maybe_unknowns.v.begin(),
+                   maybe_unknowns.v.end(),
+                   std::back_inserter(replaced.v),
+                   maybe_replace);
+    return {replaced, changed};
+  }
+}
+
+seastar::future<> OSD::start()
+{
+  logger().info("start");
+
+  return seastar::when_all_succeed(
+    ceph::net::Messenger::create(entity_name_t::OSD(whoami),
+                                 "cluster",
+                                 nonce,
+                                 seastar::engine().cpu_id())
+      .then([this] (auto msgr) { cluster_msgr = msgr; }),
+    ceph::net::Messenger::create(entity_name_t::OSD(whoami),
+                                 "client",
+                                 nonce,
+                                 seastar::engine().cpu_id())
+      .then([this] (auto msgr) { public_msgr = msgr; }))
+  .then([this] {
+    monc.reset(new ceph::mon::Client{*public_msgr});
+    heartbeat.reset(new Heartbeat{whoami, nonce, *this, *monc});
+
+    for (auto msgr : {cluster_msgr, public_msgr}) {
+      if (local_conf()->ms_crc_data) {
+        msgr->set_crc_data();
+      }
+      if (local_conf()->ms_crc_header) {
+        msgr->set_crc_header();
+      }
+    }
+    dispatchers.push_front(this);
+    dispatchers.push_front(monc.get());
+
+    const auto data_path = local_conf().get_val<std::string>("osd_data");
+    store = std::make_unique<ceph::os::CyanStore>(data_path);
+    return store->mount();
+  }).then([this] {
+    meta_coll = make_unique<OSDMeta>(store->open_collection(coll_t::meta()),
+                                     store.get());
+    return meta_coll->load_superblock();
+  }).then([this](OSDSuperblock&& sb) {
+    superblock = std::move(sb);
+    return get_map(superblock.current_epoch);
+  }).then([this](cached_map_t&& map) {
+    osdmap = std::move(map);
+    return load_pgs();
+  }).then([this] {
+    return seastar::when_all_succeed(
+      cluster_msgr->try_bind(pick_addresses(CEPH_PICK_ADDRESS_CLUSTER),
+                             local_conf()->ms_bind_port_min,
+                             local_conf()->ms_bind_port_max)
+        .then([this] { return cluster_msgr->start(&dispatchers); }),
+      public_msgr->try_bind(pick_addresses(CEPH_PICK_ADDRESS_PUBLIC),
+                            local_conf()->ms_bind_port_min,
+                            local_conf()->ms_bind_port_max)
+        .then([this] { return public_msgr->start(&dispatchers); }));
+  }).then([this] {
+    return monc->start();
+  }).then([this] {
+    monc->sub_want("osd_pg_creates", last_pg_create_epoch, 0);
+    monc->sub_want("mgrmap", 0, 0);
+    monc->sub_want("osdmap", 0, 0);
+    return monc->renew_subs();
+  }).then([this] {
+    if (auto [addrs, changed] =
+        replace_unknown_addrs(cluster_msgr->get_myaddrs(),
+                              public_msgr->get_myaddrs()); changed) {
+      cluster_msgr->set_myaddrs(addrs);
+    }
+    return heartbeat->start(public_msgr->get_myaddrs(),
+                            cluster_msgr->get_myaddrs());
+  }).then([this] {
+    return start_boot();
+  });
+}
+
+seastar::future<> OSD::start_boot()
+{
+  state.set_preboot();
+  return monc->get_version("osdmap").then([this](version_t newest, version_t oldest) {
+    return _preboot(oldest, newest);
+  });
+}
+
+seastar::future<> OSD::_preboot(version_t oldest, version_t newest)
+{
+  logger().info("osd.{}: _preboot", whoami);
+  if (osdmap->get_epoch() == 0) {
+    logger().warn("waiting for initial osdmap");
+  } else if (osdmap->is_destroyed(whoami)) {
+    logger().warn("osdmap says I am destroyed");
+    // provide a small margin so we don't livelock seeing if we
+    // un-destroyed ourselves.
+    if (osdmap->get_epoch() > newest - 1) {
+      throw std::runtime_error("i am destroyed");
+    }
+  } else if (osdmap->is_noup(whoami)) {
+    logger().warn("osdmap NOUP flag is set, waiting for it to clear");
+  } else if (!osdmap->test_flag(CEPH_OSDMAP_SORTBITWISE)) {
+    logger().error("osdmap SORTBITWISE OSDMap flag is NOT set; please set it");
+  } else if (osdmap->require_osd_release < CEPH_RELEASE_LUMINOUS) {
+    logger().error("osdmap require_osd_release < luminous; please upgrade to luminous");
+  } else if (false) {
+    // TODO: update mon if current fullness state is different from osdmap
+  } else if (version_t n = local_conf()->osd_map_message_max;
+             osdmap->get_epoch() >= oldest - 1 &&
+             osdmap->get_epoch() + n > newest) {
+    return _send_boot();
+  }
+  // get all the latest maps
+  if (osdmap->get_epoch() + 1 >= oldest) {
+    return osdmap_subscribe(osdmap->get_epoch() + 1, false);
+  } else {
+    return osdmap_subscribe(oldest - 1, true);
+  }
+}
+
+seastar::future<> OSD::_send_boot()
+{
+  state.set_booting();
+
+  logger().info("hb_back_msgr: {}", heartbeat->get_back_addrs());
+  logger().info("hb_front_msgr: {}", heartbeat->get_front_addrs());
+  logger().info("cluster_msgr: {}", cluster_msgr->get_myaddr());
+  auto m = make_message<MOSDBoot>(superblock,
+                                  osdmap->get_epoch(),
+                                  osdmap->get_epoch(),
+                                  heartbeat->get_back_addrs(),
+                                  heartbeat->get_front_addrs(),
+                                  cluster_msgr->get_myaddrs(),
+                                  CEPH_FEATURES_ALL);
+  return monc->send_message(m);
+}
+
+seastar::future<> OSD::stop()
+{
+  // see also OSD::shutdown()
+  state.set_stopping();
+  return gate.close().then([this] {
+    return heartbeat->stop();
+  }).then([this] {
+    return monc->stop();
+  }).then([this] {
+    return public_msgr->shutdown();
+  }).then([this] {
+    return cluster_msgr->shutdown();
+  });
+}
+
+seastar::future<> OSD::load_pgs()
+{
+  return seastar::parallel_for_each(store->list_collections(),
+    [this](auto coll) {
+      spg_t pgid;
+      if (coll.is_pg(&pgid)) {
+        return load_pg(pgid).then([pgid, this](auto&& pg) {
+          logger().info("load_pgs: loaded {}", pgid);
+          pgs.emplace(pgid, std::move(pg));
+          return seastar::now();
+        });
+      } else if (coll.is_temp(&pgid)) {
+        // TODO: remove the collection
+        return seastar::now();
+      } else {
+        logger().warn("ignoring unrecognized collection: {}", coll);
+        return seastar::now();
+      }
+    });
+}
+
+seastar::future<Ref<PG>> OSD::load_pg(spg_t pgid)
+{
+  using ec_profile_t = map<string,string>;
+  return PGMeta{store.get(), pgid}.get_epoch().then([this](epoch_t e) {
+    return get_map(e);
+  }).then([pgid, this] (auto&& create_map) {
+    if (create_map->have_pg_pool(pgid.pool())) {
+      pg_pool_t pi = *create_map->get_pg_pool(pgid.pool());
+      string name = create_map->get_pool_name(pgid.pool());
+      ec_profile_t ec_profile;
+      if (pi.is_erasure()) {
+        ec_profile = create_map->get_erasure_code_profile(pi.erasure_code_profile);
+      }
+      return seastar::make_ready_future<pg_pool_t,
+                                        string,
+                                        ec_profile_t>(std::move(pi),
+                                                      std::move(name),
+                                                      std::move(ec_profile));
+    } else {
+      // pool was deleted; grab final pg_pool_t off disk.
+      return meta_coll->load_final_pool_info(pgid.pool());
+    }
+  }).then([this](pg_pool_t&& pool, string&& name, ec_profile_t&& ec_profile) {
+    Ref<PG> pg{new PG{std::move(pool),
+                      std::move(name),
+                      std::move(ec_profile)}};
+    return seastar::make_ready_future<Ref<PG>>(std::move(pg));
+  });
+}
+
+seastar::future<> OSD::ms_dispatch(ceph::net::ConnectionRef conn, MessageRef m)
+{
+  logger().info("ms_dispatch {}", *m);
+  if (state.is_stopping()) {
+    return seastar::now();
+  }
+
+  switch (m->get_type()) {
+  case CEPH_MSG_OSD_MAP:
+    return handle_osd_map(conn, boost::static_pointer_cast<MOSDMap>(m));
+  default:
+    return seastar::now();
+  }
+}
+
+seastar::future<> OSD::ms_handle_connect(ceph::net::ConnectionRef conn)
+{
+  if (conn->get_peer_type() != CEPH_ENTITY_TYPE_MON) {
+    return seastar::now();
+  } else {
+    return seastar::now();
+  }
+}
+
+seastar::future<> OSD::ms_handle_reset(ceph::net::ConnectionRef conn)
+{
+  // TODO: cleanup the session attached to this connection
+  logger().warn("ms_handle_reset");
+  return seastar::now();
+}
+
+seastar::future<> OSD::ms_handle_remote_reset(ceph::net::ConnectionRef conn)
+{
+  logger().warn("ms_handle_remote_reset");
+  return seastar::now();
+}
+
+OSD::cached_map_t OSD::get_map() const
+{
+  return osdmap;
+}
+
+seastar::future<OSD::cached_map_t> OSD::get_map(epoch_t e)
+{
+  // TODO: use LRU cache for managing osdmap, fallback to disk if we have to
+  if (auto found = osdmaps.find(e); found) {
+    return seastar::make_ready_future<cached_map_t>(std::move(found));
+  } else {
+    return load_map_bl(e).then([e, this](bufferlist bl) {
+      auto osdmap = std::make_unique<OSDMap>();
+      osdmap->decode(bl);
+      return seastar::make_ready_future<cached_map_t>(
+        osdmaps.insert(e, std::move(osdmap)));
+    });
+  }
+}
+
+void OSD::store_map_bl(ceph::os::Transaction& t,
+                       epoch_t e, bufferlist&& bl)
+{
+  meta_coll->store_map(t, e, bl);
+  map_bl_cache.insert(e, std::move(bl));
+}
+
+seastar::future<bufferlist> OSD::load_map_bl(epoch_t e)
+{
+  if (std::optional<bufferlist> found = map_bl_cache.find(e); found) {
+    return seastar::make_ready_future<bufferlist>(*found);
+  } else {
+    return meta_coll->load_map(e);
+  }
+}
+
+seastar::future<> OSD::store_maps(ceph::os::Transaction& t,
+                                  epoch_t start, Ref<MOSDMap> m)
+{
+  return seastar::do_for_each(boost::counting_iterator<epoch_t>(start),
+                              boost::counting_iterator<epoch_t>(m->get_last() + 1),
+                              [&t, m, this](epoch_t e) {
+    if (auto p = m->maps.find(e); p != m->maps.end()) {
+      auto o = std::make_unique<OSDMap>();
+      o->decode(p->second);
+      logger().info("store_maps osdmap.{}", e);
+      store_map_bl(t, e, std::move(std::move(p->second)));
+      osdmaps.insert(e, std::move(o));
+      return seastar::now();
+    } else if (auto p = m->incremental_maps.find(e);
+               p != m->incremental_maps.end()) {
+      OSDMap::Incremental inc;
+      auto i = p->second.cbegin();
+      inc.decode(i);
+      return load_map_bl(e - 1)
+        .then([&t, e, inc=std::move(inc), this](bufferlist bl) {
+          auto o = std::make_unique<OSDMap>();
+          o->decode(bl);
+          o->apply_incremental(inc);
+          bufferlist fbl;
+          o->encode(fbl, inc.encode_features | CEPH_FEATURE_RESERVED);
+          store_map_bl(t, e, std::move(fbl));
+          osdmaps.insert(e, std::move(o));
+          return seastar::now();
+      });
+    } else {
+      logger().error("MOSDMap lied about what maps it had?");
+      return seastar::now();
+    }
+  });
+}
+
+seastar::future<> OSD::osdmap_subscribe(version_t epoch, bool force_request)
+{
+  logger().info("{}({})", __func__, epoch);
+  if (monc->sub_want_increment("osdmap", epoch, CEPH_SUBSCRIBE_ONETIME) ||
+      force_request) {
+    return monc->renew_subs();
+  } else {
+    return seastar::now();
+  }
+}
+
+seastar::future<> OSD::handle_osd_map(ceph::net::ConnectionRef conn,
+                                      Ref<MOSDMap> m)
+{
+  logger().info("handle_osd_map {}", *m);
+  if (m->fsid != superblock.cluster_fsid) {
+    logger().warn("fsid mismatched");
+    return seastar::now();
+  }
+  if (state.is_initializing()) {
+    logger().warn("i am still initializing");
+    return seastar::now();
+  }
+
+  const auto first = m->get_first();
+  const auto last = m->get_last();
+
+  // make sure there is something new, here, before we bother flushing
+  // the queues and such
+  if (last <= superblock.newest_map) {
+    return seastar::now();
+  }
+  // missing some?
+  bool skip_maps = false;
+  epoch_t start = superblock.newest_map + 1;
+  if (first > start) {
+    logger().info("handle_osd_map message skips epochs {}..{}",
+                  start, first - 1);
+    if (m->oldest_map <= start) {
+      return osdmap_subscribe(start, false);
+    }
+    // always try to get the full range of maps--as many as we can.  this
+    //  1- is good to have
+    //  2- is at present the only way to ensure that we get a *full* map as
+    //     the first map!
+    if (m->oldest_map < first) {
+      return osdmap_subscribe(m->oldest_map - 1, true);
+    }
+    skip_maps = true;
+    start = first;
+  }
+
+  return seastar::do_with(ceph::os::Transaction{},
+                          [=](auto& t) {
+    return store_maps(t, start, m).then([=, &t] {
+      // even if this map isn't from a mon, we may have satisfied our subscription
+      monc->sub_got("osdmap", last);
+      if (!superblock.oldest_map || skip_maps) {
+        superblock.oldest_map = first;
+      }
+      superblock.newest_map = last;
+      superblock.current_epoch = last;
+
+      // note in the superblock that we were clean thru the prior epoch
+      if (boot_epoch && boot_epoch >= superblock.mounted) {
+        superblock.mounted = boot_epoch;
+        superblock.clean_thru = last;
+      }
+      meta_coll->store_superblock(t, superblock);
+      return store->do_transaction(meta_coll->collection(), std::move(t));
+    });
+  }).then([=] {
+    // TODO: write to superblock and commit the transaction
+    return committed_osd_maps(start, last, m);
+  });
+}
+
+seastar::future<> OSD::committed_osd_maps(version_t first,
+                                          version_t last,
+                                          Ref<MOSDMap> m)
+{
+  logger().info("osd.{}: committed_osd_maps({}, {})", whoami, first, last);
+  // advance through the new maps
+  return seastar::parallel_for_each(boost::irange(first, last + 1),
+                                    [this](epoch_t cur) {
+    return get_map(cur).then([this](cached_map_t&& o) {
+      osdmap = std::move(o);
+      if (up_epoch != 0 &&
+          osdmap->is_up(whoami) &&
+          osdmap->get_addrs(whoami) == public_msgr->get_myaddrs()) {
+        up_epoch = osdmap->get_epoch();
+        if (!boot_epoch) {
+          boot_epoch = osdmap->get_epoch();
+        }
+      }
+    });
+  }).then([m, this] {
+    if (osdmap->is_up(whoami) &&
+        osdmap->get_addrs(whoami) == public_msgr->get_myaddrs() &&
+        bind_epoch < osdmap->get_up_from(whoami)) {
+      if (state.is_booting()) {
+        logger().info("osd.{}: activating...", whoami);
+        state.set_active();
+        beacon_timer.arm_periodic(
+          std::chrono::seconds(local_conf()->osd_beacon_report_interval));
+        heartbeat_timer.arm_periodic(
+          std::chrono::seconds(TICK_INTERVAL));
+      }
+    }
+
+    if (state.is_active()) {
+      logger().info("osd.{}: now active", whoami);
+      if (!osdmap->exists(whoami)) {
+        return shutdown();
+      }
+      if (should_restart()) {
+        return restart();
+      } else {
+        return seastar::now();
+      }
+    } else if (state.is_preboot()) {
+      logger().info("osd.{}: now preboot", whoami);
+
+      if (m->get_source().is_mon()) {
+        return _preboot(m->oldest_map, m->newest_map);
+      } else {
+        logger().info("osd.{}: start_boot", whoami);
+        return start_boot();
+      }
+    } else {
+      logger().info("osd.{}: now {}", whoami, state);
+      // XXX
+      return seastar::now();
+    }
+  });
+}
+
+bool OSD::should_restart() const
+{
+  if (!osdmap->is_up(whoami)) {
+    logger().info("map e {} marked osd.{} down",
+                  osdmap->get_epoch(), whoami);
+    return true;
+  } else if (osdmap->get_addrs(whoami) != public_msgr->get_myaddrs()) {
+    logger().error("map e {} had wrong client addr ({} != my {})",
+                   osdmap->get_epoch(),
+                   osdmap->get_addrs(whoami),
+                   public_msgr->get_myaddrs());
+    return true;
+  } else if (osdmap->get_cluster_addrs(whoami) != cluster_msgr->get_myaddrs()) {
+    logger().error("map e {} had wrong cluster addr ({} != my {})",
+                   osdmap->get_epoch(),
+                   osdmap->get_cluster_addrs(whoami),
+                   cluster_msgr->get_myaddrs());
+    return true;
+  } else {
+    return false;
+  }
+}
+
+seastar::future<> OSD::restart()
+{
+  up_epoch = 0;
+  bind_epoch = osdmap->get_epoch();
+  // TODO: promote to shutdown if being marked down for multiple times
+  // rebind messengers
+  return start_boot();
+}
+
+seastar::future<> OSD::shutdown()
+{
+  // TODO
+  superblock.mounted = boot_epoch;
+  superblock.clean_thru = osdmap->get_epoch();
+  return seastar::now();
+}
+
+seastar::future<> OSD::send_beacon()
+{
+  // FIXME: min lec should be calculated from pg_stat
+  //        and should set m->pgs
+  epoch_t min_last_epoch_clean = osdmap->get_epoch();
+  auto m = make_message<MOSDBeacon>(osdmap->get_epoch(),
+                                    min_last_epoch_clean);
+  return monc->send_message(m);
+}
+
+void OSD::update_heartbeat_peers()
+{
+  if (!state.is_active()) {
+    return;
+  }
+  for (auto& pg : pgs) {
+    vector<int> up, acting;
+    osdmap->pg_to_up_acting_osds(pg.first.pgid,
+                                 &up, nullptr,
+                                 &acting, nullptr);
+    for (auto osd : boost::join(up, acting)) {
+      if (osd != CRUSH_ITEM_NONE) {
+        heartbeat->add_peer(osd, osdmap->get_epoch());
+      }
+    }
+  }
+  heartbeat->update_peers(whoami);
+}
diff --git a/src/crimson/osd/osd.h b/src/crimson/osd/osd.h
new file mode 100644
index 00000000..c5aff5e2
--- /dev/null
+++ b/src/crimson/osd/osd.h
@@ -0,0 +1,125 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <map>
+#include <seastar/core/future.hh>
+#include <seastar/core/gate.hh>
+#include <seastar/core/shared_ptr.hh>
+#include <seastar/core/timer.hh>
+
+#include "crimson/common/simple_lru.h"
+#include "crimson/common/shared_lru.h"
+#include "crimson/mon/MonClient.h"
+#include "crimson/net/Dispatcher.h"
+#include "crimson/osd/chained_dispatchers.h"
+#include "crimson/osd/osdmap_service.h"
+#include "crimson/osd/state.h"
+
+#include "osd/OSDMap.h"
+
+class MOSDMap;
+class OSDMap;
+class OSDMeta;
+class PG;
+class Heartbeat;
+
+namespace ceph::net {
+  class Messenger;
+}
+
+namespace ceph::os {
+  class CyanStore;
+  struct Collection;
+  class Transaction;
+}
+
+template<typename T> using Ref = boost::intrusive_ptr<T>;
+
+class OSD : public ceph::net::Dispatcher,
+	    private OSDMapService {
+  seastar::gate gate;
+  const int whoami;
+  const uint32_t nonce;
+  seastar::timer<seastar::lowres_clock> beacon_timer;
+  // talk with osd
+  ceph::net::Messenger* cluster_msgr = nullptr;
+  // talk with client/mon/mgr
+  ceph::net::Messenger* public_msgr = nullptr;
+  ChainedDispatchers dispatchers;
+  std::unique_ptr<ceph::mon::Client> monc;
+
+  std::unique_ptr<Heartbeat> heartbeat;
+  seastar::timer<seastar::lowres_clock> heartbeat_timer;
+
+  SharedLRU<epoch_t, OSDMap> osdmaps;
+  SimpleLRU<epoch_t, bufferlist, false> map_bl_cache;
+  cached_map_t osdmap;
+  // TODO: use a wrapper for ObjectStore
+  std::unique_ptr<ceph::os::CyanStore> store;
+  std::unique_ptr<OSDMeta> meta_coll;
+
+  std::unordered_map<spg_t, Ref<PG>> pgs;
+  OSDState state;
+
+  /// _first_ epoch we were marked up (after this process started)
+  epoch_t boot_epoch = 0;
+  /// _most_recent_ epoch we were marked up
+  epoch_t up_epoch = 0;
+  //< epoch we last did a bind to new ip:ports
+  epoch_t bind_epoch = 0;
+  //< since when there is no more pending pg creates from mon
+  epoch_t last_pg_create_epoch = 0;
+
+  OSDSuperblock superblock;
+
+  // Dispatcher methods
+  seastar::future<> ms_dispatch(ceph::net::ConnectionRef conn, MessageRef m) override;
+  seastar::future<> ms_handle_connect(ceph::net::ConnectionRef conn) override;
+  seastar::future<> ms_handle_reset(ceph::net::ConnectionRef conn) override;
+  seastar::future<> ms_handle_remote_reset(ceph::net::ConnectionRef conn) override;
+
+public:
+  OSD(int id, uint32_t nonce);
+  ~OSD() override;
+
+  seastar::future<> mkfs(uuid_d fsid);
+
+  seastar::future<> start();
+  seastar::future<> stop();
+
+private:
+  seastar::future<> start_boot();
+  seastar::future<> _preboot(version_t oldest_osdmap, version_t newest_osdmap);
+  seastar::future<> _send_boot();
+
+  seastar::future<Ref<PG>> load_pg(spg_t pgid);
+  seastar::future<> load_pgs();
+
+  // OSDMapService methods
+  seastar::future<cached_map_t> get_map(epoch_t e) override;
+  cached_map_t get_map() const override;
+
+  seastar::future<bufferlist> load_map_bl(epoch_t e);
+  void store_map_bl(ceph::os::Transaction& t,
+                    epoch_t e, bufferlist&& bl);
+  seastar::future<> store_maps(ceph::os::Transaction& t,
+                               epoch_t start, Ref<MOSDMap> m);
+  seastar::future<> osdmap_subscribe(version_t epoch, bool force_request);
+
+  void write_superblock(ceph::os::Transaction& t);
+  seastar::future<> read_superblock();
+
+  seastar::future<> handle_osd_map(ceph::net::ConnectionRef conn,
+                                   Ref<MOSDMap> m);
+  seastar::future<> committed_osd_maps(version_t first,
+                                       version_t last,
+                                       Ref<MOSDMap> m);
+  bool should_restart() const;
+  seastar::future<> restart();
+  seastar::future<> shutdown();
+
+  seastar::future<> send_beacon();
+  void update_heartbeat_peers();
+};
diff --git a/src/crimson/osd/osd_meta.cc b/src/crimson/osd/osd_meta.cc
new file mode 100644
index 00000000..6eb225fe
--- /dev/null
+++ b/src/crimson/osd/osd_meta.cc
@@ -0,0 +1,80 @@
+#include "osd_meta.h"
+
+#include "crimson/os/cyan_collection.h"
+#include "crimson/os/cyan_store.h"
+#include "crimson/os/Transaction.h"
+
+void OSDMeta::create(ceph::os::Transaction& t)
+{
+  t.create_collection(coll->cid, 0);
+}
+
+void OSDMeta::store_map(ceph::os::Transaction& t,
+                        epoch_t e, const bufferlist& m)
+{
+  t.write(coll->cid, osdmap_oid(e), 0, m.length(), m);
+}
+
+seastar::future<bufferlist> OSDMeta::load_map(epoch_t e)
+{
+  return store->read(coll,
+                     osdmap_oid(e), 0, 0,
+                     CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
+}
+
+void OSDMeta::store_superblock(ceph::os::Transaction& t,
+                               const OSDSuperblock& superblock)
+{
+  bufferlist bl;
+  encode(superblock, bl);
+  t.write(coll->cid, superblock_oid(), 0, bl.length(), bl);
+}
+
+seastar::future<OSDSuperblock> OSDMeta::load_superblock()
+{
+  return store->read(coll, superblock_oid(), 0, 0)
+    .then([this] (bufferlist&& bl) {
+      auto p = bl.cbegin();
+      OSDSuperblock superblock;
+      decode(superblock, p);
+      return seastar::make_ready_future<OSDSuperblock>(std::move(superblock));
+  });
+}
+
+seastar::future<pg_pool_t,
+                std::string,
+                OSDMeta::ec_profile_t>
+OSDMeta::load_final_pool_info(int64_t pool) {
+  return store->read(coll, final_pool_info_oid(pool),
+                     0, 0).then([this] (bufferlist&& bl) {
+    auto p = bl.cbegin();
+    pg_pool_t pi;
+    string name;
+    ec_profile_t ec_profile;
+    decode(pi, p);
+    decode(name, p);
+    decode(ec_profile, p);
+    return seastar::make_ready_future<pg_pool_t,
+                                      string,
+                                      ec_profile_t>(std::move(pi),
+                                                    std::move(name),
+                                                    std::move(ec_profile));
+  });
+}
+
+ghobject_t OSDMeta::osdmap_oid(epoch_t epoch)
+{
+  string name = fmt::format("osdmap.{}", epoch);
+  return ghobject_t(hobject_t(sobject_t(object_t(name), 0)));
+}
+
+ghobject_t OSDMeta::final_pool_info_oid(int64_t pool)
+{
+  string name = fmt::format("final_pool_{}", pool);
+  return ghobject_t(hobject_t(sobject_t(object_t(name), CEPH_NOSNAP)));
+}
+
+ghobject_t OSDMeta::superblock_oid()
+{
+  return ghobject_t(hobject_t(sobject_t(object_t("osd_superblock"), 0)));
+}
diff --git a/src/crimson/osd/osd_meta.h b/src/crimson/osd/osd_meta.h
new file mode 100644
index 00000000..936d9548
--- /dev/null
+++ b/src/crimson/osd/osd_meta.h
@@ -0,0 +1,53 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <map>
+#include <string>
+#include <seastar/core/future.hh>
+#include "osd/osd_types.h"
+
+namespace ceph::os {
+  class CyanStore;
+  class Collection;
+  class Transaction;
+}
+
+/// metadata shared across PGs, or put in another way,
+/// metadata not specific to certain PGs.
+class OSDMeta {
+  template<typename T> using Ref = boost::intrusive_ptr<T>;
+
+  ceph::os::CyanStore* store;
+  Ref<ceph::os::Collection> coll;
+
+public:
+  OSDMeta(Ref<ceph::os::Collection> coll,
+          ceph::os::CyanStore* store)
+    : store{store}, coll{coll}
+  {}
+
+
+  auto collection() {
+    return coll;
+  }
+  void create(ceph::os::Transaction& t);
+
+  void store_map(ceph::os::Transaction& t,
+                 epoch_t e, const bufferlist& m);
+  seastar::future<bufferlist> load_map(epoch_t e);
+
+  void store_superblock(ceph::os::Transaction& t,
+                        const OSDSuperblock& sb);
+  seastar::future<OSDSuperblock> load_superblock();
+
+  using ec_profile_t = std::map<std::string, std::string>;
+  seastar::future<pg_pool_t,
+                  std::string,
+                  ec_profile_t> load_final_pool_info(int64_t pool);
+private:
+  static ghobject_t osdmap_oid(epoch_t epoch);
+  static ghobject_t final_pool_info_oid(int64_t pool);
+  static ghobject_t superblock_oid();
+};
diff --git a/src/crimson/osd/osdmap_service.h b/src/crimson/osd/osdmap_service.h
new file mode 100644
index 00000000..0a3aaed3
--- /dev/null
+++ b/src/crimson/osd/osdmap_service.h
@@ -0,0 +1,19 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <boost/smart_ptr/local_shared_ptr.hpp>
+
+#include "include/types.h"
+
+class OSDMap;
+
+class OSDMapService {
+public:
+  using cached_map_t = boost::local_shared_ptr<OSDMap>;
+  virtual ~OSDMapService() = default;
+  virtual seastar::future<cached_map_t> get_map(epoch_t e) = 0;
+  /// get the latest map
+  virtual cached_map_t get_map() const = 0;
+};
diff --git a/src/crimson/osd/pg.cc b/src/crimson/osd/pg.cc
new file mode 100644
index 00000000..bc7b8c2d
--- /dev/null
+++ b/src/crimson/osd/pg.cc
@@ -0,0 +1,6 @@
+#include "pg.h"
+
+PG::PG(pg_pool_t&& pool, std::string&& name, ec_profile_t&& ec_profile)
+{
+  // TODO
+}
diff --git a/src/crimson/osd/pg.h b/src/crimson/osd/pg.h
new file mode 100644
index 00000000..4bb672f4
--- /dev/null
+++ b/src/crimson/osd/pg.h
@@ -0,0 +1,21 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <boost/intrusive_ptr.hpp>
+#include <boost/smart_ptr/intrusive_ref_counter.hpp>
+#include <seastar/core/future.hh>
+
+#include "osd/osd_types.h"
+
+template<typename T> using Ref = boost::intrusive_ptr<T>;
+
+class PG : public boost::intrusive_ref_counter<
+  PG,
+  boost::thread_unsafe_counter>
+{
+  using ec_profile_t = std::map<std::string,std::string>;
+public:
+  PG(pg_pool_t&& pool, std::string&& name, ec_profile_t&& ec_profile);
+};
diff --git a/src/crimson/osd/pg_meta.cc b/src/crimson/osd/pg_meta.cc
new file mode 100644
index 00000000..2098e50a
--- /dev/null
+++ b/src/crimson/osd/pg_meta.cc
@@ -0,0 +1,104 @@
+#include "pg_meta.h"
+
+#include <string_view>
+
+#include "crimson/os/cyan_collection.h"
+#include "crimson/os/cyan_store.h"
+
+// prefix pgmeta_oid keys with _ so that PGLog::read_log_and_missing() can
+// easily skip them
+
+static const string_view infover_key = "_infover"sv;
+static const string_view info_key = "_info"sv;
+static const string_view biginfo_key = "_biginfo"sv;
+static const string_view epoch_key = "_epoch"sv;
+static const string_view fastinfo_key = "_fastinfo"sv;
+
+using ceph::os::CyanStore;
+
+PGMeta::PGMeta(CyanStore* store, spg_t pgid)
+  : store{store},
+    pgid{pgid}
+{}
+
+namespace {
+  template<typename T>
+  std::optional<T> find_value(const CyanStore::omap_values_t& values,
+                              string_view key)
+  {
+    auto found = values.find(key);
+    if (found == values.end()) {
+      return {};
+    }
+    auto p = found->second.cbegin();
+    T value;
+    decode(value, p);
+    return std::make_optional(std::move(value));
+  }
+}
+seastar::future<epoch_t> PGMeta::get_epoch()
+{
+  auto ch = store->open_collection(coll_t{pgid});
+  return store->omap_get_values(ch,
+                                pgid.make_pgmeta_oid(),
+                                {string{infover_key},
+                                 string{epoch_key}}).then(
+    [](auto&& values) {
+      {
+        // sanity check
+        auto infover = find_value<__u8>(values, infover_key);
+        assert(infover);
+        if (*infover < 10) {
+          throw std::runtime_error("incompatible pg meta");
+        }
+      }
+      {
+        auto epoch = find_value<epoch_t>(values, epoch_key);
+        assert(epoch);
+        return seastar::make_ready_future<epoch_t>(*epoch);
+      }
+    });
+}
+
+seastar::future<pg_info_t, PastIntervals> PGMeta::load()
+{
+  auto ch = store->open_collection(coll_t{pgid});
+  return store->omap_get_values(ch,
+                                pgid.make_pgmeta_oid(),
+                                {string{infover_key},
+                                 string{info_key},
+                                 string{biginfo_key},
+                                 string{fastinfo_key}}).then(
+    [this](auto&& values) {
+      {
+        // sanity check
+        auto infover = find_value<__u8>(values, infover_key);
+        assert(infover);
+        if (infover < 10) {
+          throw std::runtime_error("incompatible pg meta");
+        }
+      }
+      pg_info_t info;
+      {
+        auto found = find_value<pg_info_t>(values, info_key);
+        assert(found);
+        info = *std::move(found);
+      }
+      PastIntervals past_intervals;
+      {
+        using biginfo_t = std::pair<PastIntervals, decltype(info.purged_snaps)>;
+        auto big_info = find_value<biginfo_t>(values, biginfo_key);
+        assert(big_info);
+        past_intervals = std::move(big_info->first);
+        info.purged_snaps = std::move(big_info->second);
+      }
+      {
+        auto fast_info = find_value<pg_fast_info_t>(values, fastinfo_key);
+        assert(fast_info);
+        fast_info->try_apply_to(&info);
+      }
+      return seastar::make_ready_future<pg_info_t, PastIntervals>(
+        std::move(info),
+        std::move(past_intervals));
+    });
+}
diff --git a/src/crimson/osd/pg_meta.h b/src/crimson/osd/pg_meta.h
new file mode 100644
index 00000000..10f2234a
--- /dev/null
+++ b/src/crimson/osd/pg_meta.h
@@ -0,0 +1,22 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <seastar/core/future.hh>
+#include "osd/osd_types.h"
+
+namespace ceph::os {
+  class CyanStore;
+}
+
+/// PG related metadata
+class PGMeta
+{
+  ceph::os::CyanStore* store;
+  const spg_t pgid;
+public:
+  PGMeta(ceph::os::CyanStore *store, spg_t pgid);
+  seastar::future<epoch_t> get_epoch();
+  seastar::future<pg_info_t, PastIntervals> load();
+};
diff --git a/src/crimson/osd/state.h b/src/crimson/osd/state.h
new file mode 100644
index 00000000..4c445348
--- /dev/null
+++ b/src/crimson/osd/state.h
@@ -0,0 +1,71 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <string_view>
+#include <ostream>
+
+class OSDMap;
+
+class OSDState {
+
+  enum class State {
+    INITIALIZING,
+    PREBOOT,
+    BOOTING,
+    ACTIVE,
+    STOPPING,
+    WAITING_FOR_HEALTHY,
+  };
+
+  State state = State::INITIALIZING;
+
+public:
+  bool is_initializing() const {
+    return state == State::INITIALIZING;
+  }
+  bool is_preboot() const {
+    return state == State::PREBOOT;
+  }
+  bool is_booting() const {
+    return state == State::BOOTING;
+  }
+  bool is_active() const {
+    return state == State::ACTIVE;
+  }
+  bool is_stopping() const {
+    return state == State::STOPPING;
+  }
+  bool is_waiting_for_healthy() const {
+    return state == State::WAITING_FOR_HEALTHY;
+  }
+  void set_preboot() {
+    state = State::PREBOOT;
+  }
+  void set_booting() {
+    state = State::BOOTING;
+  }
+  void set_active() {
+    state = State::ACTIVE;
+  }
+  void set_stopping() {
+    state = State::STOPPING;
+  }
+  std::string_view to_string() const {
+    switch (state) {
+    case State::INITIALIZING: return "initializing";
+    case State::PREBOOT: return "preboot";
+    case State::BOOTING: return "booting";
+    case State::ACTIVE: return "active";
+    case State::STOPPING: return "stopping";
+    case State::WAITING_FOR_HEALTHY: return "waiting_for_healthy";
+    default: return "???";
+    }
+  }
+};
+
+inline std::ostream&
+operator<<(std::ostream& os, const OSDState& s) {
+  return os << s.to_string();
+}