exporter: New metric for report ceph daemons health

Ceph exporter provide metrics to report ceph daemons communication health using
 the admin socket

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2146728
       https://tracker.ceph.com/issues/68428

Signed-off-by: Juan Miguel Olmo Martínez <jolmomar@redhat.com>

doc/monitoring/index.rst

@@ -64,6 +64,30 @@ in:
 
 It is good to outline that the main tool allowing users to observe and monitor a Ceph cluster is the **Ceph dashboard**. It provides graphics where the most important cluster and service metrics are represented. Most of the examples in this document are extracted from the dashboard graphics or extrapolated from the metrics exposed by the Ceph dashboard.
 
+Ceph daemon health metrics
+==========================
+
+The Ceph exporter provides a metric called ``ceph_daemon_socket_up`` that reports the liveness status of each Ceph daemon that exposes an admin socket.
+
+The ``ceph_daemon_socket_up`` metric indicates the health status of a Ceph daemon based on its ability to respond via the admin socket, where a value of ``1`` means healthy, and ``0`` means unhealthy. Although a Ceph daemon might still be "alive" when it reports ``ceph_daemon_socket_up=0``, this situation highlights a significant issue in its functionality. As such, this metric serves as an excellent tool for detecting problems in any of the main Ceph daemons.
+
+Labels:
+- **``ceph_daemon``**: Identifier of the Ceph daemon exposing an admin socket on the host.
+- **``hostname``**: Name of the host where the Ceph daemon is running.
+
+Example:
+
+.. code-block:: bash
+
+   ceph_daemon_socket_up{ceph_daemon="mds.a",hostname="testhost"} 1
+   ceph_daemon_socket_up{ceph_daemon="osd.1",hostname="testhost"} 0
+
+To identify any Ceph daemons that were not responsive at any point in the last 12 hours, you can use the following PromQL expression:
+
+.. code-block:: bash
+
+   ceph_daemon_socket_up == 0 or min_over_time(ceph_daemon_socket_up[12h]) == 0
+
 
 Performance metrics
 ===================

src/exporter/DaemonMetricCollector.cc

@@ -168,10 +168,17 @@ void DaemonMetricCollector::dump_asok_metrics(bool sort_metrics, int64_t counter
     if (sockClientsPing) {
       bool ok;
       sock_client.ping(&ok);
+      std::string ceph_daemon_socket_up_desc(
+      "Reports the health status of a Ceph daemon, as determined by whether it is able to respond via its admin socket (1 = healthy, 0 = unhealthy).");
+      labels_t ceph_daemon_socket_up_labels;
+      ceph_daemon_socket_up_labels["hostname"] = quote(ceph_get_hostname());
+      ceph_daemon_socket_up_labels["ceph_daemon"] = quote(daemon_name);
+      add_metric(builder, static_cast<int>(ok), "ceph_daemon_socket_up", ceph_daemon_socket_up_desc,
+             "gauge", ceph_daemon_socket_up_labels);
       if (!ok) {
         failures++;
         continue;
-      } 
+      }
     }
     std::string counter_dump_response = dump_response.size() > 0 ? dump_response :
       asok_request(sock_client, "counter dump", daemon_name);

src/exporter/DaemonMetricCollector.h

@@ -42,11 +42,11 @@ public:
   std::map<std::string, AdminSocketClient> clients;
   std::string metrics;
   std::pair<labels_t, std::string> add_fixed_name_metrics(std::string metric_name);
+  void update_sockets();
 
 private:
   std::mutex metrics_mutex;
   std::unique_ptr<MetricsBuilder> builder;
-  void update_sockets();
   void request_loop(boost::asio::steady_timer &timer);
 
   void dump_asok_metric(boost::json::object perf_info,

src/test/exporter/test_exporter.cc

@@ -1,6 +1,8 @@
 #include "common/ceph_argparse.h"
 #include "common/config.h"
 #include "common/config_proxy.h"
+#include "common/admin_socket.h"
+#include "common/admin_socket_client.h"
 #include <gmock/gmock.h>
 #include "gtest/gtest.h"
 #include "common/ceph_context.h"
@@ -8,6 +10,7 @@
 #include "global/global_init.h"
 #include "exporter/util.h"
 #include "exporter/DaemonMetricCollector.h"
+#include <filesystem>
 
 #include <regex>
 #include <string>
@@ -674,6 +677,27 @@ static std::vector<std::pair<std::string, std::string>> promethize_data = {
   {"rocksdb.submit_sync_latency_sum", "ceph_rocksdb_submit_sync_latency_sum"}
 };
 
+
+class AdminSocketTest
+{
+public:
+  explicit AdminSocketTest(AdminSocket *asokc)
+    : m_asokc(asokc)
+  {
+  }
+  bool init(const std::string &uri) {
+    return m_asokc->init(uri);
+  }
+  std::string bind_and_listen(const std::string &sock_path, int *fd) {
+    return m_asokc->bind_and_listen(sock_path, fd);
+  }
+  bool shutdown() {
+    m_asokc->shutdown();
+    return true;
+  }
+  AdminSocket *m_asokc;
+};
+
 int main(int argc, char **argv)
 {
   ::testing::InitGoogleTest(&argc, argv);
@@ -1289,8 +1313,11 @@ ceph_mon_session_rm{ceph_daemon="mon.a"} 577
 # TYPE ceph_mon_session_trim counter
 ceph_mon_session_trim{ceph_daemon="mon.a"} 9
 )";
-  
-  ASSERT_TRUE(collector.metrics.find(expectedMetrics) != std::string::npos);
+
+  std::string actualMetrics = collector.metrics;
+  std::cout << "Actual MON Metrics: " << actualMetrics << std::endl;
+  ASSERT_TRUE(actualMetrics.find(expectedMetrics) != std::string::npos);
+  //ASSERT_TRUE(collector.metrics.find(expectedMetrics) != std::string::npos);
 
   // Test for labeled metrics - RGW
   daemon = "ceph-client.rgw.foo.ceph-node-00.aayrrj.2.93993527376064";
@@ -1452,3 +1479,82 @@ TEST(Exporter, add_fixed_name_metrics) {
     EXPECT_EQ(new_metric.first, expected_labels);
     ASSERT_TRUE(new_metric.second == expected_metric_name);
 }
+
+TEST(Exporter, UpdateSockets) {
+    const std::string mock_dir = "/tmp/fake_sock_dir";
+
+    // Create the mock directory
+    std::filesystem::create_directories(mock_dir);
+
+    // Create a mix of vstart and real cluster mock .asok files
+    std::ofstream(mock_dir + "/ceph-osd.0.asok").close();
+    std::ofstream(mock_dir + "/ceph-mds.a.asok").close();
+    std::ofstream(mock_dir + "/ceph-mgr.chatest-node-00.ijzynn.asok").close();
+    std::ofstream(mock_dir + "/ceph-client.rgw.rgwfoo.chatest-node-00.yqaoen.2.94354846193952.asok").close();
+    std::ofstream(mock_dir + "/ceph-client.ceph-exporter.chatest-node-00.asok").close();
+    std::ofstream(mock_dir + "/ceph-mon.chatest-node-00.asok").close();
+
+    g_conf().set_val("exporter_sock_dir", mock_dir);
+
+    DaemonMetricCollector collector;
+
+    // Run the function that interacts with the mock directory
+    collector.update_sockets();
+
+    // Verify the expected results
+    ASSERT_EQ(collector.clients.size(), 4);
+    ASSERT_TRUE(collector.clients.find("ceph-osd.0") != collector.clients.end());
+    ASSERT_TRUE(collector.clients.find("ceph-mds.a") != collector.clients.end());
+    ASSERT_TRUE(collector.clients.find("ceph-mon.chatest-node-00") != collector.clients.end());
+    ASSERT_TRUE(collector.clients.find("ceph-client.rgw.rgwfoo.chatest-node-00.yqaoen.2.94354846193952") != collector.clients.end());
+
+
+    // Remove the mock directory and files
+    std::filesystem::remove_all(mock_dir);
+}
+
+
+TEST(Exporter, HealthMetrics) {
+    std::map<std::string, AdminSocketClient> clients;
+    DaemonMetricCollector &collector = collector_instance();
+    std::string daemon = "test_daemon";
+    std::string expectedCounterDump = "";
+    std::string expectedCounterSchema = "";
+    std::string metricName = "ceph_daemon_socket_up";
+
+    // Fake admin socket
+    std::string asok_path = "/tmp/" + daemon + ".asok";
+    std::unique_ptr<AdminSocket> asokc = std::make_unique<AdminSocket>(g_ceph_context);
+    AdminSocketClient client(asok_path);
+
+    // Add the daemon clients to the collector
+    clients.insert({daemon, std::move(client)});
+    collector.clients = clients;
+
+    auto verifyMetricValue = [&](const std::string &metricValue, bool shouldInitializeSocket) {
+        collector.metrics = "";
+
+        if (shouldInitializeSocket) {
+            AdminSocketTest asoct(asokc.get());
+            ASSERT_TRUE(asoct.init(asok_path));
+        }
+
+        collector.dump_asok_metrics(true, 5, true, expectedCounterDump, expectedCounterSchema, false);
+
+        if (shouldInitializeSocket) {
+            AdminSocketTest asoct(asokc.get());
+            ASSERT_TRUE(asoct.shutdown());
+        }
+
+        std::string retrievedMetrics = collector.metrics;
+        std::string pattern = metricName + R"(\{[^}]*ceph_daemon=\")" + daemon + R"(\"[^}]*\}\s+)" + metricValue + R"(\b)";
+        std::regex regexPattern(pattern);
+        ASSERT_TRUE(std::regex_search(retrievedMetrics, regexPattern));
+    };
+
+    // Test an admin socket not answering: metric value should be "0"
+    verifyMetricValue("0", false);
+
+    // Test an admin socket answering: metric value should be "1"
+    verifyMetricValue("1", true);
+}