1 files changed, 509 insertions, 0 deletions

diff --git a/ctdb/server/ctdb_monitor.c b/ctdb/server/ctdb_monitor.c
new file mode 100644
index 0000000..ab58ec4
--- /dev/null
+++ b/ctdb/server/ctdb_monitor.c
@@ -0,0 +1,509 @@
+/* 
+   monitoring links to all other nodes to detect dead nodes
+
+
+   Copyright (C) Ronnie Sahlberg 2007
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "system/filesys.h"
+#include "system/network.h"
+#include "system/wait.h"
+
+#include <talloc.h>
+#include <tevent.h>
+
+#include "lib/util/debug.h"
+#include "lib/util/samba_util.h"
+#include "lib/util/util_process.h"
+
+#include "ctdb_private.h"
+
+#include "common/system.h"
+#include "common/common.h"
+#include "common/logging.h"
+
+struct ctdb_monitor_state {
+	TALLOC_CTX *monitor_context;
+	uint32_t next_interval;
+	uint32_t event_script_timeouts;
+};
+
+static void ctdb_check_health(struct tevent_context *ev,
+			      struct tevent_timer *te,
+			      struct timeval t, void *private_data);
+
+static int ctdb_run_notification_script_child(struct ctdb_context *ctdb, const char *event)
+{
+	struct stat st;
+	int ret;
+	char *cmd;
+
+	if (stat(ctdb->notification_script, &st) != 0) {
+		DEBUG(DEBUG_ERR,("Could not stat notification script %s. Can not send notifications.\n", ctdb->notification_script));
+		return -1;
+	}
+	if (!(st.st_mode & S_IXUSR)) {
+		DEBUG(DEBUG_ERR,("Notification script %s is not executable.\n", ctdb->notification_script));
+		return -1;
+	}
+
+	cmd = talloc_asprintf(ctdb, "%s %s\n", ctdb->notification_script, event);
+	CTDB_NO_MEMORY(ctdb, cmd);
+
+	ret = system(cmd);
+	/* if the system() call was successful, translate ret into the
+	   return code from the command
+	*/
+	if (ret != -1) {
+		ret = WEXITSTATUS(ret);
+	}
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR,("Notification script \"%s\" failed with error %d\n", cmd, ret));
+	}
+
+	return ret;
+}
+
+void ctdb_run_notification_script(struct ctdb_context *ctdb, const char *event)
+{
+	pid_t child;
+
+	if (ctdb->notification_script == NULL) {
+		return;
+	}
+
+	child = ctdb_fork(ctdb);
+	if (child == (pid_t)-1) {
+		DEBUG(DEBUG_ERR,("Failed to fork() a notification child process\n"));
+		return;
+	}
+	if (child == 0) {
+		int ret;
+
+		prctl_set_comment("ctdb_notification");
+		ret = ctdb_run_notification_script_child(ctdb, event);
+		if (ret != 0) {
+			DEBUG(DEBUG_ERR,(__location__ " Notification script failed\n"));
+		}
+		_exit(0);
+	}
+
+	return;
+}
+
+/*
+  called when a health monitoring event script finishes
+ */
+static void ctdb_health_callback(struct ctdb_context *ctdb, int status, void *p)
+{
+	struct ctdb_node *node = ctdb->nodes[ctdb->pnn];
+	TDB_DATA data;
+	struct ctdb_node_flag_change c;
+	uint32_t next_interval;
+	int ret;
+	TDB_DATA rddata;
+	struct ctdb_srvid_message rd;
+	const char *state_str = NULL;
+
+	c.pnn = ctdb->pnn;
+	c.old_flags = node->flags;
+
+	ZERO_STRUCT(rd);
+	rd.pnn   = ctdb->pnn;
+	rd.srvid = 0;
+
+	rddata.dptr = (uint8_t *)&rd;
+	rddata.dsize = sizeof(rd);
+
+	if (status == ECANCELED) {
+		DEBUG(DEBUG_ERR,("Monitoring event was cancelled\n"));
+		goto after_change_status;
+	}
+
+	if (status == ETIMEDOUT) {
+		ctdb->monitor->event_script_timeouts++;
+
+		if (ctdb->monitor->event_script_timeouts >=
+		    ctdb->tunable.monitor_timeout_count) {
+			DEBUG(DEBUG_ERR,
+			      ("Maximum monitor timeout count %u reached."
+			       " Making node unhealthy\n",
+			       ctdb->tunable.monitor_timeout_count));
+		} else {
+			/* We pretend this is OK. */
+			goto after_change_status;
+		}
+	} else {
+		ctdb->monitor->event_script_timeouts = 0;
+	}
+
+	if (status != 0 && !(node->flags & NODE_FLAGS_UNHEALTHY)) {
+		DEBUG(DEBUG_NOTICE,("monitor event failed - disabling node\n"));
+		node->flags |= NODE_FLAGS_UNHEALTHY;
+		ctdb->monitor->next_interval = 5;
+
+		ctdb_run_notification_script(ctdb, "unhealthy");
+	} else if (status == 0 && (node->flags & NODE_FLAGS_UNHEALTHY)) {
+		DEBUG(DEBUG_NOTICE,("monitor event OK - node re-enabled\n"));
+		node->flags &= ~NODE_FLAGS_UNHEALTHY;
+		ctdb->monitor->next_interval = 5;
+
+		ctdb_run_notification_script(ctdb, "healthy");
+	}
+
+after_change_status:
+	next_interval = ctdb->monitor->next_interval;
+
+	ctdb->monitor->next_interval *= 2;
+	if (ctdb->monitor->next_interval > ctdb->tunable.monitor_interval) {
+		ctdb->monitor->next_interval = ctdb->tunable.monitor_interval;
+	}
+
+	tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+			 timeval_current_ofs(next_interval, 0),
+			 ctdb_check_health, ctdb);
+
+	if (c.old_flags == node->flags) {
+		return;
+	}
+
+	c.new_flags = node->flags;
+
+	data.dptr = (uint8_t *)&c;
+	data.dsize = sizeof(c);
+
+	/* ask the recovery daemon to push these changes out to all nodes */
+	ctdb_daemon_send_message(ctdb, ctdb->pnn,
+				 CTDB_SRVID_PUSH_NODE_FLAGS, data);
+
+	if (c.new_flags & NODE_FLAGS_UNHEALTHY) {
+		state_str = "UNHEALTHY";
+	} else {
+		state_str = "HEALTHY";
+	}
+
+	/* ask the recmaster to reallocate all addresses */
+	DEBUG(DEBUG_ERR,
+	      ("Node became %s. Ask recovery master to reallocate IPs\n",
+	       state_str));
+	ret = ctdb_daemon_send_message(ctdb, CTDB_BROADCAST_CONNECTED, CTDB_SRVID_TAKEOVER_RUN, rddata);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR,
+		      (__location__
+		       " Failed to send IP takeover run request\n"));
+	}
+}
+
+
+static void ctdb_run_startup(struct tevent_context *ev,
+			     struct tevent_timer *te,
+			     struct timeval t, void *private_data);
+/*
+  called when the startup event script finishes
+ */
+static void ctdb_startup_callback(struct ctdb_context *ctdb, int status, void *p)
+{
+	if (status != 0) {
+		DEBUG(DEBUG_ERR,("startup event failed\n"));
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(5, 0),
+				 ctdb_run_startup, ctdb);
+		return;
+	}
+
+	DEBUG(DEBUG_NOTICE,("startup event OK - enabling monitoring\n"));
+	ctdb_set_runstate(ctdb, CTDB_RUNSTATE_RUNNING);
+	ctdb->monitor->next_interval = 2;
+	ctdb_run_notification_script(ctdb, "startup");
+
+	/* tell all other nodes we've just started up */
+	ctdb_daemon_send_control(ctdb, CTDB_BROADCAST_CONNECTED,
+				 0, CTDB_CONTROL_STARTUP, 0,
+				 CTDB_CTRL_FLAG_NOREPLY,
+				 tdb_null, NULL, NULL);
+
+	tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+			 timeval_current_ofs(ctdb->monitor->next_interval, 0),
+			 ctdb_check_health, ctdb);
+}
+
+static void ctdb_run_startup(struct tevent_context *ev,
+			     struct tevent_timer *te,
+			     struct timeval t, void *private_data)
+{
+	struct ctdb_context *ctdb = talloc_get_type(private_data,
+						    struct ctdb_context);
+	int ret;
+
+	/* This is necessary to avoid the "startup" event colliding
+	 * with the "ipreallocated" event from the takeover run
+	 * following the first recovery.  We might as well serialise
+	 * these things if we can.
+	 */
+	if (ctdb->runstate < CTDB_RUNSTATE_STARTUP) {
+		DEBUG(DEBUG_NOTICE,
+		      ("Not yet in startup runstate. Wait one more second\n"));
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(1, 0),
+				 ctdb_run_startup, ctdb);
+		return;
+	}
+
+	DEBUG(DEBUG_NOTICE,("Running the \"startup\" event.\n"));
+	ret = ctdb_event_script_callback(ctdb,
+					 ctdb->monitor->monitor_context,
+					 ctdb_startup_callback,
+					 ctdb, CTDB_EVENT_STARTUP, "%s", "");
+
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR,("Unable to launch startup event script\n"));
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(5, 0),
+				 ctdb_run_startup, ctdb);
+	}
+}
+
+/*
+  wait until we have finished initial recoveries before we start the
+  monitoring events
+ */
+static void ctdb_wait_until_recovered(struct tevent_context *ev,
+				      struct tevent_timer *te,
+				      struct timeval t, void *private_data)
+{
+	struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
+	int ret;
+	static int count = 0;
+
+	count++;
+
+	if (count < 60 || count%600 == 0) { 
+		DEBUG(DEBUG_NOTICE,("CTDB_WAIT_UNTIL_RECOVERED\n"));
+		if (ctdb->nodes[ctdb->pnn]->flags & NODE_FLAGS_STOPPED) {
+			DEBUG(DEBUG_NOTICE,("Node is STOPPED. Node will NOT recover.\n"));
+		}
+	}
+
+	if (ctdb->vnn_map->generation == INVALID_GENERATION) {
+		ctdb->db_persistent_startup_generation = INVALID_GENERATION;
+
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(1, 0),
+				 ctdb_wait_until_recovered, ctdb);
+		return;
+	}
+
+	if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
+		ctdb->db_persistent_startup_generation = INVALID_GENERATION;
+
+		DEBUG(DEBUG_NOTICE,(__location__ " in recovery. Wait one more second\n"));
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(1, 0),
+				 ctdb_wait_until_recovered, ctdb);
+		return;
+	}
+
+
+	if (!fast_start && timeval_elapsed(&ctdb->last_recovery_finished) < (ctdb->tunable.rerecovery_timeout + 3)) {
+		ctdb->db_persistent_startup_generation = INVALID_GENERATION;
+
+		DEBUG(DEBUG_NOTICE,(__location__ " wait for pending recoveries to end. Wait one more second.\n"));
+
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(1, 0),
+				 ctdb_wait_until_recovered, ctdb);
+		return;
+	}
+
+	if (ctdb->vnn_map->generation == ctdb->db_persistent_startup_generation) {
+		DEBUG(DEBUG_INFO,(__location__ " skip ctdb_recheck_persistent_health() "
+				  "until the next recovery\n"));
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(1, 0),
+				 ctdb_wait_until_recovered, ctdb);
+		return;
+	}
+
+	ctdb->db_persistent_startup_generation = ctdb->vnn_map->generation;
+	ret = ctdb_recheck_persistent_health(ctdb);
+	if (ret != 0) {
+		ctdb->db_persistent_check_errors++;
+		if (ctdb->db_persistent_check_errors < ctdb->max_persistent_check_errors) {
+			DEBUG(DEBUG_ERR,
+			      (__location__ "ctdb_recheck_persistent_health() "
+			      "failed (%llu of %llu times) - retry later\n",
+			      (unsigned long long)ctdb->db_persistent_check_errors,
+			      (unsigned long long)ctdb->max_persistent_check_errors));
+			tevent_add_timer(ctdb->ev,
+					 ctdb->monitor->monitor_context,
+					 timeval_current_ofs(1, 0),
+					 ctdb_wait_until_recovered, ctdb);
+			return;
+		}
+		DEBUG(DEBUG_ALERT,(__location__
+				  "ctdb_recheck_persistent_health() failed (%llu times) - prepare shutdown\n",
+				  (unsigned long long)ctdb->db_persistent_check_errors));
+		ctdb_shutdown_sequence(ctdb, 11);
+		/* In case above returns due to duplicate shutdown */
+		return;
+	}
+	ctdb->db_persistent_check_errors = 0;
+
+	tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+			 timeval_current(), ctdb_run_startup, ctdb);
+}
+
+
+/*
+  see if the event scripts think we are healthy
+ */
+static void ctdb_check_health(struct tevent_context *ev,
+			      struct tevent_timer *te,
+			      struct timeval t, void *private_data)
+{
+	struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
+	bool skip_monitoring = false;
+	int ret = 0;
+
+	if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL ||
+	    ctdb->nodes[ctdb->pnn]->flags & NODE_FLAGS_INACTIVE ||
+	    ctdb->runstate != CTDB_RUNSTATE_RUNNING) {
+		skip_monitoring = true;
+	} else {
+		if (ctdb_db_all_frozen(ctdb)) {
+			DEBUG(DEBUG_ERR,
+			      ("Skip monitoring since databases are frozen\n"));
+			skip_monitoring = true;
+		}
+	}
+
+	if (skip_monitoring) {
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(ctdb->monitor->next_interval, 0),
+				 ctdb_check_health, ctdb);
+		return;
+	}
+
+	ret = ctdb_event_script_callback(ctdb,
+					 ctdb->monitor->monitor_context,
+					 ctdb_health_callback,
+					 ctdb, CTDB_EVENT_MONITOR, "%s", "");
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR,("Unable to launch monitor event script\n"));
+		ctdb->monitor->next_interval = 5;
+		tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+				 timeval_current_ofs(5, 0),
+				 ctdb_check_health, ctdb);
+	}
+}
+
+/* stop any monitoring 
+   this should only be done when shutting down the daemon
+*/
+void ctdb_stop_monitoring(struct ctdb_context *ctdb)
+{
+	if (ctdb->monitor == NULL) {
+		D_NOTICE("Monitoring not yet initialised\n");
+		return;
+	}
+
+	TALLOC_FREE(ctdb->monitor->monitor_context);
+
+	ctdb->monitor->next_interval = 5;
+	DEBUG(DEBUG_NOTICE,("Monitoring has been stopped\n"));
+}
+
+/*
+  start watching for nodes that might be dead
+ */
+void ctdb_wait_for_first_recovery(struct ctdb_context *ctdb)
+{
+	ctdb_set_runstate(ctdb, CTDB_RUNSTATE_FIRST_RECOVERY);
+
+	ctdb->monitor = talloc(ctdb, struct ctdb_monitor_state);
+	CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor);
+
+	ctdb->monitor->monitor_context = talloc_new(ctdb->monitor);
+	CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor->monitor_context);
+
+	tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
+			 timeval_current_ofs(1, 0),
+			 ctdb_wait_until_recovered, ctdb);
+}
+
+
+/*
+  modify flags on a node
+ */
+int32_t ctdb_control_modflags(struct ctdb_context *ctdb, TDB_DATA indata)
+{
+	struct ctdb_node_flag_change *c = (struct ctdb_node_flag_change *)indata.dptr;
+	struct ctdb_node *node;
+	uint32_t old_flags;
+
+	/*
+	 * Don't let other nodes override the current node's flags.
+	 * The recovery master fetches flags from this node so there's
+	 * no need to push them back.  Doing so is racy.
+	 */
+	if (c->pnn == ctdb->pnn) {
+		DBG_DEBUG("Ignoring flag changes for current node\n");
+		return 0;
+	}
+
+	node = ctdb_find_node(ctdb, c->pnn);
+	if (node == NULL) {
+		DBG_ERR("Node %u is invalid\n", c->pnn);
+		return -1;
+	}
+
+	if (node->flags & NODE_FLAGS_DISCONNECTED) {
+		DBG_DEBUG("Ignoring flag changes for disconnected node\n");
+		return 0;
+	}
+
+	/*
+	 * Remember the old flags.  We don't care what some other node
+	 * thought the old flags were - that's irrelevant.
+	 */
+	old_flags = node->flags;
+
+	/*
+	 * This node tracks nodes it is connected to, so don't let
+	 * another node override this
+	 */
+	node->flags =
+		(old_flags & NODE_FLAGS_DISCONNECTED) |
+		(c->new_flags & ~NODE_FLAGS_DISCONNECTED);
+
+	if (node->flags == old_flags) {
+		return 0;
+	}
+
+	D_NOTICE("Node %u has changed flags - 0x%x -> 0x%x\n",
+		 c->pnn,
+		 old_flags,
+		 node->flags);
+
+	if (node->flags == 0 && ctdb->runstate <= CTDB_RUNSTATE_STARTUP) {
+		DBG_ERR("Node %u became healthy - force recovery for startup\n",
+			c->pnn);
+		ctdb->recovery_mode = CTDB_RECOVERY_ACTIVE;
+	}
+
+	return 0;
+}