osd: Retain overridden mClock recovery settings across osd restarts

Fix an issue where an overridden mClock recovery setting (set prior to
an osd restart) could be lost after an osd restart.

For e.g., consider that prior to an osd restart, the option
'osd_max_backfill' was successfully set to a value different from the
mClock default. If the osd was restarted for some reason, the
boot-up sequence was incorrectly resetting the backfill value to the
mclock default within the async local/remote reservers. This fix
ensures that no change is made if the current overriden value is
different from the mClock default.

Modify an existing standalone test to verify that the local and remote
async reservers are updated to the desired number of backfills under
normal conditions and also across osd restarts.

Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>

diff --git a/qa/standalone/misc/mclock-config.sh b/qa/standalone/misc/mclock-config.sh
index d16cd45f43fa6873a8afc97b8cdba2629d0a5b7d..6ba26af477b12cc5f0fd358a34ec16aea32e12f5 100755 (executable)
--- a/qa/standalone/misc/mclock-config.sh
+++ b/qa/standalone/misc/mclock-config.sh
@@ -247,9 +247,9 @@ function TEST_backfill_limit_adjustment_mclock() {
 
     run_osd $dir 0 --osd_op_queue=mclock_scheduler || return 1
     local backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
-        config get osd_max_backfills)
+        config get osd_max_backfills | jq .osd_max_backfills | bc)
     # Get default value
-    echo "$backfills" | grep --quiet 'osd_max_backfills' || return 1
+    echo "osd_max_backfills: $backfills" || return 1
 
     # Change the backfill limit without setting
     # osd_mclock_override_recovery_settings option. Verify that the backfill
@@ -257,8 +257,16 @@ function TEST_backfill_limit_adjustment_mclock() {
     ceph config set osd.0 osd_max_backfills 20 || return 1
     sleep 2 # Allow time for change to take effect
     local max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
-        config get osd_max_backfills)
-    test "$max_backfills" = "$backfills" || return 1
+        config get osd_max_backfills | jq .osd_max_backfills | bc)
+    test $max_backfills = $backfills || return 1
+
+    # Verify local and async reserver settings are not changed
+    max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
+        dump_recovery_reservations | jq .local_reservations.max_allowed | bc)
+    test $max_backfills = $backfills || return 1
+    max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
+        dump_recovery_reservations | jq .remote_reservations.max_allowed | bc)
+    test $max_backfills = $backfills || return 1
 
     # Change backfills limit after setting osd_mclock_override_recovery_settings.
     # Verify that the backfills limit is modified.
@@ -266,8 +274,35 @@ function TEST_backfill_limit_adjustment_mclock() {
     ceph config set osd.0 osd_max_backfills 20 || return 1
     sleep 2 # Allow time for change to take effect
     max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
-        config get osd_max_backfills)
-    test "$max_backfills" =  '{"osd_max_backfills":"20"}' || return 1
+        config get osd_max_backfills | jq .osd_max_backfills | bc)
+    test $max_backfills = 20 || return 1
+
+    # Verify local and async reserver settings are changed
+    max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
+        dump_recovery_reservations | jq .local_reservations.max_allowed | bc)
+    test $max_backfills = 20 || return 1
+    max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
+        dump_recovery_reservations | jq .remote_reservations.max_allowed | bc)
+    test $max_backfills = 20 || return 1
+
+    # Kill osd and bring it back up.
+    # Confirm that the backfill settings are retained.
+    kill_daemons $dir TERM osd || return 1
+    ceph osd down 0 || return 1
+    wait_for_osd down 0 || return 1
+    activate_osd $dir 0 --osd-op-queue=mclock_scheduler || return 1
+
+    max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
+        config get osd_max_backfills | jq .osd_max_backfills | bc)
+    test $max_backfills = 20 || return 1
+
+    # Verify local and async reserver settings are changed
+    max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
+        dump_recovery_reservations | jq .local_reservations.max_allowed | bc)
+    test $max_backfills = 20 || return 1
+    max_backfills=$(CEPH_ARGS='' ceph --format=json daemon $(get_asok_path osd.0) \
+        dump_recovery_reservations | jq .remote_reservations.max_allowed | bc)
+    test $max_backfills = 20 || return 1
 
     teardown $dir || return 1
 }

diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index 8fd0d1cb114d9a0a2555ac0fe235588ab3bb0f94..2775e8c0b42f78f0cebed4318b8c642c25505b37 100644 (file)
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -10320,17 +10320,28 @@ bool OSD::maybe_override_options_for_qos(const std::set<std::string> *changed)
         }
       }
     } else { // if (changed != nullptr) (osd boot-up)
-      // Override the default recovery max active and max backfills to
-      // higher values based on the type of backing device (hdd/ssd).
-      // This section is executed only during osd boot-up.
+      /**
+       * This section is executed only during osd boot-up.
+       * Override the default recovery max active (hdd & ssd) and max backfills
+       * config options to either the mClock defaults or retain their respective
+       * overridden values before the osd was restarted.
+       */
       for (auto opt : recovery_qos_defaults) {
+        /**
+         * Note: set_val_default doesn't overwrite an option if it was earlier
+         * set at a config level greater than CONF_DEFAULT. It doesn't return
+         * a status. With get_val(), the config subsystem is guaranteed to
+         * either return the overridden value (if any) or the default value.
+         */
         cct->_conf.set_val_default(opt.first, std::to_string(opt.second));
+        auto opt_val = cct->_conf.get_val<uint64_t>(opt.first);
+        dout(1) << __func__ << " "
+                << opt.first << " set to " << opt_val
+                << dendl;
         if (opt.first == "osd_max_backfills") {
-          service.local_reserver.set_max(opt.second);
-          service.remote_reserver.set_max(opt.second);
+          service.local_reserver.set_max(opt_val);
+          service.remote_reserver.set_max(opt_val);
         }
-        dout(1) << __func__ << " Set default value for " << opt.first
-                << " to " << opt.second << dendl;
       }
     }
     return true;