Feature: scheduler: priority-fencing-delay defaults to 0 meaning disabled

This commit also documents the upcoming new behavior as discussed from:

#2012

`priority-fencing-delay` will combine with any static/random delays that
are introduced by `pcmk_delay_base/max` configured for the corresponding
fencing resources. This delay should be significantly greater than,
safely twice, the maximum `pcmk_delay_base/max`. By default, priority
fencing delay is disabled.

Author: gao-yan

doc/Pacemaker_Explained/en-US/Ch-Options.txt

@@ -292,21 +292,21 @@ are +stop+ to attempt to immediately stop pacemaker and stay stopped, or
 on failure. The default is likely to be changed to +panic+ in a future release.
 '(since 2.0.3)'
 
-| priority-fencing-delay  | |
+| priority-fencing-delay  | 0 |
 indexterm:[priority-fencing-delay,Cluster Option]
 indexterm:[Cluster,Option,priority-fencing-delay]
-Enforce specified delay for the fencings that are targeting the lost
+Apply specified delay for the fencings that are targeting the lost
 nodes with the highest total resource priority in case we don't
 have the majority of the nodes in our cluster partition, so that
 the more significant nodes potentially win any fencing match,
 which is especially meaningful under split-brain of 2-node
 cluster. A promoted resource instance takes the base priority + 1
-on calculation if the base priority is not 0. If all the nodes
-have equal priority, then any pcmk_delay_base/max configured for
-the corresponding fencing resources will be applied. Otherwise as
-long as it's set, even if to 0, it takes precedence over any
-configured pcmk_delay_base/max. By default, priority fencing
-delay is disabled. '(since 2.0.4)'
+on calculation if the base priority is not 0. This delay will
+combine with any static/random delays that are introduced by
+`pcmk_delay_base/max` configured for the corresponding fencing
+resources. This delay should be significantly greater than,
+safely twice, the maximum `pcmk_delay_base/max`. By default,
+priority fencing delay is disabled. '(since 2.0.4)'
 
 | cluster-delay | 60s |
 indexterm:[cluster-delay,Cluster Option]

include/crm/pengine/pe_types.h

@@ -176,7 +176,7 @@ struct pe_working_set_s {
     time_t recheck_by;  // Hint to controller to re-run scheduler by this time
     int ninstances;     // Total number of resource instances
     guint shutdown_lock;// How long (seconds) to lock resources to shutdown node
-    int priority_fencing_delay; // Enforced priority fencing delay
+    int priority_fencing_delay; // Priority fencing delay
 };
 
 enum pe_check_parameters {

lib/pengine/common.c

@@ -160,20 +160,20 @@ static pcmk__cluster_option_t pe_opts[] = {
     },
     {
         XML_CONFIG_ATTR_PRIORITY_FENCING_DELAY, NULL, "time", NULL,
-        NULL, pcmk__valid_interval_spec,
-        "Enforced fencing delay targeting the lost nodes with the highest total resource priority",
-        "Enforce specified delay for the fencings that are targeting the lost "
+        "0", pcmk__valid_interval_spec,
+        "Apply fencing delay targeting the lost nodes with the highest total resource priority",
+        "Apply specified delay for the fencings that are targeting the lost "
             "nodes with the highest total resource priority in case we don't "
             "have the majority of the nodes in our cluster partition, so that "
             "the more significant nodes potentially win any fencing match, "
             "which is especially meaningful under split-brain of 2-node "
             "cluster. A promoted resource instance takes the base priority + 1 "
-            "on calculation if the base priority is not 0. If all the nodes "
-            "have equal priority, then any pcmk_delay_base/max configured for "
-            "the corresponding fencing resources will be applied. Otherwise as "
-            "long as it's set, even if to 0, it takes precedence over any "
-            "configured pcmk_delay_base/max. By default, priority fencing "
-            "delay is disabled."
+            "on calculation if the base priority is not 0. This delay will "
+            "combine with any static/random delays that are introduced by "
+            "`pcmk_delay_base/max` configured for the corresponding fencing "
+            "resources. This delay should be significantly greater than, "
+            "safely twice, the maximum `pcmk_delay_base/max`. By default, "
+            "priority fencing delay is disabled."
     },
 
     {

lib/pengine/unpack.c

@@ -233,8 +233,6 @@ unpack_config(xmlNode * config, pe_working_set_t * data_set)
     crm_debug("Concurrent fencing is %s",
               is_set(data_set->flags, pe_flag_concurrent_fencing) ? "enabled" : "disabled");
 
-    // Default value -1 means `priority-fencing-delay` is disabled
-    data_set->priority_fencing_delay = -1;
     value = pe_pref(data_set->config_hash,
                     XML_CONFIG_ATTR_PRIORITY_FENCING_DELAY);
     if (value) {