diff --git a/doc/sphinx/Pacemaker_Explained/options.rst b/doc/sphinx/Pacemaker_Explained/options.rst
index b3f052722d..d38a2ab892 100644
--- a/doc/sphinx/Pacemaker_Explained/options.rst
+++ b/doc/sphinx/Pacemaker_Explained/options.rst
@@ -1,801 +1,921 @@
Cluster-Wide Configuration
--------------------------
.. index::
pair: XML element; cib
pair: XML element; configuration
Configuration Layout
####################
The cluster is defined by the Cluster Information Base (CIB), which uses XML
notation. The simplest CIB, an empty one, looks like this:
.. topic:: An empty configuration
.. code-block:: xml
The empty configuration above contains the major sections that make up a CIB:
* ``cib``: The entire CIB is enclosed with a ``cib`` element. Certain
fundamental settings are defined as attributes of this element.
* ``configuration``: This section -- the primary focus of this document --
contains traditional configuration information such as what resources the
cluster serves and the relationships among them.
* ``crm_config``: cluster-wide configuration options
* ``nodes``: the machines that host the cluster
* ``resources``: the services run by the cluster
* ``constraints``: indications of how resources should be placed
* ``status``: This section contains the history of each resource on each
node. Based on this data, the cluster can construct the complete current
state of the cluster. The authoritative source for this section is the
local executor (pacemaker-execd process) on each cluster node, and the
cluster will occasionally repopulate the entire section. For this reason,
it is never written to disk, and administrators are advised against
modifying it in any way.
In this document, configuration settings will be described as properties or
options based on how they are defined in the CIB:
* Properties are XML attributes of an XML element.
* Options are name-value pairs expressed as ``nvpair`` child elements of an XML
element.
Normally, you will use command-line tools that abstract the XML, so the
distinction will be unimportant; both properties and options are cluster
settings you can tweak.
Configuration Value Types
#########################
Throughout this document, configuration values will be designated as having one
of the following types:
.. list-table:: **Configuration Value Types**
:class: longtable
:widths: 1 3
:header-rows: 1
* - Type
- Description
* - .. _boolean:
.. index::
pair: type; boolean
boolean
- Case-insensitive text value where ``1``, ``yes``, ``y``, ``on``,
and ``true`` evaluate as true and ``0``, ``no``, ``n``, ``off``,
``false``, and unset evaluate as false
* - .. _date_time:
.. index::
pair: type; date/time
date/time
- Textual timestamp like ``Sat Dec 21 11:47:45 2013``
+ * - .. _duration:
+
+ .. index::
+ pair: type; duration
+
+ duration
+ - A time duration, specified either like a :ref:`timeout ` or an
+ `ISO 8601 duration `_.
+ A duration may be up to approximately 49 days but is intended for much
+ smaller time periods.
* - .. _enumeration:
.. index::
pair: type; enumeration
enumeration
- Text that must be one of a set of defined values (which will be listed
in the description)
* - .. _integer:
.. index::
pair: type; integer
integer
- 32-bit signed integer value (-2,147,483,648 to 2,147,483,647)
* - .. _nonnegative_integer:
.. index::
pair: type; nonnegative integer
nonnegative integer
- 32-bit nonnegative integer value (0 to 2,147,483,647)
* - .. _port:
.. index::
pair: type; port
port
- Integer TCP port number (0 to 65535)
* - .. _score:
.. index::
pair: type; score
score
- A Pacemaker score can be an integer between -1,000,000 and 1,000,000, or
a string alias: ``INFINITY`` or ``+INFINITY`` is equivalent to
1,000,000, ``-INFINITY`` is equivalent to -1,000,000, and ``red``,
``yellow``, and ``green`` are equivalent to integers as described in
:ref:`node-health`.
* - .. _text:
.. index::
pair: type; text
text
- A text string
+ * - .. _timeout:
+
+ .. index::
+ pair: type; timeout
+
+ timeout
+ - A time duration, specified as a bare number (in which case it is
+ considered to be in seconds) or a number with a unit (``ms`` or ``msec``
+ for milliseconds, ``us`` or ``usec`` for microseconds, ``s`` or ``sec``
+ for seconds, ``m`` or ``min`` for minutes, ``h`` or ``hr`` for hours)
+ optionally with whitespace before and/or after the number.
* - .. _version:
.. index::
pair: type; version
version
- - Version number (three integers separated by dots)
+ - Version number (any combination of alphanumeric characters, dots, and
+ dashes, starting with a number).
Scores
______
Scores are integral to how Pacemaker works. Practically everything from moving
a resource to deciding which resource to stop in a degraded cluster is achieved
by manipulating scores in some way.
Scores are calculated per resource and node. Any node with a negative score for
a resource can't run that resource. The cluster places a resource on the node
with the highest score for it.
Score addition and subtraction follow these rules:
* Any value (including ``INFINITY``) - ``INFINITY`` = ``-INFINITY``
* ``INFINITY`` + any value other than ``-INFINITY`` = ``INFINITY``
.. note::
What if you want to use a score higher than 1,000,000? Typically this possibility
arises when someone wants to base the score on some external metric that might
go above 1,000,000.
The short answer is you can't.
The long answer is it is sometimes possible work around this limitation
creatively. You may be able to set the score to some computed value based on
the external metric rather than use the metric directly. For nodes, you can
store the metric as a node attribute, and query the attribute when computing
the score (possibly as part of a custom resource agent).
CIB Properties
##############
Certain settings are defined by CIB properties (that is, attributes of the
``cib`` tag) rather than with the rest of the cluster configuration in the
``configuration`` section.
The reason is simply a matter of parsing. These options are used by the
configuration database which is, by design, mostly ignorant of the content it
holds. So the decision was made to place them in an easy-to-find location.
.. list-table:: **CIB Properties**
:class: longtable
:widths: 2 2 2 5
:header-rows: 1
- * - Attribute
+ * - Name
- Type
- Default
- Description
* - .. _admin_epoch:
.. index::
pair: admin_epoch; cib
admin_epoch
- :ref:`nonnegative integer `
- 0
- When a node joins the cluster, the cluster asks the node with the
highest (``admin_epoch``, ``epoch``, ``num_updates``) tuple to replace
the configuration on all the nodes -- which makes setting them correctly
very important. ``admin_epoch`` is never modified by the cluster; you
can use this to make the configurations on any inactive nodes obsolete.
* - .. _epoch:
.. index::
pair: epoch; cib
epoch
- :ref:`nonnegative integer `
- 0
- The cluster increments this every time the CIB's configuration section
is updated.
* - .. _num_updates:
.. index::
pair: num_updates; cib
num_updates
- :ref:`nonnegative integer `
- 0
- The cluster increments this every time the CIB's configuration or status
sections are updated, and resets it to 0 when epoch changes.
* - .. _validate_with:
.. index::
pair: validate-with; cib
validate-with
- :ref:`enumeration `
-
- Determines the type of XML validation that will be done on the
configuration. Allowed values are ``none`` (in which case the cluster
will not require that updates conform to expected syntax) and the base
names of schema files installed on the local machine (for example,
"pacemaker-3.9")
* - .. _remote_tls_port:
.. index::
pair: remote-tls-port; cib
remote-tls-port
- :ref:`port `
-
- If set, the CIB manager will listen for anonymously encrypted remote
connections on this port, to allow CIB administration from hosts not in
the cluster. No key is used, so this should be used only on a protected
network where man-in-the-middle attacks can be avoided.
* - .. _remote_clear_port:
.. index::
pair: remote-clear-port; cib
remote-clear-port
- :ref:`port `
-
- If set to a TCP port number, the CIB manager will listen for remote
connections on this port, to allow for CIB administration from hosts not
in the cluster. No encryption is used, so this should be used only on a
protected network.
* - .. _cib_last_written:
.. index::
pair: cib-last-written; cib
cib-last-written
- :ref:`date/time `
-
- Indicates when the configuration was last written to disk. Maintained by
the cluster; for informational purposes only.
* - .. _have_quorum:
.. index::
pair: have-quorum; cib
have-quorum
- :ref:`boolean `
-
- Indicates whether the cluster has quorum. If false, the cluster's
response is determined by ``no-quorum-policy`` (see below). Maintained
by the cluster.
* - .. _dc_uuid:
.. index::
pair: dc-uuid; cib
dc-uuid
- :ref:`text `
-
- Node ID of the cluster's current designated controller (DC). Used and
maintained by the cluster.
.. _cluster_options:
Cluster Options
###############
Cluster options, as you might expect, control how the cluster behaves when
confronted with various situations.
They are grouped into sets within the ``crm_config`` section. In advanced
configurations, there may be more than one set. (This will be described later
in the chapter on :ref:`rules` where we will show how to have the cluster use
different sets of options during working hours than during weekends.) For now,
we will describe the simple case where each option is present at most once.
You can obtain an up-to-date list of cluster options, including their default
values, by running the ``man pacemaker-schedulerd`` and
``man pacemaker-controld`` commands.
-.. table:: **Cluster Options**
+.. list-table:: **Cluster Options**
:class: longtable
- :widths: 2 1 4
-
- +---------------------------+---------+----------------------------------------------------+
- | Option | Default | Description |
- +===========================+=========+====================================================+
- | cluster-name | | .. index:: |
- | | | pair: cluster option; cluster-name |
- | | | |
- | | | An (optional) name for the cluster as a whole. |
- | | | This is mostly for users' convenience for use |
- | | | as desired in administration, but this can be |
- | | | used in the Pacemaker configuration in |
- | | | :ref:`rules` (as the ``#cluster-name`` |
- | | | :ref:`node attribute |
- | | | `. It may |
- | | | also be used by higher-level tools when |
- | | | displaying cluster information, and by |
- | | | certain resource agents (for example, the |
- | | | ``ocf:heartbeat:GFS2`` agent stores the |
- | | | cluster name in filesystem meta-data). |
- +---------------------------+---------+----------------------------------------------------+
- | dc-version | | .. index:: |
- | | | pair: cluster option; dc-version |
- | | | |
- | | | Version of Pacemaker on the cluster's DC. |
- | | | Determined automatically by the cluster. Often |
- | | | includes the hash which identifies the exact |
- | | | Git changeset it was built from. Used for |
- | | | diagnostic purposes. |
- +---------------------------+---------+----------------------------------------------------+
- | cluster-infrastructure | | .. index:: |
- | | | pair: cluster option; cluster-infrastructure |
- | | | |
- | | | The messaging stack on which Pacemaker is |
- | | | currently running. Determined automatically by |
- | | | the cluster. Used for informational and |
- | | | diagnostic purposes. |
- +---------------------------+---------+----------------------------------------------------+
- | no-quorum-policy | stop | .. index:: |
- | | | pair: cluster option; no-quorum-policy |
- | | | |
- | | | What to do when the cluster does not have |
- | | | quorum. Allowed values: |
- | | | |
- | | | * ``ignore:`` continue all resource management |
- | | | * ``freeze:`` continue resource management, but |
- | | | don't recover resources from nodes not in the |
- | | | affected partition |
- | | | * ``stop:`` stop all resources in the affected |
- | | | cluster partition |
- | | | * ``demote:`` demote promotable resources and |
- | | | stop all other resources in the affected |
- | | | cluster partition *(since 2.0.5)* |
- | | | * ``suicide:`` fence all nodes in the affected |
- | | | cluster partition |
- +---------------------------+---------+----------------------------------------------------+
- | batch-limit | 0 | .. index:: |
- | | | pair: cluster option; batch-limit |
- | | | |
- | | | The maximum number of actions that the cluster |
- | | | may execute in parallel across all nodes. The |
- | | | "correct" value will depend on the speed and |
- | | | load of your network and cluster nodes. If zero, |
- | | | the cluster will impose a dynamically calculated |
- | | | limit only when any node has high load. If -1, the |
- | | | cluster will not impose any limit. |
- +---------------------------+---------+----------------------------------------------------+
- | migration-limit | -1 | .. index:: |
- | | | pair: cluster option; migration-limit |
- | | | |
- | | | The number of |
- | | | :ref:`live migration ` actions |
- | | | that the cluster is allowed to execute in |
- | | | parallel on a node. A value of -1 means |
- | | | unlimited. |
- +---------------------------+---------+----------------------------------------------------+
- | symmetric-cluster | true | .. index:: |
- | | | pair: cluster option; symmetric-cluster |
- | | | |
- | | | Whether resources can run on any node by default |
- | | | (if false, a resource is allowed to run on a |
- | | | node only if a |
- | | | :ref:`location constraint ` |
- | | | enables it) |
- +---------------------------+---------+----------------------------------------------------+
- | stop-all-resources | false | .. index:: |
- | | | pair: cluster option; stop-all-resources |
- | | | |
- | | | Whether all resources should be disallowed from |
- | | | running (can be useful during maintenance) |
- +---------------------------+---------+----------------------------------------------------+
- | stop-orphan-resources | true | .. index:: |
- | | | pair: cluster option; stop-orphan-resources |
- | | | |
- | | | Whether resources that have been deleted from |
- | | | the configuration should be stopped. This value |
- | | | takes precedence over |
- | | | :ref:`is-managed ` (that is, even |
- | | | unmanaged resources will be stopped when orphaned |
- | | | if this value is ``true``). |
- +---------------------------+---------+----------------------------------------------------+
- | stop-orphan-actions | true | .. index:: |
- | | | pair: cluster option; stop-orphan-actions |
- | | | |
- | | | Whether recurring :ref:`operations ` |
- | | | that have been deleted from the configuration |
- | | | should be cancelled |
- +---------------------------+---------+----------------------------------------------------+
- | start-failure-is-fatal | true | .. index:: |
- | | | pair: cluster option; start-failure-is-fatal |
- | | | |
- | | | Whether a failure to start a resource on a |
- | | | particular node prevents further start attempts |
- | | | on that node? If ``false``, the cluster will |
- | | | decide whether the node is still eligible based |
- | | | on the resource's current failure count and |
- | | | :ref:`migration-threshold `. |
- +---------------------------+---------+----------------------------------------------------+
- | enable-startup-probes | true | .. index:: |
- | | | pair: cluster option; enable-startup-probes |
- | | | |
- | | | Whether the cluster should check the |
- | | | pre-existing state of resources when the cluster |
- | | | starts |
- +---------------------------+---------+----------------------------------------------------+
- | maintenance-mode | false | .. _maintenance_mode: |
- | | | |
- | | | .. index:: |
- | | | pair: cluster option; maintenance-mode |
- | | | |
- | | | If true, the cluster will not start or stop any |
- | | | resource in the cluster, and any recurring |
- | | | operations (expect those specifying ``role`` as |
- | | | ``Stopped``) will be paused. If true, this |
- | | | overrides the |
- | | | :ref:`maintenance ` node |
- | | | attribute, :ref:`is-managed ` and |
- | | | :ref:`maintenance ` resource |
- | | | meta-attributes, and :ref:`enabled ` |
- | | | operation meta-attribute. |
- +---------------------------+---------+----------------------------------------------------+
- | stonith-enabled | true | .. index:: |
- | | | pair: cluster option; stonith-enabled |
- | | | |
- | | | Whether the cluster is allowed to fence nodes |
- | | | (for example, failed nodes and nodes with |
- | | | resources that can't be stopped). |
- | | | |
- | | | If true, at least one fence device must be |
- | | | configured before resources are allowed to run. |
- | | | |
- | | | If false, unresponsive nodes are immediately |
- | | | assumed to be running no resources, and resource |
- | | | recovery on online nodes starts without any |
- | | | further protection (which can mean *data loss* |
- | | | if the unresponsive node still accesses shared |
- | | | storage, for example). See also the |
- | | | :ref:`requires ` resource |
- | | | meta-attribute. |
- +---------------------------+---------+----------------------------------------------------+
- | stonith-action | reboot | .. index:: |
- | | | pair: cluster option; stonith-action |
- | | | |
- | | | Action the cluster should send to the fence agent |
- | | | when a node must be fenced. Allowed values are |
- | | | ``reboot``, ``off``, and (for legacy agents only) |
- | | | ``poweroff``. |
- +---------------------------+---------+----------------------------------------------------+
- | stonith-timeout | 60s | .. index:: |
- | | | pair: cluster option; stonith-timeout |
- | | | |
- | | | How long to wait for ``on``, ``off``, and |
- | | | ``reboot`` fence actions to complete by default. |
- +---------------------------+---------+----------------------------------------------------+
- | stonith-max-attempts | 10 | .. index:: |
- | | | pair: cluster option; stonith-max-attempts |
- | | | |
- | | | How many times fencing can fail for a target |
- | | | before the cluster will no longer immediately |
- | | | re-attempt it. |
- +---------------------------+---------+----------------------------------------------------+
- | stonith-watchdog-timeout | 0 | .. index:: |
- | | | pair: cluster option; stonith-watchdog-timeout |
- | | | |
- | | | If nonzero, and the cluster detects |
- | | | ``have-watchdog`` as ``true``, then watchdog-based |
- | | | self-fencing will be performed via SBD when |
- | | | fencing is required, without requiring a fencing |
- | | | resource explicitly configured. |
- | | | |
- | | | If this is set to a positive value, unseen nodes |
- | | | are assumed to self-fence within this much time. |
- | | | |
- | | | **Warning:** It must be ensured that this value is |
- | | | larger than the ``SBD_WATCHDOG_TIMEOUT`` |
- | | | environment variable on all nodes. Pacemaker |
- | | | verifies the settings individually on all nodes |
- | | | and prevents startup or shuts down if configured |
- | | | wrongly on the fly. It is strongly recommended |
- | | | that ``SBD_WATCHDOG_TIMEOUT`` be set to the same |
- | | | value on all nodes. |
- | | | |
- | | | If this is set to a negative value, and |
- | | | ``SBD_WATCHDOG_TIMEOUT`` is set, twice that value |
- | | | will be used. |
- | | | |
- | | | **Warning:** In this case, it is essential (and |
- | | | currently not verified by pacemaker) that |
- | | | ``SBD_WATCHDOG_TIMEOUT`` is set to the same |
- | | | value on all nodes. |
- +---------------------------+---------+----------------------------------------------------+
- | concurrent-fencing | false | .. index:: |
- | | | pair: cluster option; concurrent-fencing |
- | | | |
- | | | Whether the cluster is allowed to initiate |
- | | | multiple fence actions concurrently. Fence actions |
- | | | initiated externally, such as via the |
- | | | ``stonith_admin`` tool or an application such as |
- | | | DLM, or by the fencer itself such as recurring |
- | | | device monitors and ``status`` and ``list`` |
- | | | commands, are not limited by this option. |
- +---------------------------+---------+----------------------------------------------------+
- | fence-reaction | stop | .. index:: |
- | | | pair: cluster option; fence-reaction |
- | | | |
- | | | How should a cluster node react if notified of its |
- | | | own fencing? A cluster node may receive |
- | | | notification of its own fencing if fencing is |
- | | | misconfigured, or if fabric fencing is in use that |
- | | | doesn't cut cluster communication. Allowed values |
- | | | are ``stop`` to attempt to immediately stop |
- | | | pacemaker and stay stopped, or ``panic`` to |
- | | | attempt to immediately reboot the local node, |
- | | | falling back to stop on failure. The default is |
- | | | likely to be changed to ``panic`` in a future |
- | | | release. *(since 2.0.3)* |
- +---------------------------+---------+----------------------------------------------------+
- | priority-fencing-delay | 0 | .. index:: |
- | | | pair: cluster option; priority-fencing-delay |
- | | | |
- | | | Apply this delay to any fencing 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 (especially meaningful in a split-brain of a |
- | | | 2-node cluster). A promoted resource instance |
- | | | takes the resource's priority plus 1 if the |
- | | | resource's priority is not 0. Any static or random |
- | | | delays introduced by ``pcmk_delay_base`` and |
- | | | ``pcmk_delay_max`` configured for the |
- | | | corresponding fencing resources will be added to |
- | | | this delay. This delay should be significantly |
- | | | greater than (safely twice) the maximum delay from |
- | | | those parameters. *(since 2.0.4)* |
- +---------------------------+---------+----------------------------------------------------+
- | node-pending-timeout | 2h | .. index:: |
- | | | pair: cluster option; node-pending-timeout |
- | | | |
- | | | Fence nodes that do not join the controller |
- | | | process group within this much time after joining |
- | | | the cluster, to allow the cluster to continue |
- | | | managing resources. A value of 0 means never fence |
- | | | pending nodes. *(since 2.1.7)* |
- +---------------------------+---------+----------------------------------------------------+
- | cluster-delay | 60s | .. index:: |
- | | | pair: cluster option; cluster-delay |
- | | | |
- | | | Estimated maximum round-trip delay over the |
- | | | network (excluding action execution). If the DC |
- | | | requires an action to be executed on another node, |
- | | | it will consider the action failed if it does not |
- | | | get a response from the other node in this time |
- | | | (after considering the action's own timeout). The |
- | | | "correct" value will depend on the speed and load |
- | | | of your network and cluster nodes. |
- +---------------------------+---------+----------------------------------------------------+
- | dc-deadtime | 20s | .. index:: |
- | | | pair: cluster option; dc-deadtime |
- | | | |
- | | | How long to wait for a response from other nodes |
- | | | during startup. The "correct" value will depend on |
- | | | the speed/load of your network and the type of |
- | | | switches used. |
- +---------------------------+---------+----------------------------------------------------+
- | cluster-ipc-limit | 500 | .. index:: |
- | | | pair: cluster option; cluster-ipc-limit |
- | | | |
- | | | The maximum IPC message backlog before one cluster |
- | | | daemon will disconnect another. This is of use in |
- | | | large clusters, for which a good value is the |
- | | | number of resources in the cluster multiplied by |
- | | | the number of nodes. The default of 500 is also |
- | | | the minimum. Raise this if you see |
- | | | "Evicting client" messages for cluster daemon PIDs |
- | | | in the logs. |
- +---------------------------+---------+----------------------------------------------------+
- | pe-error-series-max | -1 | .. index:: |
- | | | pair: cluster option; pe-error-series-max |
- | | | |
- | | | The number of scheduler inputs resulting in errors |
- | | | to save. Used when reporting problems. A value of |
- | | | -1 means unlimited (report all), and 0 means none. |
- +---------------------------+---------+----------------------------------------------------+
- | pe-warn-series-max | 5000 | .. index:: |
- | | | pair: cluster option; pe-warn-series-max |
- | | | |
- | | | The number of scheduler inputs resulting in |
- | | | warnings to save. Used when reporting problems. A |
- | | | value of -1 means unlimited (report all), and 0 |
- | | | means none. |
- +---------------------------+---------+----------------------------------------------------+
- | pe-input-series-max | 4000 | .. index:: |
- | | | pair: cluster option; pe-input-series-max |
- | | | |
- | | | The number of "normal" scheduler inputs to save. |
- | | | Used when reporting problems. A value of -1 means |
- | | | unlimited (report all), and 0 means none. |
- +---------------------------+---------+----------------------------------------------------+
- | enable-acl | false | .. index:: |
- | | | pair: cluster option; enable-acl |
- | | | |
- | | | Whether :ref:`acl` should be used to authorize |
- | | | modifications to the CIB |
- +---------------------------+---------+----------------------------------------------------+
- | placement-strategy | default | .. index:: |
- | | | pair: cluster option; placement-strategy |
- | | | |
- | | | How the cluster should assign resources to nodes |
- | | | (see :ref:`utilization`). Allowed values are |
- | | | ``default``, ``utilization``, ``balanced``, and |
- | | | ``minimal``. |
- +---------------------------+---------+----------------------------------------------------+
- | node-health-strategy | none | .. index:: |
- | | | pair: cluster option; node-health-strategy |
- | | | |
- | | | How the cluster should react to node health |
- | | | attributes (see :ref:`node-health`). Allowed values|
- | | | are ``none``, ``migrate-on-red``, ``only-green``, |
- | | | ``progressive``, and ``custom``. |
- +---------------------------+---------+----------------------------------------------------+
- | node-health-base | 0 | .. index:: |
- | | | pair: cluster option; node-health-base |
- | | | |
- | | | The base health score assigned to a node. Only |
- | | | used when ``node-health-strategy`` is |
- | | | ``progressive``. |
- +---------------------------+---------+----------------------------------------------------+
- | node-health-green | 0 | .. index:: |
- | | | pair: cluster option; node-health-green |
- | | | |
- | | | The score to use for a node health attribute whose |
- | | | value is ``green``. Only used when |
- | | | ``node-health-strategy`` is ``progressive`` or |
- | | | ``custom``. |
- +---------------------------+---------+----------------------------------------------------+
- | node-health-yellow | 0 | .. index:: |
- | | | pair: cluster option; node-health-yellow |
- | | | |
- | | | The score to use for a node health attribute whose |
- | | | value is ``yellow``. Only used when |
- | | | ``node-health-strategy`` is ``progressive`` or |
- | | | ``custom``. |
- +---------------------------+---------+----------------------------------------------------+
- | node-health-red | 0 | .. index:: |
- | | | pair: cluster option; node-health-red |
- | | | |
- | | | The score to use for a node health attribute whose |
- | | | value is ``red``. Only used when |
- | | | ``node-health-strategy`` is ``progressive`` or |
- | | | ``custom``. |
- +---------------------------+---------+----------------------------------------------------+
- | cluster-recheck-interval | 15min | .. index:: |
- | | | pair: cluster option; cluster-recheck-interval |
- | | | |
- | | | Pacemaker is primarily event-driven, and looks |
- | | | ahead to know when to recheck the cluster for |
- | | | failure timeouts and most time-based rules |
- | | | *(since 2.0.3)*. However, it will also recheck the |
- | | | cluster after this amount of inactivity. This has |
- | | | two goals: rules with ``date_spec`` are only |
- | | | guaranteed to be checked this often, and it also |
- | | | serves as a fail-safe for some kinds of scheduler |
- | | | bugs. A value of 0 disables this polling; positive |
- | | | values are a time interval. |
- +---------------------------+---------+----------------------------------------------------+
- | shutdown-lock | false | .. index:: |
- | | | pair: cluster option; shutdown-lock |
- | | | |
- | | | The default of false allows active resources to be |
- | | | recovered elsewhere when their node is cleanly |
- | | | shut down, which is what the vast majority of |
- | | | users will want. However, some users prefer to |
- | | | make resources highly available only for failures, |
- | | | with no recovery for clean shutdowns. If this |
- | | | option is true, resources active on a node when it |
- | | | is cleanly shut down are kept "locked" to that |
- | | | node (not allowed to run elsewhere) until they |
- | | | start again on that node after it rejoins (or for |
- | | | at most ``shutdown-lock-limit``, if set). Stonith |
- | | | resources and Pacemaker Remote connections are |
- | | | never locked. Clone and bundle instances and the |
- | | | promoted role of promotable clones are currently |
- | | | never locked, though support could be added in a |
- | | | future release. Locks may be manually cleared |
- | | | using the ``--refresh`` option of ``crm_resource`` |
- | | | (both the resource and node must be specified; |
- | | | this works with remote nodes if their connection |
- | | | resource's ``target-role`` is set to ``Stopped``, |
- | | | but not if Pacemaker Remote is stopped on the |
- | | | remote node without disabling the connection |
- | | | resource). *(since 2.0.4)* |
- +---------------------------+---------+----------------------------------------------------+
- | shutdown-lock-limit | 0 | .. index:: |
- | | | pair: cluster option; shutdown-lock-limit |
- | | | |
- | | | If ``shutdown-lock`` is true, and this is set to a |
- | | | nonzero time duration, locked resources will be |
- | | | allowed to start after this much time has passed |
- | | | since the node shutdown was initiated, even if the |
- | | | node has not rejoined. (This works with remote |
- | | | nodes only if their connection resource's |
- | | | ``target-role`` is set to ``Stopped``.) |
- | | | *(since 2.0.4)* |
- +---------------------------+---------+----------------------------------------------------+
- | remove-after-stop | false | .. index:: |
- | | | pair: cluster option; remove-after-stop |
- | | | |
- | | | *Deprecated* Should the cluster remove |
- | | | resources from Pacemaker's executor after they are |
- | | | stopped? Values other than the default are, at |
- | | | best, poorly tested and potentially dangerous. |
- | | | This option is deprecated and will be removed in a |
- | | | future release. |
- +---------------------------+---------+----------------------------------------------------+
- | startup-fencing | true | .. index:: |
- | | | pair: cluster option; startup-fencing |
- | | | |
- | | | *Advanced Use Only:* Should the cluster fence |
- | | | unseen nodes at start-up? Setting this to false is |
- | | | unsafe, because the unseen nodes could be active |
- | | | and running resources but unreachable. |
- +---------------------------+---------+----------------------------------------------------+
- | election-timeout | 2min | .. index:: |
- | | | pair: cluster option; election-timeout |
- | | | |
- | | | *Advanced Use Only:* If you need to adjust this |
- | | | value, it probably indicates the presence of a bug.|
- +---------------------------+---------+----------------------------------------------------+
- | shutdown-escalation | 20min | .. index:: |
- | | | pair: cluster option; shutdown-escalation |
- | | | |
- | | | *Advanced Use Only:* If you need to adjust this |
- | | | value, it probably indicates the presence of a bug.|
- +---------------------------+---------+----------------------------------------------------+
- | join-integration-timeout | 3min | .. index:: |
- | | | pair: cluster option; join-integration-timeout |
- | | | |
- | | | *Advanced Use Only:* If you need to adjust this |
- | | | value, it probably indicates the presence of a bug.|
- +---------------------------+---------+----------------------------------------------------+
- | join-finalization-timeout | 30min | .. index:: |
- | | | pair: cluster option; join-finalization-timeout |
- | | | |
- | | | *Advanced Use Only:* If you need to adjust this |
- | | | value, it probably indicates the presence of a bug.|
- +---------------------------+---------+----------------------------------------------------+
- | transition-delay | 0s | .. index:: |
- | | | pair: cluster option; transition-delay |
- | | | |
- | | | *Advanced Use Only:* Delay cluster recovery for |
- | | | the configured interval to allow for additional or |
- | | | related events to occur. This can be useful if |
- | | | your configuration is sensitive to the order in |
- | | | which ping updates arrive. Enabling this option |
- | | | will slow down cluster recovery under all |
- | | | conditions. |
- +---------------------------+---------+----------------------------------------------------+
+ :widths: 2 2 2 5
+ :header-rows: 1
+
+ * - Name
+ - Type
+ - Default
+ - Description
+ * - .. _cluster_name:
+
+ .. index::
+ pair: cluster option; cluster-name
+
+ cluster-name
+ - :ref:`text `
+ -
+ - An (optional) name for the cluster as a whole. This is mostly for users'
+ convenience for use as desired in administration, but can be used in the
+ Pacemaker configuration in :ref:`rules` (as the ``#cluster-name``
+ :ref:`node attribute `). It may also
+ be used by higher-level tools when displaying cluster information, and
+ by certain resource agents (for example, the ``ocf:heartbeat:GFS2``
+ agent stores the cluster name in filesystem meta-data).
+ * - .. _dc_version:
+
+ .. index::
+ pair: cluster option; dc-version
+
+ dc-version
+ - :ref:`version `
+ - *detected*
+ - Version of Pacemaker on the cluster's designated controller (DC).
+ Maintained by the cluster, and intended for diagnostic purposes.
+ * - .. _cluster_infrastructure:
+
+ .. index::
+ pair: cluster option; cluster-infrastructure
+
+ cluster-infrastructure
+ - :ref:`text `
+ - *detected*
+ - The messaging layer with which Pacemaker is currently running.
+ Maintained by the cluster, and intended for informational and diagnostic
+ purposes.
+ * - .. _no_quorum_policy:
+
+ .. index::
+ pair: cluster option; no-quorum-policy
+
+ no-quorum-policy
+ - :ref:`enumeration `
+ - stop
+ - What to do when the cluster does not have quorum. Allowed values:
+
+ * ``ignore:`` continue all resource management
+ * ``freeze:`` continue resource management, but don't recover resources
+ from nodes not in the affected partition
+ * ``stop:`` stop all resources in the affected cluster partition
+ * ``demote:`` demote promotable resources and stop all other resources
+ in the affected cluster partition *(since 2.0.5)*
+ * ``suicide:`` fence all nodes in the affected cluster partition
+ * - .. _batch_limit:
+
+ .. index::
+ pair: cluster option; batch-limit
+
+ batch-limit
+ - :ref:`integer `
+ - 0
+ - The maximum number of actions that the cluster may execute in parallel
+ across all nodes. The ideal value will depend on the speed and load
+ of your network and cluster nodes. If zero, the cluster will impose a
+ dynamically calculated limit only when any node has high load. If -1,
+ the cluster will not impose any limit.
+ * - .. _migration_limit:
+
+ .. index::
+ pair: cluster option; migration-limit
+
+ migration-limit
+ - :ref:`integer `
+ - -1
+ - The number of :ref:`live migration ` actions that the
+ cluster is allowed to execute in parallel on a node. A value of -1 means
+ unlimited.
+ * - .. _symmetric_cluster:
+
+ .. index::
+ pair: cluster option; symmetric-cluster
+
+ symmetric-cluster
+ - :ref:`boolean `
+ - true
+ - If true, resources can run on any node by default. If false, a resource
+ is allowed to run on a node only if a
+ :ref:`location constraint ` enables it.
+ * - .. _stop_all_resources:
+
+ .. index::
+ pair: cluster option; stop-all-resources
+
+ stop-all-resources
+ - :ref:`boolean `
+ - false
+ - Whether all resources should be disallowed from running (can be useful
+ during maintenance or troubleshooting)
+ * - .. _stop_orphan_resources:
+
+ .. index::
+ pair: cluster option; stop-orphan-resources
+
+ stop-orphan-resources
+ - :ref:`boolean `
+ - true
+ - Whether resources that have been deleted from the configuration should
+ be stopped. This value takes precedence over
+ :ref:`is-managed ` (that is, even unmanaged resources will
+ be stopped when orphaned if this value is ``true``).
+ * - .. _stop_orphan_actions:
+
+ .. index::
+ pair: cluster option; stop-orphan-actions
+
+ stop-orphan-actions
+ - :ref:`boolean `
+ - true
+ - Whether recurring :ref:`operations ` that have been deleted
+ from the configuration should be cancelled
+ * - .. _start_failure_is_fatal:
+
+ .. index::
+ pair: cluster option; start-failure-is-fatal
+
+ start-failure-is-fatal
+ - :ref:`boolean `
+ - true
+ - Whether a failure to start a resource on a particular node prevents
+ further start attempts on that node. If ``false``, the cluster will
+ decide whether the node is still eligible based on the resource's
+ current failure count and ``migration-threshold``.
+ * - .. _enable_startup_probes:
+
+ .. index::
+ pair: cluster option; enable-startup-probes
+
+ enable-startup-probes
+ - :ref:`boolean `
+ - true
+ - Whether the cluster should check the pre-existing state of resources
+ when the cluster starts
+ * - .. _maintenance_mode:
+
+ .. index::
+ pair: cluster option; maintenance-mode
+
+ maintenance-mode
+ - :ref:`boolean `
+ - false
+ - If true, the cluster will not start or stop any resource in the cluster,
+ and any recurring operations (expect those specifying ``role`` as
+ ``Stopped``) will be paused. If true, this overrides the
+ :ref:`maintenance ` node attribute,
+ :ref:`is-managed ` and :ref:`maintenance `
+ resource meta-attributes, and :ref:`enabled ` operation
+ meta-attribute.
+ * - .. _stonith_enabled:
+
+ .. index::
+ pair: cluster option; stonith-enabled
+
+ stonith-enabled
+ - :ref:`boolean `
+ - true
+ - Whether the cluster is allowed to fence nodes (for example, failed nodes
+ and nodes with resources that can't be stopped).
+
+ If true, at least one fence device must be configured before resources
+ are allowed to run.
+
+ If false, unresponsive nodes are immediately assumed to be running no
+ resources, and resource recovery on online nodes starts without any
+ further protection (which can mean *data loss* if the unresponsive node
+ still accesses shared storage, for example). See also the
+ :ref:`requires ` resource meta-attribute.
+ * - .. _stonith_action:
+
+ .. index::
+ pair: cluster option; stonith-action
+
+ stonith-action
+ - :ref:`enumeration `
+ - reboot
+ - Action the cluster should send to the fence agent when a node must be
+ fenced. Allowed values are ``reboot``, ``off``, and (for legacy agents
+ only) ``poweroff``.
+ * - .. _stonith_timeout:
+
+ .. index::
+ pair: cluster option; stonith-timeout
+
+ stonith-timeout
+ - :ref:`duration `
+ - 60s
+ - How long to wait for ``on``, ``off``, and ``reboot`` fence actions to
+ complete by default.
+ * - .. _stonith_max_attempts:
+
+ .. index::
+ pair: cluster option; stonith-max-attempts
+
+ stonith-max-attempts
+ - :ref:`score `
+ - 10
+ - How many times fencing can fail for a target before the cluster will no
+ longer immediately re-attempt it. Any value below 1 will be ignored, and
+ the default will be used instead.
+ * - .. _stonith_watchdog_timeout:
+
+ .. index::
+ pair: cluster option; stonith-watchdog-timeout
+
+ stonith-watchdog-timeout
+ - :ref:`timeout `
+ - 0
+ - If nonzero, and the cluster detects ``have-watchdog`` as ``true``, then
+ watchdog-based self-fencing will be performed via SBD when fencing is
+ required, without requiring a fencing resource explicitly configured.
+
+ If this is set to a positive value, unseen nodes are assumed to
+ self-fence within this much time.
+
+ **Warning:** It must be ensured that this value is larger than the
+ ``SBD_WATCHDOG_TIMEOUT`` environment variable on all nodes. Pacemaker
+ verifies the settings individually on all nodes and prevents startup or
+ shuts down if configured wrongly on the fly. It is strongly recommended
+ that ``SBD_WATCHDOG_TIMEOUT`` be set to the same value on all nodes.
+
+ If this is set to a negative value, and ``SBD_WATCHDOG_TIMEOUT`` is set,
+ twice that value will be used.
+
+ **Warning:** In this case, it is essential (and currently not verified
+ by pacemaker) that ``SBD_WATCHDOG_TIMEOUT`` is set to the same value on
+ all nodes.
+ * - .. _concurrent-fencing:
+
+ .. index::
+ pair: cluster option; concurrent-fencing
+
+ concurrent-fencing
+ - :ref:`boolean `
+ - false
+ - Whether the cluster is allowed to initiate multiple fence actions
+ concurrently. Fence actions initiated externally, such as via the
+ ``stonith_admin`` tool or an application such as DLM, or by the fencer
+ itself such as recurring device monitors and ``status`` and ``list``
+ commands, are not limited by this option.
+ * - .. _fence_reaction:
+
+ .. index::
+ pair: cluster option; fence-reaction
+
+ fence-reaction
+ - :ref:`enumeration `
+ - stop
+ - How should a cluster node react if notified of its own fencing? A
+ cluster node may receive notification of its own fencing if fencing is
+ misconfigured, or if fabric fencing is in use that doesn't cut cluster
+ communication. Allowed values are ``stop`` to attempt to immediately
+ stop Pacemaker and stay stopped, or ``panic`` to attempt to immediately
+ reboot the local node, falling back to stop on failure. The default is
+ likely to be changed to ``panic`` in a future release. *(since 2.0.3)*
+ * - .. _priority_fencing_delay:
+
+ .. index::
+ pair: cluster option; priority-fencing-delay
+
+ priority-fencing-delay
+ - :ref:`duration `
+ - 0
+ - Apply this delay to any fencing 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 (especially meaningful in a
+ split-brain of a 2-node cluster). A promoted resource instance takes the
+ resource's priority plus 1 if the resource's priority is not 0. Any
+ static or random delays introduced by ``pcmk_delay_base`` and
+ ``pcmk_delay_max`` configured for the corresponding fencing resources
+ will be added to this delay. This delay should be significantly greater
+ than (safely twice) the maximum delay from those parameters. *(since
+ 2.0.4)*
+ * - .. _node_pending_timeout:
+
+ .. index::
+ pair: cluster option; node-pending-timeout
+
+ node-pending-timeout
+ - :ref:`duration `
+ - 2h
+ - Fence nodes that do not join the controller process group within this
+ much time after joining the cluster, to allow the cluster to continue
+ managing resources. A value of 0 means never fence pending nodes.
+ *(since 2.1.7)*
+ * - .. _cluster_delay:
+
+ .. index::
+ pair: cluster option; cluster-delay
+
+ cluster-delay
+ - :ref:`duration `
+ - 60s
+ - If the DC requires an action to be executed on another node, it will
+ consider the action failed if it does not get a response from the other
+ node within this time (beyond the action's own timeout). The ideal value
+ will depend on the speed and load of your network and cluster nodes.
+ * - .. _dc_deadtime:
+
+ .. index::
+ pair: cluster option; dc-deadtime
+
+ dc-deadtime
+ - :ref:`duration `
+ - 20s
+ - How long to wait for a response from other nodes when electing a DC. The
+ ideal value will depend on the speed and load of your network and
+ cluster nodes.
+ * - .. _cluster_ipc_limit:
+
+ .. index::
+ pair: cluster option; cluster-ipc-limit
+
+ cluster-ipc-limit
+ - :ref:`nonnegative integer `
+ - 500
+ - The maximum IPC message backlog before one cluster daemon will
+ disconnect another. This is of use in large clusters, for which a good
+ value is the number of resources in the cluster multiplied by the number
+ of nodes. The default of 500 is also the minimum. Raise this if you see
+ "Evicting client" log messages for cluster daemon process IDs.
+ * - .. _pe_error_series_max:
+
+ .. index::
+ pair: cluster option; pe-error-series-max
+
+ pe-error-series-max
+ - :ref:`integer `
+ - -1
+ - The number of scheduler inputs resulting in errors to save. These inputs
+ can be helpful during troubleshooting and when reporting issues. A
+ negative value means save all inputs, and 0 means save none.
+ * - .. _pe_warn_series_max:
+
+ .. index::
+ pair: cluster option; pe-warn-series-max
+
+ pe-warn-series-max
+ - :ref:`integer `
+ - 5000
+ - The number of scheduler inputs resulting in warnings to save. These
+ inputs can be helpful during troubleshooting and when reporting issues.
+ A negative value means save all inputs, and 0 means save none.
+ * - .. _pe_input_series_max:
+
+ .. index::
+ pair: cluster option; pe-input-series-max
+
+ pe-input-series-max
+ - :ref:`integer `
+ - 4000
+ - The number of "normal" scheduler inputs to save. These inputs can be
+ helpful during troubleshooting and when reporting issues. A negative
+ value means save all inputs, and 0 means save none.
+ * - .. _enable_acl:
+
+ .. index::
+ pair: cluster option; enable-acl
+
+ enable-acl
+ - :ref:`boolean `
+ - false
+ - Whether :ref:`access control lists ` should be used to authorize
+ CIB modifications
+ * - .. _placement_strategy:
+
+ .. index::
+ pair: cluster option; placement-strategy
+
+ placement-strategy
+ - :ref:`enumeration `
+ - default
+ - How the cluster should assign resources to nodes (see
+ :ref:`utilization`). Allowed values are ``default``, ``utilization``,
+ ``balanced``, and ``minimal``.
+ * - .. _node_health_strategy:
+
+ .. index::
+ pair: cluster option; node-health-strategy
+
+ node-health-strategy
+ - :ref:`enumeration `
+ - none
+ - How the cluster should react to :ref:`node health `
+ attributes. Allowed values are ``none``, ``migrate-on-red``,
+ ``only-green``, ``progressive``, and ``custom``.
+ * - .. _node_health_base:
+
+ .. index::
+ pair: cluster option; node-health-base
+
+ node-health-base
+ - :ref:`score `
+ - 0
+ - The base health score assigned to a node. Only used when
+ ``node-health-strategy`` is ``progressive``.
+ * - .. _node_health_green:
+
+ .. index::
+ pair: cluster option; node-health-green
+
+ node-health-green
+ - :ref:`score `
+ - 0
+ - The score to use for a node health attribute whose value is ``green``.
+ Only used when ``node-health-strategy`` is ``progressive`` or
+ ``custom``.
+ * - .. _node_health_yellow:
+
+ .. index::
+ pair: cluster option; node-health-yellow
+
+ node-health-yellow
+ - :ref:`score `
+ - 0
+ - The score to use for a node health attribute whose value is ``yellow``.
+ Only used when ``node-health-strategy`` is ``progressive`` or
+ ``custom``.
+ * - .. _node_health_red:
+
+ .. index::
+ pair: cluster option; node-health-red
+
+ node-health-red
+ - :ref:`score `
+ - 0
+ - The score to use for a node health attribute whose value is ``red``.
+ Only used when ``node-health-strategy`` is ``progressive`` or
+ ``custom``.
+ * - .. _cluster_recheck_interval:
+
+ .. index::
+ pair: cluster option; cluster-recheck-interval
+
+ cluster-recheck-interval
+ - :ref:`duration `
+ - 15min
+ - Pacemaker is primarily event-driven, and looks ahead to know when to
+ recheck the cluster for failure timeouts and most time-based rules
+ *(since 2.0.3)*. However, it will also recheck the cluster after this
+ amount of inactivity. This has two goals: rules with ``date_spec`` are
+ only guaranteed to be checked this often, and it also serves as a
+ fail-safe for some kinds of scheduler bugs. A value of 0 disables this
+ polling.
+ * - .. _shutdown_lock:
+
+ .. index::
+ pair: cluster option; shutdown-lock
+
+ shutdown-lock
+ - :ref:`boolean `
+ - false
+ - The default of false allows active resources to be recovered elsewhere
+ when their node is cleanly shut down, which is what the vast majority of
+ users will want. However, some users prefer to make resources highly
+ available only for failures, with no recovery for clean shutdowns. If
+ this option is true, resources active on a node when it is cleanly shut
+ down are kept "locked" to that node (not allowed to run elsewhere) until
+ they start again on that node after it rejoins (or for at most
+ ``shutdown-lock-limit``, if set). Stonith resources and Pacemaker Remote
+ connections are never locked. Clone and bundle instances and the
+ promoted role of promotable clones are currently never locked, though
+ support could be added in a future release. Locks may be manually
+ cleared using the ``--refresh`` option of ``crm_resource`` (both the
+ resource and node must be specified; this works with remote nodes if
+ their connection resource's ``target-role`` is set to ``Stopped``, but
+ not if Pacemaker Remote is stopped on the remote node without disabling
+ the connection resource). *(since 2.0.4)*
+ * - .. _shutdown_lock_limit:
+
+ .. index::
+ pair: cluster option; shutdown-lock-limit
+
+ shutdown-lock-limit
+ - :ref:`duration `
+ - 0
+ - If ``shutdown-lock`` is true, and this is set to a nonzero time
+ duration, locked resources will be allowed to start after this much time
+ has passed since the node shutdown was initiated, even if the node has
+ not rejoined. (This works with remote nodes only if their connection
+ resource's ``target-role`` is set to ``Stopped``.) *(since 2.0.4)*
+ * - .. _remove_after_stop:
+
+ .. index::
+ pair: cluster option; remove-after-stop
+
+ remove-after-stop
+ - :ref:`boolean `
+ - false
+ - *Deprecated* Whether the cluster should remove resources from
+ Pacemaker's executor after they are stopped. Values other than the
+ default are, at best, poorly tested and potentially dangerous. This
+ option is deprecated and will be removed in a future release.
+ * - .. _startup_fencing:
+
+ .. index::
+ pair: cluster option; startup-fencing
+
+ startup-fencing
+ - :ref:`boolean `
+ - true
+ - *Advanced Use Only:* Whether the cluster should fence unseen nodes at
+ start-up. Setting this to false is unsafe, because the unseen nodes
+ could be active and running resources but unreachable. ``dc-deadtime``
+ acts as a grace period before this fencing, since a DC must be elected
+ to schedule fencing.
+ * - .. _election_timeout:
+
+ .. index::
+ pair: cluster option; election-timeout
+
+ election-timeout
+ - :ref:`duration `
+ - 2min
+ - *Advanced Use Only:* If a winner is not declared within this much time
+ of starting an election, the node that initiated the election will
+ declare itself the winner.
+ * - .. _shutdown_escalation:
+
+ .. index::
+ pair: cluster option; shutdown-escalation
+
+ shutdown-escalation
+ - :ref:`duration `
+ - 20min
+ - *Advanced Use Only:* The controller will exit immediately if a shutdown
+ does not complete within this much time.
+ * - .. _join_integration_timeout:
+
+ .. index::
+ pair: cluster option; join-integration-timeout
+
+ join-integration-timeout
+ - :ref:`duration `
+ - 3min
+ - *Advanced Use Only:* If you need to adjust this value, it probably
+ indicates the presence of a bug.
+ * - .. _join_finalization_timeout:
+
+ .. index::
+ pair: cluster option; join-finalization-timeout
+
+ join-finalization-timeout
+ - :ref:`duration `
+ - 30min
+ - *Advanced Use Only:* If you need to adjust this value, it probably
+ indicates the presence of a bug.
+ * - .. _transition_delay:
+
+ .. index::
+ pair: cluster option; transition-delay
+
+ transition-delay
+ - :ref:`duration `
+ - 0s
+ - *Advanced Use Only:* Delay cluster recovery for the configured interval
+ to allow for additional or related events to occur. This can be useful
+ if your configuration is sensitive to the order in which ping updates
+ arrive. Enabling this option will slow down cluster recovery under all
+ conditions.