9.3. General properties of fencing devices
There are many general properties you can set for fencing devices, as well as various cluster properties that determine fencing behavior.
Any cluster node can fence any other cluster node with any fence device, regardless of whether the fence resource is started or stopped. Whether the resource is started controls only the recurring monitor for the device, not whether it can be used, with the following exceptions:
-
You can disable a fencing device by running the
pcs stonith disable stonith_idcommand. This will prevent any node from using that device. -
To prevent a specific node from using a fencing device, you can configure location constraints for the fencing resource with the
pcs constraint location … avoidscommand. -
Configuring
stonith-enabled=falsewill disable fencing altogether. Note, however, that Red Hat does not support clusters when fencing is disabled, as it is not suitable for a production environment.
The following table describes the general properties you can set for fencing devices.
| Field | Type | Default | Description |
|---|---|---|---|
|
| string |
A mapping of host names to port numbers for devices that do not support host names. For example: | |
|
| string |
A list of machines controlled by this device (Optional unless | |
|
| string |
*
* Otherwise,
* Otherwise,
*Otherwise, |
How to determine which machines are controlled by the device. Allowed values: |
The following table summarizes additional properties you can set for fencing devices. Note that these properties are for advanced use only.
| Field | Type | Default | Description |
|---|---|---|---|
|
| string | port |
An alternate parameter to supply instead of port. Some devices do not support the standard port parameter or may provide additional ones. Use this to specify an alternate, device-specific parameter that should indicate the machine to be fenced. A value of |
|
| string | reboot |
An alternate command to run instead of |
|
| time | 60s |
Specify an alternate timeout to use for reboot actions instead of |
|
| integer | 2 |
The maximum number of times to retry the |
|
| string | off |
An alternate command to run instead of |
|
| time | 60s |
Specify an alternate timeout to use for off actions instead of |
|
| integer | 2 | The maximum number of times to retry the off command within the timeout period. Some devices do not support multiple connections. Operations may fail if the device is busy with another task so Pacemaker will automatically retry the operation, if there is time remaining. Use this option to alter the number of times Pacemaker retries off actions before giving up. |
|
| string | list |
An alternate command to run instead of |
|
| time | 60s | Specify an alternate timeout to use for list actions. Some devices need much more or much less time to complete than normal. Use this to specify an alternate, device-specific, timeout for list actions. |
|
| integer | 2 |
The maximum number of times to retry the |
|
| string | monitor |
An alternate command to run instead of |
|
| time | 60s |
Specify an alternate timeout to use for monitor actions instead of |
|
| integer | 2 |
The maximum number of times to retry the |
|
| string | status |
An alternate command to run instead of |
|
| time | 60s |
Specify an alternate timeout to use for status actions instead of |
|
| integer | 2 | The maximum number of times to retry the status command within the timeout period. Some devices do not support multiple connections. Operations may fail if the device is busy with another task so Pacemaker will automatically retry the operation, if there is time remaining. Use this option to alter the number of times Pacemaker retries status actions before giving up. |
|
| string | 0s |
Enables a base delay for fencing actions and specifies a base delay value. You can specify different values for different nodes with the |
|
| time | 0s |
Enables a random delay for fencing actions and specifies the maximum delay, which is the maximum value of the combined base delay and random delay. For example, if the base delay is 3 and |
|
| integer | 1 |
The maximum number of actions that can be performed in parallel on this device. The cluster property |
|
| string | on |
For advanced use only: An alternate command to run instead of |
|
| time | 60s |
For advanced use only: Specify an alternate timeout to use for |
|
| integer | 2 |
For advanced use only: The maximum number of times to retry the |
In addition to the properties you can set for individual fence devices, there are also cluster properties you can set that determine fencing behavior, as described in the following table.
| Option | Default | Description |
|---|---|---|
|
| true |
Indicates that failed nodes and nodes with resources that cannot be stopped should be fenced. Protecting your data requires that you set this
If
Red Hat only supports clusters with this value set to |
|
| reboot |
Action to send to fencing device. Allowed values: |
|
| 60s | How long to wait for a STONITH action to complete. |
|
| 10 | How many times fencing can fail for a target before the cluster will no longer immediately re-attempt it. |
|
| The maximum time to wait until a node can be assumed to have been killed by the hardware watchdog. It is recommended that this value be set to twice the value of the hardware watchdog timeout. This option is needed only if watchdog-only SBD configuration is used for fencing. | |
|
| true | Allow fencing operations to be performed in parallel. |
|
| stop |
Determines how a cluster node should 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 does not cut cluster communication. Allowed values are
Although the default value for this property is |
|
| 0 (disabled) | Sets a fencing delay that allows you to configure a two-node cluster so that in a split-brain situation the node with the fewest or least important resources running is the node that gets fenced. For general information about fencing delay parameters and their interactions, see Fencing delays. |
For information about setting cluster properties, see Setting and removing cluster properties.