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:.
A mapping of host names to port numbers for devices that do not support host names. For example: node;node,3 tells the cluster to use port 1 for node1 and ports 2 and 3 for node2.
How to determine which machines are controlled by the device. The following table summarizes additional properties you can set for fencing devices.
Note that these properties are for advanced use only. 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 none can be used to tell the cluster not to supply any additional parameters.
An alternate command to run instead of reboot. Some devices do not support the standard commands or may provide additional ones. Use this to specify an alternate, device-specific, command that implements the reboot action.
Specify an alternate timeout to use for reboot actions instead of stonith-timeout. Use this to specify an alternate, device-specific, timeout for reboot actions. The maximum number of times to retry the reboot 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 reboot actions before giving up. An alternate command to run instead of off. Use this to specify an alternate, device-specific, command that implements the off action. Specify an alternate timeout to use for off actions instead of stonith-timeout.
Some devices need much more or much less time to complete than normal. Use this to specify an alternate, device-specific, timeout for off actions. The maximum number of times to retry the off command within the timeout period. Use this option to alter the number of times Pacemaker retries off actions before giving up. An alternate command to run instead of list. Use this to specify an alternate, device-specific, command that implements the list action.
Specify an alternate timeout to use for list actions. Use this to specify an alternate, device-specific, timeout for list actions. The maximum number of times to retry the list command within the timeout period. Use this option to alter the number of times Pacemaker retries list actions before giving up.
An alternate command to run instead of monitor. Use this to specify an alternate, device-specific, command that implements the monitor action. Specify an alternate timeout to use for monitor actions instead of stonith-timeout.
Use this to specify an alternate, device-specific, timeout for monitor actions. The maximum number of times to retry the monitor command within the timeout period. Use this option to alter the number of times Pacemaker retries monitor actions before giving up. An alternate command to run instead of status. Use this to specify an alternate, device-specific, command that implements the status action.
Specify an alternate timeout to use for status actions instead of stonith-timeout. Use this to specify an alternate, device-specific, timeout for status actions.
The maximum number of times to retry the status command within the timeout period. Use this option to alter the number of times Pacemaker retries status actions before giving up. Enable a base delay for stonith actions and specify a base delay value. In a cluster with an even number of nodes, configuring a delay can help avoid nodes fencing each other at the same time in an even split. A random delay can be useful when the same fence device is used for all nodes, and differing static delays can be useful on each fencing device when a separate device is used for each node.
The overall delay is derived from a random delay value adding this static delay so that the sum is kept below the maximum delay. If both of these delays are configured, they are added together and thus would generally not be used in conjunction. Enable a random delay for stonith actions and specify the maximum of random delay. The overall delay is derived from this random delay value adding a static delay so that the sum is kept below the maximum delay.
The maximum number of actions that can be performed in parallel on this device. A value of -1 is unlimited. For advanced use only: An alternate command to run instead of on. Use this to specify an alternate, device-specific, command that implements the on action. For advanced use only: Specify an alternate timeout to use for on actions instead of stonith-timeout.
Use this to specify an alternate, device-specific, timeout for on actions. For advanced use only: The maximum number of times to retry the on command within the timeout period. Use this option to alter the number of times Pacemaker retries on actions before giving up. 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. Indicates that failed nodes and nodes with resources that cannot be stopped should be fenced.
Protecting your data requires that you set this true. Red Hat only supports clusters with this value set to true. Allowed values: reboot , off. For example:. This will also run additional validation. It is necessary that ricci be running in each cluster node to be able to propagate updated cluster configuration information. Proceed to Section 8. If required, you can configure complex configurations with multiple fence methods per node and with multiple fence devices per fence method.
When specifying multiple fence methods per node, if fencing fails using the first method, fenced , the fence daemon, tries the next method, and continues to cycle through methods until one succeeds.
This is done by specifying two or more devices within a fence method. Fencing Configuration Examples. The following examples show a simple configuration with one fence method per node and one fence device per fence method:.
The examples in this section are not exhaustive; that is, there may be other ways to configure fencing depending on your requirements. The fencing agent, in turn, fences the node by means of a fencing device. When fencing is complete, the fencing program notifies the cluster manager. Power fencing — A fencing method that uses a power controller to power off an inoperable node. Figure 4. In the example, the fencing program in node A causes the power controller to power off node D.
In the example, the fencing program in node A causes the Fibre Channel switch to disable the port for node D, disconnecting node D from storage. Specifying a fencing method consists of editing a cluster configuration file to assign a fencing-method name, the fencing agent, and the fencing device for each node in the cluster.
The way in which a fencing method is specified depends on if a node has either dual power supplies or multiple paths to storage.
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