Allocation Rules
Allocation rules are used in the horizontal cluster to determine which primary node a new clustered resource should be allocated to. When a new clustered resource is created, the Cluster Coordinator evaluates the Condition expression of each allocation rule sequentially, starting at the top, until a condition evaluates to True
. In this case, the corresponding Expression is evaluated. The resource is allocated to the node matching the server ID produced by the Expression. If the evaluation does not result in a valid server ID, the resource is allocated according to a round robin strategy.
Field Description | Field Name | ||
Name. Allocation rule name. | name | ||
Expression. The expression defines the logic for determining which primary node should be allocated for a new resource. Must return a valid Server ID. | Expression Expression Resolution Environment: | expression | |
Data table with a single field | |||
Root context of the Cluster Coordinator | |||
0 | |||
Standard variables only. | |||
Condition: The condition property specifies additional criteria that must be met for an allocation rule to be applied. If the condition evaluates to | Condition Expression Resolution Environment: | condition | |
Data table with a single field | |||
Root context of the Cluster Coordinator | |||
0 | |||
Standard variables only. | |||
Comment. Adds comments or notes about the allocation rule for documentation or reference purposes. | comment |
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