Use this page to view properties of the dependency that
you selected to view from those dependencies that are
defined for the cluster.
Dependencies between resource groups allow complex clusters that
use multi-tiered applications to be managed predictably and reliably.
There are five different types of dependencies that can be defined
among resource groups within a cluster:
- Parent-Child
- Start After
- Stop After
- Online on Same Node
- Online on Different Nodes
What properties you can view depend on the type of dependency
that you select from those dependencies that are defined for the cluster.
Parent-Child Fields
In this type of dependency,
during resource group acquisition, the parent resource group on a
node is acquired before the children resource groups are acquired.
During resource group release, children resource groups are released
before the parent resource group is released. The parent resource
group must be online on any node in the cluster before children (dependent)
resource groups can be activated on a node.
- Associated resource groups
- Displays all resource groups that are defined for the selected
dependency.
- Parent resource group
- Displays the name of the parent resource group that provides services
upon which a one or more child resource groups depend.
- Child resource group
- Displays the name of the child resource groups that depend on
services that the parent resource group provides.
Start After Fields
In this type of dependency,
during resource group acquisition, the target resource group on a
node is acquired before the dependent resource group is acquired.
The target resource group must be online on any node in the cluster
before the dependent resource group can be activated on a node.
- Associated resource groups
- Displays all resource groups that are defined for the selected
dependency.
- Target Resource Group
- Displays the name of the target resource group that provides services
upon which another resource group depends.
- Resource group to start after the target resource group
- Displays the name of the resource group that is to start after
the target resource group starts.
Stop After Fields
In this type of dependency,
during resource group release, the target resource group on a node
is released before the dependent resource group is released.
- Associated resource groups
- Displays all resource groups that are defined for the selected
dependency.
- Target Resource Group
- Displays the name of the target resource group that provides
services upon which another resource group depends.
- Resource groups to stop after the target resource group
- Displays the name of the resource group that is to stop after
the target resource group stops.
Online on Same Node Fields
In this type
of dependency, a set of two or more resource groups are acquired and
brought online on the same node according to the startup policy and
the availability of the node required. On fallback and fallover, the
set of resource groups are processed simultaneously and brought online
on the same target node using the fallover and fallback policy defined
for these groups.
- Associated resource groups
- Displays all resource groups that are defined for the selected
dependency.
- Resource groups to be online in the same node
- Displays the names of the resource groups to be acquired and brought
online on the same node.
Online on Different Nodes Fields
In this
type of dependency, sets of resource groups are assigned High, Medium,
and Low priority values, which are used in case there is contention
for a given node at any point in time. Higher priority resource groups
take precedence over lower priority groups at startup, fallover, and
fallback. Each resource group in a set must have a different home
node for startup. Only one Online On Different Nodes Dependency
set is allowed per cluster.
- Associated resource groups
- Displays all resource groups that are defined for the selected
dependency.
- High priority resource groups
- Displays the names of the resource groups, in priority order,
that are to be acquired and brought online before lower priority resource
groups.
- Medium priority
- Displays the names of the resource groups that are to be acquired
and brought online after the high priority resource groups and before
low priority resource groups are brought online.
- Selected low priority
- Displays the names of the resource groups that are to be acquired
and brought online after any higher priority or medium priority resource
groups are brought online