Use this task to manage and view the relationships (dependencies)
among the resource groups within the selected cluster.
Dependencies between resource groups allow complex clusters that
use multi-tired applications to be managed predictably and reliably.
You can configure five types of dependencies among resource groups
within a cluster:
- Parent-Child
- Online on Same Site
- Start After
- Stop After
- Online on Same Node
- Online on Different Nodes
Parent-Child
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.
- Parent resource group
- Select the parent resource group from the list. The parent resource
group provides services upon which a child resource group depends.
- Child resource group
- Select one or more child resource groups from the list. The child
resource group depends on services that the parent resource group
provides.
Online on same site
In this type of dependency,
a location policy is established so that the selected resource groups
are started and remains online on the same site.
- Name
- Indicates the name of the resource group.
- HA Status
- Indicates the status of the resource group.
- Participating Nodes
- Indicates the nodes that are part of the resource group.
Start After
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.
- Target Resource Group
- Select the target resource group from the list. The target resource
group provides services upon which another resource group depends.
- Resource group to start after the target resource group
- Select the resource group from the list that you want to start
after the target resource group starts.
Stop After
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.
- Target Resource Group
- Select the target resource group from the list. The target resource
group provides services upon which another resource group depends.
- Resource groups to stop after the target resource group
- Select the resource group from the list that you want to stop
after the target resource group stops.
Online on Same Node
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.
- Resource groups to be online in the same node
- Select two or more resource groups from the list to be acquired
and brought online on the same node.
Online on Different Nodes
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.
- Available resource groups
- Available resource groups lists all discovered
resource groups within the selected cluster that are available for
this type of dependency. Select a resource group in the list, then
click the > associated with the appropriate
priority value to move the resource group to that priority list. Select
resource groups in order of priority for handling failover in case
of a node failure. You must select at least two resource groups.
- High priority
- Select one or more resource groups from the Available
resource groups list to move to the High priority list.
Resource groups in this list are to be acquired and brought online
before lower priority resource groups.
- Medium priority
- Select one or more resource groups from the Available
resource groups list to move to the Medium
priority list. Resource groups in this list are to be
acquired and brought online after the high priority groups and before
low priority resource groups are brought online.
- Selected low priority
- Select one or more resource groups from the Available
resource groups list to move to the Low priority list.
Resource groups in this list are to be acquired and brought online
after any higher priority or medium priority resource groups are brought
online.