Difference between revisions of "Heat/Blueprints/ScalableResourceGroup"
| Line 33: | Line 33: | ||
== Design == | == Design == | ||
Define a new heat resource type: OS::HEAT::ScalableResourceGroup with the following properties: | Define a new heat resource type: OS::HEAT::ScalableResourceGroup with the following properties: | ||
| − | + | resource_def : Map | |
Resource definition for the resources in the group. | Resource definition for the resources in the group. | ||
Required property. | Required property. | ||
Can be updated without replacement. | Can be updated without replacement. | ||
| − | + | index_var : String | |
A variable that this resource will use to replace with the current index of a given resource in the group. | A variable that this resource will use to replace with the current index of a given resource in the group. | ||
Updates cause replacement. | Updates cause replacement. | ||
Optional property, defaults to “%index%”. | Optional property, defaults to “%index%”. | ||
| − | + | initial_size: Integer | |
Initial number of resources in the group at creation time. | Initial number of resources in the group at creation time. | ||
| − | Optional property | + | Optional property, defaults to 1. |
| − | |||
| − | + | max_size: Integer | |
Maximum number of resources in the group. | Maximum number of resources in the group. | ||
| − | Optional Property | + | Optional Property, defaults to 1. |
| − | Updates can cause creation/deletion of some resources according to | + | Updates can cause creation/deletion of some resources according to scale_in_criteria/scale_in_order. |
| − | + | min_size: Integer | |
| − | + | Minimum number of resources in the group. | |
| − | Optional property. | + | Optional property, defaults to 1. |
| − | Updates can cause | + | Updates can cause addition/removal of resources according to scale_in_criteria/scale_in_order. |
| − | + | scale_in_criteria:String | |
Specifies criteria for removal of resources form the group. | Specifies criteria for removal of resources form the group. | ||
| − | Optional property. | + | Optional property, defaults to "Index". |
Possible Values: "Index" or "Age" | Possible Values: "Index" or "Age" | ||
Default: "Index" | Default: "Index" | ||
| − | + | scale_in_order:String | |
Specifies order for removal of resources form the group according to the specified criteria. | Specifies order for removal of resources form the group according to the specified criteria. | ||
| − | Optional property. | + | Optional property, defaults to "Decreasing". |
Possible Values: "Increasing" or "Decreasing" | Possible Values: "Increasing" or "Decreasing" | ||
Default: "Decreasing" | Default: "Decreasing" | ||
Revision as of 15:26, 10 August 2015
< Heat
Launchpad Entry: HeatSpec:ScalableResourceGroup
Created: 26 July 2015
Contributors: Ahmed El-Khouly
Summary
OS::Heat::ResourceGroup provides a way to create several instances of identically configured nested resource; resources within the group can be addressed with their resource index.
OS::Heat::ResourceGroup can only scale by changing the count property followed by a stack update of the root stack.
OS::Heat::AutoScalingGroup/Policy also provide a way to create several instances identically configured nested resources with the added ability of changing size(scale) when the accompanying AutoScalingPolicy receives a signal. Auto-scaling policy defines characteristics of the scale operation (size of adjustment, size of adjustment, cool down period).
Some cloud applications need a resource group type that can change size and with the added ability of removal or addition of specific resources.
Release Note
TBD
Rationale
Some cloud applications need a new resource group with the following features:
1) Create an initial number of identically configured nested resources.
2) Address single resource within the group using the index with the ability to specify a variable to be replaced by the index.
3) Add(Remove) specific resource within the group by specifying the indices of involved resources.
4) Scale out(in) by adjusting the group size (with a certain increment) when user defined triggers are met.
User Stories
1) Recreate a (failed) resource by adding/deleting the corresponding nested resource in the group.
2) Add new resources to group when certain criteria met(ex. increase in workload).
3) Remove a number of resources according to a predefined criteria(increasing or decreasing order of age or index).
4) Specify certain resources for removal.
Assumptions
None.
Design
Define a new heat resource type: OS::HEAT::ScalableResourceGroup with the following properties:
resource_def : Map Resource definition for the resources in the group. Required property. Can be updated without replacement.
index_var : String A variable that this resource will use to replace with the current index of a given resource in the group. Updates cause replacement. Optional property, defaults to “%index%”.
initial_size: Integer Initial number of resources in the group at creation time. Optional property, defaults to 1.
max_size: Integer Maximum number of resources in the group. Optional Property, defaults to 1. Updates can cause creation/deletion of some resources according to scale_in_criteria/scale_in_order.
min_size: Integer Minimum number of resources in the group. Optional property, defaults to 1. Updates can cause addition/removal of resources according to scale_in_criteria/scale_in_order.
scale_in_criteria:String Specifies criteria for removal of resources form the group. Optional property, defaults to "Index". Possible Values: "Index" or "Age" Default: "Index"
scale_in_order:String Specifies order for removal of resources form the group according to the specified criteria. Optional property, defaults to "Decreasing". Possible Values: "Increasing" or "Decreasing" Default: "Decreasing"
ScalableResourceGroup class inherits from ResourceGroup:
- Provide handle_signal implementation to receive signals to add/delete and grow/degrow signals. - Override create/validate/update/delete handlers.
