Cartridge Group Resource Definition

A cartridge group defines the relationship among a set of cartridge groups and a set of cartridges. The relationship among the children of a group can be the startup order, termination behavior and any scalable dependencies. Writing a cartridge group definition provides the ability to re-use the same frequently used cartridges as needed in different composite applications. The cartridges that correspond to a cartridge group have to be added to WSO2 Private PaaS before the cartridge group is added. A sample cartridge group definition, together with information on all the properties that can be added in a cartridge group definition JSON are as follows:

Sample cartridge group definition JSON

The following are sample configurations that can be used in a JSON to define a cartridge group:

{
  "name": "esb-php-group",
  "cartridges": [
    "esb",
    "php"
  ],
  "dependencies": {
    "startupOrders": [
      {
        "aliases": [
          "cartridge.my-esb",
          "cartridge.my-php"
        ]
      }
    ],
    "terminationBehaviour": "terminate-none"
  }
}

Property definitions

All the properties that correspond to the cartridge group resource are explained as follows:

name
groups
- name
- groups
- cartridges
- dependencies
cartridges
dependencies

W = Writable

R = Readable

U = Updatable

M = Mandatory (Required)

DV = Default Value

Main property definitions

Property		W	R	U	Description	M	DV	Data Type	Example
JSON	UI	W	R	U	Description	M	DV	Data Type	Example
`name`	Group Name	√	√		The name of the group.	Yes	N/A	String	group 1
`groups`	groups	√	√		Defines all other nested groups within the group.			groups array
`cartridges`	cartridges	√	√		If the group refers to any cartridges, then such details needs to be mentioned under this parameter. When defining cartridges, you need to use the name of the cartridge.	Yes	N/A	cartridges array	tomcat, php
`dependencies`	Dependencies	√	√		Defines the dependency that exists between members (cartridge or a group). For more information on the sub-properties, see dependencies.	Yes	N/A	dependencies

Sub-property definitions

dependencies

Property		W	R	U	Description	M	DV	Data Type	Example
JSON	UI	W	R	U	Description	M	DV	Data Type	Example
`startupOrders`	Startup Orders	√	√		The order in which the group’s children (sub groups and cartridges) need to started up. If it is a group, it should use the format of `"group.<GROUP_ALIAS>"` and if it is a cartridge, it should be `"cartridge.<CARTRIDGE_ALIAS>"` when defining `startupOrder`. Multiple startupOrders can also be defined as String array. However, the `startupOrder` should not create a cyclic dependency. By defining multiple `startupOrders`, parallel dependencies can be identified to start them in parallel. If the `startupOrder` is as follows, `group3`, `group1` should come before `tomcat` and `php`. However, `tomcat` or `php` can come up in any order. "startupOrders": [ { "aliases": [ "group.group3", "cartridge.tomcat" ] }, { "aliases": [ "group.group1", "cartridge.php" ] } ], If the startupOrder is as follows, then group1 will come up first, then `tomcat` and then `php`. "startupOrders": [ { "aliases":[ "group.group1", "cartridge.tomcat", "cartridge.php" ] } ], If the startupOrder has two independent rules defined as follows, then once `group1` is brought up, `tomcat` and `php` can be brought up in parallel. "startupOrders": [ { "aliases": [ "group.group1", "cartridge.tomcat" ] }, { "aliases": [ "group.group1", "cartridge.php" ] } ], If a startupOrder is not defined then the groups or cartridges will be started up parallel to each other.	No	N/A	startupOrders array	group.group1, cartridge.tomcat
`terminationBehaviour`	Termination Behaviour	√	√		This determines how the instances need to be terminated. The following is the example startupOrder used to explain the terminationBehaviour: "startupOrders": [ { "aliases": [ "group.group1", "cartridge.tomcat" ] }, { "aliases": [ "group.group1", "cartridge.php" ] } ], The available terminationBehaviours are as follows: `terminate-none`None of the children in a group will be terminated. For example, if something happens to `group1`, it will not have an impact on tomcat or php. `terminate-all` All the elements in that dependency tree will be terminated. For example, if something happens to `php`, then all the children of the group that `php` belongs to, will be get terminated regardless of the other dependency information. Note that cartridges and sub-groups are considered as the children of a group. `terminate-dependents` Only the dependents will be terminated. For example: If something happens to `group1`, then tomcat and php will get terminated. However, if any other cartridge or group is found in the parent group that `group1` belongs to, then that cartridge or group will remain as it is in WSO2 Private PaaS. If something happens to `php`, nothing will get terminated as php does not have any dependancies.	No	N/A	String	terminate-dependent, terminate-all, terminate-none
scalingDependents	Scaling Dependents	√	√		Defines if there are any dependencies with regard to scaling. When dependent scaling is defined among members (cartridge or a group), and scaling (scaling up or down) is taking place for any of the members, all other dependent members will also scale in order to maintain the defined ratio. For more information, see Dependent Scaling.	No	N/A	scalingDependents array	group.group1, cartridge.tomcat