I browsed over the previously exchanged emails, compiled and summarized it
below (please correct me when my understanding is incorrect).
+ service Groups definitions are deployed independently of each other (similar
to deploying a cartridge or policy)
(something along the lines like “deploy-service-group service-group-
definition.json”, for sample definition see [1], [2])
+ service Groups are named and can be referenced in a composite application
+ generally, service groups logically groups other service group definitions
and cartridge types and describes their interdependencies
+ dependencies are described as part of the service group definition
+ For the format and examples of a service group see [1], [2] below
+ other characteristics of service groups like auto-scaling, deployment
restrictions are describes as part of the composite application
+ Composite application is deployed independent of service groups
+ composite application references (already deployed) service groups and
cartridges
+ provides required subscription and deployment information for service group
definitions and cartridge types
+ creates a specific instance of a service group / cartridge type by defining a
service group alias and cartridge alias and also by assigning characteristics
like auto-scaling, deployment policy, etc … which are specific for the
application (for instance another application could define other deployment
policies for the same service group definition)
+ composite application format and example see [3]
+ N number of applications will be supported ?
{
"name": "group1",
"cartridges": [
"mysql", "mongoDB"
],
"dependencies": {
"killBehaviour": "kill-none"
}
}
[2].
{
"name": "group2",
"subGroups": [
"group1"
],
"cartridges": [
"php"
],
"dependencies": {
"startupOrder": [
{
"start": "group.group1",
"after": "cartridge.php"
}
],
"killBehaviour": "kill-dependents"
}
}
[3]
{
"applicationId": "test_app",
"alias": "myapp1",
"components": [
{
"group": "group1",
"alias": "mygroup1",
"deploymentPolicy": "dep_policy_group1",
"autoscalingPolicy": "autoscale_policy_group1",
"subscribables": [
{
"type": "mysql",
"alias": "mygroup1.mysql",
"deploymentPolicy": "dep_policy_mysql",
"autoscalingPolicy": "autoscale_policy_mysql"
},
{
"type": "php",
"alias": "mygroup1.php",
"deploymentPolicy": "dep_policy_php",
"autoscalingPolicy": "autoscale_policy_php",
"repoURL": "www.mygit.com/php.git",
"privateRepo": "true",
"repoUsername": "admin",
"repoPassword": "xxxx"
}
]
},
],
"cartridges": [
{
"type": "tomcat",
"alias": "mytomcat",
"deploymentPolicy": "dep_policy_tomcat",
"autoscalingPolicy": "autoscale_policy_tomcat",
"repoURL": "www.mygit.com/tomcat.git",
"privateRepo": "false",
"repoUsername": "admin",
"repoPassword": "yyyy"
}
]
}
From: Shaheedur Haque (shahhaqu)
Sent: Tuesday, July 08, 2014 3:16 AM
To: dev@stratos.apache.org; Martin Eppel (meppel)
Subject: RE: Composite Application Definition with Reference to Deployed
Service Groups
Hi Isuru,
See below…
From: isu...@wso2.com<mailto:isu...@wso2.com> [mailto:isu...@wso2.com] On
Behalf Of Isuru Haththotuwa
Sent: 04 July 2014 09:11
To: dev; Martin Eppel (meppel)
Subject: Composite Application Definition with Reference to Deployed Service
Groups
Hi all,
Since we have the Service Group persistence now, we can change the Composite
Application to refer the previously deployed Service Groups [1]. WDYT?
[srh] I think I missed groups being deployed/persisted separately. Does the
“subscription” information (meaning deployment and autoscaling only for a
group, everything for a cartridge), get persisted with each group?
The Subscribable section will carry subscription level information related to
each cartridge in the group. Even for a nested group, we can specify this
information as a flat structure (an array) since we already have captured
dependency information from the deployed Service Groups. I believe this will
reduce the complexity of this JSON definition. Note that there are policies
(autoscaling/deployment) defined per group and per Subscribable. This is for
the purpose of member/group wise scaling. Also note the alias I have used for
two Subscribables in the group; I believe we can derive that from the group
alias without the user having to give an explicit alias for each Subscribable.
Sent a separate mail to the dev list suggesting that earlier with subject [2].
[srh] Some questions:
1. I think I don’t understand what application.components is, I imagined
it rather as application.groups? That way, the application is itself just a
subclass of group, albeit the one at the top and carrying any specialisation
that implies.
2. In [1] you don’t show nested groups. How should those be represented?
Or are they not needed because groups are being deployed/persisted separately,
and this application only specifies the top level groups/cartridges and their
respective “subscriptions”?
I’m a little uneasy about the inline model of the “subscription” information. I
tend to think that this can be factored out (though it is not the end of the
world to keep it inline) subject to my understanding of questions 1 and 2.
BTW, I saw this email after I responded to [2] ☺
Thanks, Shaheed
[1].
{
"applicationId": "test_app",
"alias": "myapp1",
"components": [
{
"group": "group1",
"alias": "mygroup1",
"deploymentPolicy": "dep_policy_group1",
"autoscalingPolicy": "autoscale_policy_group1",
"subscribables": [
{
"type": "mysql",
"alias": "mygroup1.mysql",
"deploymentPolicy": "dep_policy_mysql",
"autoscalingPolicy": "autoscale_policy_mysql"
},
{
"type": "php",
"alias": "mygroup1.php",
"deploymentPolicy": "dep_policy_php",
"autoscalingPolicy": "autoscale_policy_php",
"repoURL": "www.mygit.com/php.git<http://www.mygit.com/php.git>",
"privateRepo": "true",
"repoUsername": "admin",
"repoPassword": "xxxx"
}
]
},
],
"cartridges": [
{
"type": "tomcat",
"alias": "mytomcat",
"deploymentPolicy": "dep_policy_tomcat",
"autoscalingPolicy": "autoscale_policy_tomcat",
"repoURL": "www.mygit.com/tomcat.git<http://www.mygit.com/tomcat.git>",
"privateRepo": "false",
"repoUsername": "admin",
"repoPassword": "yyyy"
}
]
}
[2]. Composite Application Deployment and Subscription - Single Alias for a
Group
--
Thanks and Regards,
Isuru H.
+94 716 358 048
