I think this might not cover the use cases and we still need to support
dependencies of same type cartridges in service groups. I wonder if we can
extend the dependency description model and add an extra parameter which
allows us to refer to instance of same type cartridges:
{
"name": "group5",
"subGroups": [
],
"cartridges": [
"c1.1", "c1.2", "c3", “c4”
],
"dependencies": {
"startupOrders": [
"cartridge.c3,cartridge.c1.1”,
"cartridge.c4,cartridge.c1.2”,
],
"terminationBehaviour": "terminate-dependents"
}
}
with cartridge cartridge.c1.1 and cartridge.c1.2 using different subscription
parameters (like deployment policy, etc ).
In this configuration, c3 and c4 will start up in parallel and an instance of
c1 cartridge will start up once c3 is active and respectively when c4 becomes
active.
WDYT ?
Thanks
Martin
From: [email protected] [mailto:[email protected]] On Behalf Of Isuru Haththotuwa
Sent: Wednesday, November 19, 2014 9:15 PM
To: dev
Subject: Re: [grouping][question] cartrdige type in dependency definition
Hi Martin,
In a Service Group, we do not have runtime data, as aliases and other relevant
subscription data are provided in the application deployment.
If you need to start two instances of the same cartridge type, what you can do
is to put them in the application itself without using a group, and then
specify the startup order using cartridge aliases:
"startupOrders": [
"cartridge.<alias1>, cartridge.<alias2>, cartridge.<alias3>"
],
all the aliases refer to the same cartridge type.
On Thu, Nov 20, 2014 at 9:35 AM, Martin Eppel (meppel)
<[email protected]<mailto:[email protected]>> wrote:
Hi Udara,
Yes, I confirmed, there are real use cases where we have dependencies on the
same cartridge type but different subscriptions, one is an example of active /
standby scenario another one a scenario to patch / upgrade the system.
Quoting the response below:
ns-01 and ns-02 are instances of a network server cluster. Strictly speaking
they belong to the same cluster so having both be the same cartridge type makes
sense. Making them different cartridge types seems wrong. We really only need
either ns-01 or ns-02 to be up in order to declare the cluster as available and
I can't see how we do that if we use different cartridge types.
One of the original use cases was to use grouping to represent a cluster. One
use cases might involve have multiple subscriptions representing collectively a
cluster, so each having the same cartridge type would be useful. Each
subscription in this case would have one or more instances. For example, if
we want to represent a cluster with a subscription a. At some point later, we
might want to add a subscription b to the group which point to a different
version of code (likely a patched version) and remove subscription a after
we've deploy and verified subscription b. I imagine doing this by revising a
group with additional subscriptions with the same cartridge type.
I believe Matt has a similar requirement where one VM is in active state and
the other is in standby.
From: Martin Eppel (meppel)
Sent: Wednesday, November 19, 2014 6:21 PM
To: [email protected]<mailto:[email protected]>
Subject: RE: [grouping][question] cartrdige type in dependency definition
Hi Udara,
No problem, I was just wondering if it is supported or not.
On the other hand we might have a real use case, let me follow up on this
Thanks
Martin
From: Udara Liyanage [mailto:[email protected]]
Sent: Wednesday, November 19, 2014 6:16 PM
To: dev
Subject: Re: [grouping][question] cartrdige type in dependency definition
Hi Martin,
Creating another cartridge type is just changing the type parameter of the
existing cartridge json if you are using the base image approach and deploying
the new json.
If the requirement is only the easiness in testing, I don't think implementing
this feasibility is necessary given that we are in a tight schedule. However if
there is a real world use case I am OK.
Touched, not typed. Erroneous words are a feature, not a typo.
--
Thanks and Regards,
Isuru H.
+94 716 358 048
