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From Lahiru Sandaruwan <lahi...@wso2.com>
Subject Re: [Discuss] Cartridge definition doesn't need "maxInstanceLimit" property anymore
Date Tue, 17 Mar 2015 03:43:21 GMT
Hi Shaheed,

We can define the maximum number of instances that can be spawned per
partition in deployment policy. You can find a simple sample which is
written for next developer preview at [1]. This sample is an end to end
sample with single cartridge application and Mock IaaS. See the step 5
for *partitionMax
*usage.

Thanks.

[1]
https://cwiki.apache.org/confluence/display/STRATOS/4.1.0-Beta+Install+Stratos+with+a+Mock+IaaS

On Mon, Mar 16, 2015 at 5:24 PM, Shaheedur Haque (shahhaqu) <
shahhaqu@cisco.com> wrote:

>  Hi Lahiru,
>
>
>
> What do you mean by partition max? Where is it specified?
>
>
>
> Thanks, Shaheed
>
>
>
> *From:* Lahiru Sandaruwan [mailto:lahirus@wso2.com]
> *Sent:* Saturday, March 14, 2015 2:31 AM
>
> *To:* dev
> *Subject:* Re: [Discuss] Cartridge definition doesn't need
> "maxInstanceLimit" property anymore
>
>
>
> Hi Shaheedur,
>
>
>
> This is the same model we had from 4.0.0 and we did not change the concept
> in this release. Explanation as below,
>
>
>
> There can be several partitions that a particular cartridge(service
> cluster) can span over.
>
>
>
> E.g.
>
>
>
> Say PHP cartridge have 3 partitions(P1 and P2). P1 has 3 as partition max
> and P1 has 6 as partition max.
>
> PHP has 2 as Cartridge min and 5 as Cartridge max.
>
>
>
> *With one-after-another algorithm between partitions,*
>
>
>
> *Min instances creation,*
>
> Both the minimum instances will be created in P1.
>
>
>
> *Scaling up,*
>
> First scaling up member will be created in P1 and the next members will be
> created in P2. It can only create 3 members in P1 and 2 members in P2 as it
> will reach it's max of 5 members. That's where the cartridge max is used.
>
>
>
>
> * With round-robin algorithm between partitions,*
>
>
>
> *Min instances creation,*
>
> One of the minimum instances will be created in P1 and the other in P2.
>
>
>
> *Scaling up,*
>
> Scaling up members will be created in round-robin manner in P1 and P2.
>
>
>
> On Fri, Mar 13, 2015 at 9:31 PM, Shaheedur Haque (shahhaqu) <
> shahhaqu@cisco.com> wrote:
>
>  After discussing a bit with Imesh, we identified 3 points that need
> clarifying:
>
>
>
> ·        If there is to be a cartridgeMin attribute, it should at least
> be optional and take its default value from the deployment policy minimum
> value.
>
>  Do you mean the minimum value per partition? I cannot see such value.
> There is only maximum in partitions of deployment policy.
>
>  ·        If there is to be a cartridgeMin attribute, its behaviour needs
> to be specified with respect to the deployment min and max. For example,
> what happens if the cartridgeMin is greater than the deployment max?
>
>
>
> This is a good question. Ideally, with current implementation,  it will
> not create instances beyond partition Max.
>
>  ·        We need to find out what, if anything, the cartridgeMax is for.
>
>
>
> IMO partition max are for limiting the instances in IaaS, for particular
> region, zone or so. But cartridge need it's own limit when it scales up,
> where reusable partitions may have less or more space. Therefore we need
> both.
>
>
>
> *Stratos will create instances until the lowest of those max
> values(Cartridge max and partition max).*
>
>
>
> Thanks.
>
>
>
>
>
>
>
> *From:* Shaheedur Haque (shahhaqu)
> *Sent:* 13 March 2015 08:22
> *To:* dev@stratos.apache.org
> *Subject:* RE: [Discuss] Cartridge definition doesn't need
> "maxInstanceLimit" property anymore
>
>
>
> Hi Reka,
>
>
>
> First, I strongly suggest we not use internal terms like “cluster”, since
> they are not part of the user visible model, to explain user visible
> behaviour. For example, my understanding of a cluster is almost certainly
> not as good as you think it is J. Nevertheless…
>
>
>
> I think I understand: you are saying that when a group scales up, you will
> initially spin up cartridgeMin instances, correct? If this is not correct,
> please clarify. If it is correct, then:
>
>
>
> ·        I would have thought that the correct behaviour was to enforce
> the minimum value specified in the deployment policy.
>
> ·        Even if there is a theoretical use case where a new group should
> start with a different values that the one in the deployment policy, you
> would need to clearly explain how cartridgeMin relates to both deployment
> min **and** max when the values clash. I say we should rather keep it
> simple and use the deployment policy values.
>
> ·        What is cartridgeMax used for?
>
>
>
> Thanks, Shaheed
>
>
>
> *From:* Reka Thirunavukkarasu [mailto:reka@wso2.com <reka@wso2.com>]
> *Sent:* 13 March 2015 02:54
> *To:* dev
> *Subject:* Re: [Discuss] Cartridge definition doesn't need
> "maxInstanceLimit" property anymore
>
>
>
> Hi Shaheedur,
>
> Sorry for the confusion..Let me explain what cartridgeMin is and the
> purpose of having it in the application. As you already aware, we have
> the group instances/cluster instances concept with 4.1.0 in order to
> support group scaling. For the cluster level, we will need a minimum count
> for the members in order to maintain this minimum count all the time. Since
> we have cluster instance concept, we will need a minimum members per
> cluster instance level. So that whenever a new cluster instance is getting
> created, we can satisfy the cluster instance by creating the cartridgeMin
> number of members and can send the clusterInstanceActivated event. That's
> why
> cartridgeMin got introduced in the application. "cartridgeMin" means the
> minimum number of members per cluster instance.
>
> When a cluster instance is getting created, let's say you have two as the
> cartridgeMin. In that case in order to create those two members, we will
> need to find out the partition. For that, we will get the associated policy
> and find the suitable partition to spin those members one by one. If one of
> the partition is full, our algorithm is capable of choosing the next
> available partition.
>
> Please let me know, if it is unclear still..
>
> Thanks,
>
> Reka
>
>
>
> On Thu, Mar 12, 2015 at 11:31 AM, Shaheedur Haque (shahhaqu) <
> shahhaqu@cisco.com> wrote:
>
> I’m now thoroughly confused as to what is going and staying. I **think**
> the latest part of this thread says we need to keep cartridgeMin and
> cartridgeMax. Why do we need cartridgeMin and cartridgeMax at this point in
> the system?
>
>
>
> *From:* Reka Thirunavukkarasu [mailto:reka@wso2.com]
> *Sent:* 12 March 2015 17:09
> *To:* dev
> *Subject:* Re: [Discuss] Cartridge definition doesn't need
> "maxInstanceLimit" property anymore
>
>
>
> Hi Raj,
>
>
>
> On Thu, Mar 12, 2015 at 10:01 AM, Rajkumar Rajaratnam <rajkumarr@wso2.com>
> wrote:
>
>
>
>
>
> On Thu, Mar 12, 2015 at 10:24 PM, Reka Thirunavukkarasu <reka@wso2.com>
> wrote:
>
> Hi Lahiru/Raj,
>
> I think that we have introduced this *cartridgeMin/cartridgeMax *when
> introducing the deployment policy for cartridge and groups as global
> deployment policy. Since we have the same concept now, i would like to
> review the implementation and confirm whether it is required or not. Can
> you please hold until that? I will quickly confirm on this..
>
>
>
> Hi Reka, I am not sure whether I understood you wrong. Yes we need
> cartridgeMin and cartridgeMax, which are defined in application json. But
> we don't need *maxInstanceLimit* property, which used to define in
> cartridge json in 4.0.0. I guess we have already removed references to this
> property from code base, but not from sample artifacts.
>
>
>
> Thanks for the details.. We no longer using *maxInstanceLimit. *+1 to
> remove it..I was bit confused when i read the mail body as i thought that
> you are going to remove cartidgeMin/cartridgeMax. Now it is clear..
>
> Thanks,
>
> Reka
>
>
>
>
>
> Thanks,
>
> Reka
>
>
>
> On Thu, Mar 12, 2015 at 9:40 AM, Lahiru Sandaruwan <lahirus@wso2.com>
> wrote:
>
> Noticed today. It was misleading as we have this left in samples. I will
> clean this up.
>
>
>
> Thanks.
>
>
>
> On Thu, Mar 12, 2015 at 10:04 PM, Rajkumar Rajaratnam <rajkumarr@wso2.com>
> wrote:
>
> Hi Devs,
>
> We are defining cartridge min max count in application definition.
>
> {
>     "applicationId": "single-cartridge-app",
>     "alias": "single-cartridge-app",
>     "multiTenant": false,
>     "components": {
>         "cartridges": [
>             {
>                 "type": "php",
>
> *"cartridgeMin": 1,                 "cartridgeMax": 10,*
>                 "subscribableInfo": {
>                     "alias": "my-php",
>                     "autoscalingPolicy": "autoscaling-policy-1",
>                     "deploymentPolicy": "deployment-policy-1",
>                     "artifactRepository": {
>                         "privateRepo": false,
>                         "repoUrl": "
> https://github.com/imesh/stratos-php-applications.git",
>                         "repoUsername": "",
>                         "repoPassword": ""
>                     }
>                 }
>             }
>         ]
>     }
> }
>
> In 4.0.0, we used to define these in cartridge definition, in IaaS
> provider section. We have now removed it from cartridge bean classes.
> However I can see that samples still have this attribute. I will remove it.
>
> Thanks.
>
>
> --
>
> Rajkumar Rajaratnam
>
> Committer & PMC Member, Apache Stratos
>
> Software Engineer, WSO2
>
> Mobile : +94777568639
>
> Blog : rajkumarr.com
>
>
>
>
>
> --
>
> --
> Lahiru Sandaruwan
>
> Committer and PMC member, Apache Stratos,
> Senior Software Engineer,
> WSO2 Inc., http://wso2.com
>
> lean.enterprise.middleware
>
> phone: +94773325954
> email: lahirus@wso2.com blog: http://lahiruwrites.blogspot.com/
> linked-in: http://lk.linkedin.com/pub/lahiru-sandaruwan/16/153/146
>
>
>
>
>
>   --
>
> Reka Thirunavukkarasu
> Senior Software Engineer,
> WSO2, Inc.:http://wso2.com,
>
> Mobile: +94776442007
>
>
>
>
>
>
> --
>
> Rajkumar Rajaratnam
>
> Committer & PMC Member, Apache Stratos
>
> Software Engineer, WSO2
>
> Mobile : +94777568639
>
> Blog : rajkumarr.com
>
>
>
>
> --
>
> Reka Thirunavukkarasu
> Senior Software Engineer,
> WSO2, Inc.:http://wso2.com,
>
> Mobile: +94776442007
>
>
>
>
>
>
> --
>
> Reka Thirunavukkarasu
> Senior Software Engineer,
> WSO2, Inc.:http://wso2.com,
>
> Mobile: +94776442007
>
>
>
>
>
>
>
> --
>
> --
> Lahiru Sandaruwan
>
> Committer and PMC member, Apache Stratos,
> Senior Software Engineer,
> WSO2 Inc., http://wso2.com
>
> lean.enterprise.middleware
>
> phone: +94773325954
> email: lahirus@wso2.com blog: http://lahiruwrites.blogspot.com/
> linked-in: http://lk.linkedin.com/pub/lahiru-sandaruwan/16/153/146
>
>
>



-- 
--
Lahiru Sandaruwan
Committer and PMC member, Apache Stratos,
Senior Software Engineer,
WSO2 Inc., http://wso2.com
lean.enterprise.middleware

phone: +94773325954
email: lahirus@wso2.com blog: http://lahiruwrites.blogspot.com/
linked-in: http://lk.linkedin.com/pub/lahiru-sandaruwan/16/153/146

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