Great! Thanks for the clarification! The term "replicas" was bit confusing, that's why.
On Tue, Sep 23, 2014 at 1:26 PM, Nirmal Fernando <nirmal070...@gmail.com> wrote: > Hi Imesh, > > On Tue, Sep 23, 2014 at 12:00 PM, Imesh Gunaratne <im...@apache.org> > wrote: > >> Regarding health monitoring in containers, as discussed the best approach >> would be to use a well-known docker container monitoring tool such as >> cAdvisor coupled with a cartridge agent instance per controller node. >> > > Yes, using cAdvisor we can monitor the docker containers as brought out > earlier too. Also, there's Heapster > https://github.com/GoogleCloudPlatform/heapster which enables monitoring > containers of a Kubernetes cluster. > > >> Why do we use the term "replicas" for the Kubernetes control node >> instances? Are we looking at providing HA for controller nodes rather than >> treating them as a cluster of controller nodes. >> > > Could you please explain what you meant by 'Kubernetes control node > instances' ? Here what replicas imply is the number of pods generated from > a pod template (so for a php cluster case, you will have a cluster of PHP > pods (in this case only 1 container resides inside the pod) distributed > across the Kubernetes cluster (a set of Kubernetes slaves)). > >> >> On Tue, Sep 16, 2014 at 7:04 AM, Nirmal Fernando <nirmal070...@gmail.com> >> wrote: >> >>> AFAIS Autoscaler's task is very simple in the container case. It just >>> need to create a kubernetes replication controller with the minimum number >>> of replicas initially via CC and need to update the number of replicas of >>> the same kubernetes replication controller (again via CC) based on the >>> health stats and make sure that the number of replicas are maintained under >>> maximum replicas count. >>> >>> >>> On Tue, Sep 16, 2014 at 3:20 PM, Lahiru Sandaruwan <lahi...@wso2.com> >>> wrote: >>> >>>> >>>> >>>> On Tue, Sep 16, 2014 at 2:57 PM, Lakmal Warusawithana <lak...@wso2.com> >>>> wrote: >>>> >>>>> >>>>> >>>>> On Tue, Sep 16, 2014 at 1:53 PM, Lahiru Sandaruwan <lahi...@wso2.com> >>>>> wrote: >>>>> >>>>>> Hi Akila, >>>>>> >>>>>> >>>>>> >>>>>> On Tue, Sep 16, 2014 at 12:49 PM, Akila Ravihansa Perera < >>>>>> raviha...@wso2.com> wrote: >>>>>> >>>>>>> Hi Raj, >>>>>>> >>>>>>> We can use the same CEP stream to publish cartridge agent health >>>>>>> stats. We can identify the instance type (container or VM type) by >>>>>>> retrieving member properties from the topology. But I don't think we >>>>>>> should >>>>>>> be doing that. >>>>>>> >>>>>>> IMO, we should not publish cartridge agent health stats from each >>>>>>> and every container. It's better if we can have a global agent per >>>>>>> Kubernetes host instance to monitor the health of every container and >>>>>>> also >>>>>>> in host instance itself. We can use a container monitoring agent like >>>>>>> cAdvisor to collect container health stats. >>>>>>> >>>>>> >>>>>> This is a good model. We will anyway have an agent in docker host as >>>>>> it is a multi-tenant cartridge instance. Then we can improve same agent >>>>>> to >>>>>> take-care of it's docker instances. We might need to let it know that it >>>>>> is >>>>>> running in a docker host. >>>>>> >>>>>> Do you suggest we completely get rid of agent inside dockers? >>>>>> >>>>>> Thanks. >>>>>> >>>>>>> >>>>>>> +1 for having a separate CEP execution plan for handling Docker >>>>>>> containers scenario. >>>>>>> >>>>>>> As for the ContainerClusterMonitor, we should clearly outline the >>>>>>> responsibilities of container monitor and VM monitor. Because since we >>>>>>> are >>>>>>> using Kubernetes for managing the life-cycle of containers, most of the >>>>>>> tasks are already taken care of. For eg - we don't need to start a new >>>>>>> container if an existing containers fails since Kubernetes will handle >>>>>>> that >>>>>>> failure. >>>>>>> >>>>>> >>>>>> My concern of letting Kubernetes control minimum values is, it is >>>>>> difficult to get the new member identified in Stratos side. Shall we take >>>>>> that control to Autoscaler as we do for VM clusters? >>>>>> >>>>> >>>>> Here Stratos will defining the min container count, but Kubernetes >>>>> will take care of up and running it. >>>>> >>>> >>>> Stratos might keep a higher value for active instances list for few >>>> minutes(until we get member fault for lost instance) in this case. It will >>>> affect Autoscaling decision and active instances shown in UIs. >>>> >>>> That was my initial concern. But if the Kubernetes is very fast on this >>>> HA action, it would be better to let Kubernetes handle it, as it would >>>> increase Stratos HA ability as well. >>>> >>>> Thanks. >>>> >>>> >>>>> >>>>> >>>>>> >>>>>> Thanks. >>>>>> >>>>>>> >>>>>>> WDYT? >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> -- >>>>>> Lahiru Sandaruwan >>>>>> Committer and PMC member, Apache Stratos, >>>>>> Senior Software Engineer, >>>>>> WSO2 Inc., http://wso2.com >>>>>> lean.enterprise.middleware >>>>>> >>>>>> email: lahi...@wso2.com cell: (+94) 773 325 954 >>>>>> blog: http://lahiruwrites.blogspot.com/ >>>>>> twitter: http://twitter.com/lahirus >>>>>> linked-in: http://lk.linkedin.com/pub/lahiru-sandaruwan/16/153/146 >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> Lakmal Warusawithana >>>>> Vice President, Apache Stratos >>>>> Director - Cloud Architecture; WSO2 Inc. >>>>> Mobile : +94714289692 >>>>> Blog : http://lakmalsview.blogspot.com/ >>>>> >>>>> >>>> >>>> >>>> -- >>>> -- >>>> Lahiru Sandaruwan >>>> Committer and PMC member, Apache Stratos, >>>> Senior Software Engineer, >>>> WSO2 Inc., http://wso2.com >>>> lean.enterprise.middleware >>>> >>>> email: lahi...@wso2.com cell: (+94) 773 325 954 >>>> blog: http://lahiruwrites.blogspot.com/ >>>> twitter: http://twitter.com/lahirus >>>> linked-in: http://lk.linkedin.com/pub/lahiru-sandaruwan/16/153/146 >>>> >>>> >>> >>> >>> -- >>> Best Regards, >>> Nirmal >>> >>> Nirmal Fernando. >>> PPMC Member & Committer of Apache Stratos, >>> Senior Software Engineer, WSO2 Inc. >>> >>> Blog: http://nirmalfdo.blogspot.com/ >>> >> >> >> >> -- >> Imesh Gunaratne >> >> Technical Lead, WSO2 >> Committer & PMC Member, Apache Stratos >> > > > > -- > Best Regards, > Nirmal > > Nirmal Fernando. > PPMC Member & Committer of Apache Stratos, > Senior Software Engineer, WSO2 Inc. > > Blog: http://nirmalfdo.blogspot.com/ > -- Imesh Gunaratne Technical Lead, WSO2 Committer & PMC Member, Apache Stratos
