Yes exactly, the application provider needs to decide how to handle this behaviour: 1. Either use termination behaviour 2. Or update metadata service accordingly on member termination & activation events
On Wed, Nov 5, 2014 at 11:16 AM, Gayan Gunarathne <[email protected]> wrote: > Hi Udara, > > On Wed, Nov 5, 2014 at 10:37 AM, Udara Liyanage <[email protected]> wrote: > >> Hi Imesh, >> >> When new MySQL started, it publish its details to the metadata which will >> overwrite the existing values. >> > When instance is restarted why we are overwrite the existing values? For > me it is same as terminate the service and start the new instance. In that > case I think we can remove the existing data and create new set of meta > data for new instance. I think it will simplify the meta data service > behavior. WDYT? > >> >> In terminate-all, terminate-dependent this won't be an issue since PHP >> instance also get killed. So the idea I got is, it is the responsibility of >> the application deployer to mark it terminate-dependent in such a case. >> > +1 for this > >> >> On Wed, Nov 5, 2014 at 12:01 AM, Imesh Gunaratne <[email protected]> >> wrote: >> >>> On Tue, Nov 4, 2014 at 11:43 PM, Udara Liyanage <[email protected]> wrote: >>> >>>> Hi Lakmal, >>>> >>>> What I meant by restarted is starting another instance when an existing >>>> instance is terminated for some reason. Application monitor respin another >>>> instance when a dependency is terminated. However the data fetched from >>>> metadata service (by PHP instance) is outdated. >>>> >>>> As I can recall we discussed this issue before, the meta-data service >>> can keep the member id against each record and invalidate the record if the >>> member is terminated. Then the next member comes in can add a new record. >>> >>>> @Imesh there might be cases where LB is not included in an application. >>>> In PHP and MySQL scenario it may be better to go via LB, but in generic it >>>> is ok to go without an LB >>>> >>> Agree, there can be situations where we only need one instance of a >>> service. >>> >>> >>> -- >>> Imesh Gunaratne >>> >>> Technical Lead, WSO2 >>> Committer & PMC Member, Apache Stratos >>> >> >> >> >> -- >> >> Udara Liyanage >> Software Engineer >> WSO2, Inc.: http://wso2.com >> lean. enterprise. middleware >> >> web: http://udaraliyanage.wordpress.com >> phone: +94 71 443 6897 >> > > > > -- > > Gayan Gunarathne > Technical Lead > WSO2 Inc. (http://wso2.com) > email : [email protected] | mobile : +94 766819985 > > -- Imesh Gunaratne Technical Lead, WSO2 Committer & PMC Member, Apache Stratos
