The dependency logic will kick in when the cluster or group changes its state, e.g goes from active to inactive. If a single VM goes down in a cluster and is restarted by the autoscaler how will it reconnect (I assume it will go through the LB) ?
If the dependency check kicks in (e.g terminate-dependents), all depending clusters / groups will be terminated and then restarted so they should update the corresponding information required for the meta data service. So I think it depends on setting the appropriate termination flags (terminate-all, terminate-dependents, etc …) From: Lakmal Warusawithana [mailto:[email protected]] Sent: Tuesday, November 04, 2014 10:02 AM To: [email protected] Subject: Re: Grouping - How to update when a dependent instance is respwaned First of all, is any case can it restarted? to me termination can happen but nit restart right? This is dependency scenario, IMO it should handle by application dependancy. (may be with termination order) On Tue, Nov 4, 2014 at 5:26 PM, Udara Liyanage <[email protected]<mailto:[email protected]>> wrote: Hi Reka, Isuru, In a simpler scneario where PHP depends on MySQL, PHP instance get the MySQL details(host, username, password) from the metadata service. If MySQL instance is restarted, IP of the MySQL instance is changed, but it is not reflected to PHP instance. PHP app will fails when it tries to connect to the MySQL database. A possible solution 1) Agent listen to the ClusterInactivatedEvent 2) When the event received, check the inactivate cluster is a dependency of the particular instance's cluster 3) If so, re fetch the details from the metadata service. Better suggestions are appreciated. -- Udara Liyanage Software Engineer WSO2, Inc.: http://wso2.com<http://wso2.com/> lean. enterprise. middleware web: http://udaraliyanage.wordpress.com phone: +94 71 443 6897 -- Lakmal Warusawithana Vice President, Apache Stratos Director - Cloud Architecture; WSO2 Inc. Mobile : +94714289692 Blog : http://lakmalsview.blogspot.com/
