Hi Ralph, thank you for your quick answer. That Knowledge base article indeed presents that dependencies possibility. Unfortunately I do not have the required version of rgmanager :( kind regards, Laszlo On 07/28/2011 10:34 AM, Ralph.Grothe@xxxxxxxxxxxxxx wrote: > > >> -----Original Message----- >> From: linux-cluster-bounces@xxxxxxxxxx >> [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of Budai > Laszlo >> Sent: Thursday, July 28, 2011 9:06 AM >> To: linux-cluster@xxxxxxxxxx >> Subject: Re: service startup order >> >> @Ralph: could you please provide me some references where >> have you found >> those attributes of the service tag (depend, depend_mode) and >> for the RM >> tag (central_processing)? Thank you. > Even Digimer is metioning this attribute in her excellent wiki > > http://wiki.alteeve.com/index.php/RHCS_v2_cluster.conf#central_pr > ocessing > > > If you have a login account at RHN you may find this article in > their knowledge base > > https://access.redhat.com/kb/docs/DOC-26981 > > > Apart from that the only text where this attrib was used that I > have come across so far was an RH doc treating deployment of SAP > on RHCS > But it only appears there in a sample config snippet without > further explanation. > I guess that they needed to activate it because they were using > the RHCS event processing interface? > > http://www.redhat.com/f/pdf/ha-sap-v1-6-4.pdf > >> Kind regards, >> Laszlo >> >> >> On 07/28/2011 09:24 AM, Ralph.Grothe@xxxxxxxxxxxxxx wrote: >>> Hi Digimer, hi Lazlo, >>> >>> sorry, for intruding your thread but this is something that I > am >>> also interested in and which I haven't fully fathomed yet. >>> >>>> -----Original Message----- >>>> From: linux-cluster-bounces@xxxxxxxxxx >>>> [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of > Digimer >>>> Sent: Thursday, July 28, 2011 2:51 AM >>>> To: linux clustering >>>> Subject: Re: service startup order >>>> >>>> Parallel services will be started simultaneously. Services >>>> configured as >>>> service trees will start in the order that they are defined >>>> (and stopped >>>> in reverse order). >>>> >>>> This covers the start order well: >>>> - https://fedorahosted.org/cluster/wiki/ResourceTrees >>>> >>> The referred to wiki article only seems to treat >>> starting/stopping order and hierarchy (parent-child vs. > sibling) >>> of resources within one service aka resource group. >>> That sounds pretty clear. >>> But what about ordering and possible dependencies between >>> separate services? >>> >>> You mentioned service trees. You didn't actually mean > resource >>> trees? >>> If however your wording was deliberate (what I assume) I > wonder >>> if one can nest service tag blocks as one can nest resource > tags >>> within a single service block to express dependencies or >>> hierarchy and hence starting order between and of services? >>> Because all the sample configuration snippets I have seen so > far >>> in various docs lack such nesting of services. >>> >>> The reason that interests me is because I have such a case > where >>> a customer requires such a dependency between two distinct >>> services that during normal operation (i.e. no node has left > the >>> cluster) are hosted on different nodes. >>> I told them, from what I have perceived of HA clustering and > RHCS >>> in particular so far, that if they wish to express such an >>> interdependency that they would have to put all resources > which >>> are now split up in two services, in a nested manner that > would >>> map the intended hierarchy, in a single service. >>> >>> Because they insisted on their layout I searched a little and >>> discovered the, in the official RHCS Admin doc not mentioned, >>> service tag attributes "depend" and "depend_mode". >>> >>> However, their usage at first seemed pretty useless because > the >>> clusterware seemed to completely ignore them and start/stop >>> services in sometimes unpredictable ways and even restarted > them >>> at random. >>> Until I, more by accident, discovered that additionally the > "rm" >>> tag's attribute "central_processing" needed to be defined and >>> assigned to "1" or "true" for this feature to work > approximately. >>> I say apprimately here because we still have issues with this >>> cluster that require futher testing. >>> I hardly dare mentioning, that unfortunately this system > already >>> went into production, now of course lacking any HA, >>> why we had to defer further testing. >>> >>> >>> Regards >>> Ralph >>> >>> >>> >>> -- >>> Linux-cluster mailing list >>> Linux-cluster@xxxxxxxxxx >>> https://www.redhat.com/mailman/listinfo/linux-cluster >>> >> -- >> Linux-cluster mailing list >> Linux-cluster@xxxxxxxxxx >> https://www.redhat.com/mailman/listinfo/linux-cluster >> > -- > Linux-cluster mailing list > Linux-cluster@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-cluster > -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
