> -----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
