Bug 247980 - RFE: (strong and weak) service dependencies
RFE: (strong and weak) service dependencies
Product: Red Hat Cluster Suite
Classification: Red Hat
Component: rgmanager (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Lon Hohberger
Cluster QE
: FutureFeature
Depends On: 250101
Blocks: 247772
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Reported: 2007-07-12 10:07 EDT by Nils Philippsen
Modified: 2009-04-16 16:22 EDT (History)
5 users (show)

See Also:
Fixed In Version: RHBA-2008-0791
Doc Type: Enhancement
Doc Text:
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Clone Of:
Last Closed: 2008-07-25 15:15:20 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description Nils Philippsen 2007-07-12 10:07:05 EDT
+++ This bug was initially created as a clone of Bug #247783 +++

For SAP server systems, to be able to describe in which order e.g. the
underlying database and the SAP application server are started, a way to define
dependencies between services in the Cluster Suite is needed.

One service should be able to depend on multiple other services, e.g. an SAP
application service needs the database as well as its so-called central instance

These dependencies should be definable as "strong" or "weak" (or whatever
terminology fits best here). If service A depends on service B, "strong" would
mean that A must be stopped if B fails and started again when B recovers. "Weak"
would mean that A must be started after B is started but can recover by itself
if B fails during operation. For example, an SAP application server needs a
running DB to start (otherwise it bails out with an error message) but can
recover by itself if the DB fails and gets restarted. In this case it would
rollback unsaved transactions, but the user sessions would be preserved. If the
application server would get restarted in the event of a DB failure, all user
sessions would be lost which is quite undesirable.

-- Additional comment from nphilipp@redhat.com on 2007-07-11 09:22 EST --
Created an attachment (id=158945)
Patch against RHCS4 to implement dependencies between services

The patch I mailed to you ages ago which should implement dependencies between
services as an OCF script. It implements a "needs_recovery" flag which if true
would define a "strong" dependency or if false a weak one. Mind that I haven't
tested it thoroughly at that time and don't know if it is applicable to the
current version.
Comment 1 Russell Doty 2007-08-06 14:46:28 EDT
Set flags to propose for RHEL 4.7.
Comment 2 Lon Hohberger 2008-04-15 11:07:05 EDT
Pushed to RHEL4 git branch
Comment 5 errata-xmlrpc 2008-07-25 15:15:20 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.


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