* Re: [pcp] Suggestions for SGI ICE where we need to get quota information [not found] <51F90B6A.6050809@sgi.com> @ 2013-07-31 20:34 ` Nathan Scott 2013-08-01 15:11 ` Ben Myers 0 siblings, 1 reply; 2+ messages in thread From: Nathan Scott @ 2013-07-31 20:34 UTC (permalink / raw) To: Jeff Hanson, mikeh; +Cc: XFS, PCP Hi guys, ----- Original Message ----- > In SGI's ICE product we have a script that uses pcp to gather quota > information to feed to ganglia and to alert the admin if a project is > over quota. With newer pcp where pmcd is run as user pcp and not as > root we get failures to obtain the quota information. Changing back > to root or other similar techniques works (as expected). Since the > hosts that run this are cluster infrastructure nodes this may be the > hack we decide on but we'd like other suggestions. [ http://oss.sgi.com/bugzilla/show_bug.cgi?id=985 ] Hmm, interesting - sorry about that, its unintended fallout and it did not occur to me that the XFS quota metrics would be affected. I would strongly recommend not going back to running pmcd as root, kittens will surely die (although it is likely to be your only solution currently). There is a better way we can tackle this - we should isolate those parts that need to run as root, and run them that way. This means we need to transition these quota metrics into a new PMDA which runs as root, separately to pmcd. In a quirky twist, I happened to come across a very similar problem recently with the xfs.control.reset metric - this needs root access too in order to function (it provides a reset-stats-back-to-zero mechanism by writing to a procfs file), so it also was an unintended victim of the unprivileged-pmcd changes. Thus, I propose we abstract out the xfs.* and quota.* (which, despite being generically named "quota" metrics, are all XFS-specific) into a new pmdaxfs which we run as root, in exactly the same way pmdaproc is now run as root. We will need to manage the PMID transition (domain number on these metrics will change) via pmlogrewrite, but that is a well-trod path now and happily pmdaproc is an existence-proof that we can successfully make these transitions. If we do it correctly, we should be able to do this transparently so that nobody notices. However, Murphy being Murphy ... I've CC'd the XFS list to let 'em know this is coming. cheers. -- Nathan _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [pcp] Suggestions for SGI ICE where we need to get quota information 2013-07-31 20:34 ` [pcp] Suggestions for SGI ICE where we need to get quota information Nathan Scott @ 2013-08-01 15:11 ` Ben Myers 0 siblings, 0 replies; 2+ messages in thread From: Ben Myers @ 2013-08-01 15:11 UTC (permalink / raw) To: Nathan Scott; +Cc: Jeff Hanson, PCP, mikeh, XFS On Wed, Jul 31, 2013 at 04:34:16PM -0400, Nathan Scott wrote: > ----- Original Message ----- > > In SGI's ICE product we have a script that uses pcp to gather quota > > information to feed to ganglia and to alert the admin if a project is > > over quota. With newer pcp where pmcd is run as user pcp and not as > > root we get failures to obtain the quota information. Changing back > > to root or other similar techniques works (as expected). Since the > > hosts that run this are cluster infrastructure nodes this may be the > > hack we decide on but we'd like other suggestions. > > [ http://oss.sgi.com/bugzilla/show_bug.cgi?id=985 ] > > Hmm, interesting - sorry about that, its unintended fallout and it did > not occur to me that the XFS quota metrics would be affected. I would > strongly recommend not going back to running pmcd as root, kittens will > surely die (although it is likely to be your only solution currently). > > There is a better way we can tackle this - we should isolate those > parts that need to run as root, and run them that way. This means we > need to transition these quota metrics into a new PMDA which runs as > root, separately to pmcd. > > In a quirky twist, I happened to come across a very similar problem > recently with the xfs.control.reset metric - this needs root access > too in order to function (it provides a reset-stats-back-to-zero > mechanism by writing to a procfs file), so it also was an unintended > victim of the unprivileged-pmcd changes. > > Thus, I propose we abstract out the xfs.* and quota.* (which, despite > being generically named "quota" metrics, are all XFS-specific) into a > new pmdaxfs which we run as root, in exactly the same way pmdaproc is > now run as root. We will need to manage the PMID transition (domain > number on these metrics will change) via pmlogrewrite, but that is a > well-trod path now and happily pmdaproc is an existence-proof that we > can successfully make these transitions. > > If we do it correctly, we should be able to do this transparently so > that nobody notices. However, Murphy being Murphy ... I've CC'd the > XFS list to let 'em know this is coming. Thanks Nathan, we'll keep an eye out. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs ^ permalink raw reply [flat|nested] 2+ messages in thread
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