nfs mount locally exported directories in a Red HAt Cluster (v3)?

[Rick Stevens]

evdhn at advalvas.be wrote:
>>evdhn at advalvas.be wrote:
>>
>>>>>>>In a Red Hat HA Cluster (v3), how can you nfs mount a directory
>>>>>>>exported
>>>>>>>by a cluster service that is currently local to the cluster member?
>>>>>>>I keep getting permission denied errors.  It works fine when I move
>>>>>>>the
>>>>>>>cluster service to the other cluster member.  The firewall has been
>>>>>>>stoppped, just to make sure it wasn't part of the problem.
>>>>>>
>>>>>>Make sure you have portmapper and nfslock running on both the client
>>>>>>and
>>>>>>server.  That's the most common problem.
>>>>>>----------------------------------------------------------------------
>>>>>>- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
>>>>>>----------------------------------------------------------------------
>>>>>
>>>>>Thanks for your answer Rick, but apparently I explained poorly.
>>>>>
>>>>>This is a two-member cluster with hostnames arneb and nihal and
>>>>>services
>>>>>lepusbb and lepustl.
>>>>>When service lepusbb runs on arneb, I cannot nfs mount its device on
>>>>>arneb
>>>>>using the service name.  I.e.
>>>>># mount -t nfs lepusbb:/usr/local/lepus-bb /usr/local/bb
>>>>>does not work on arneb, but it does work on nihal.
>>>>>Similarly, I can mount lepustl:/usr/local/lepus-tl on arneb but not on
>>>>>nihal.
>>>>>
>>>>>I meanwhile found that
>>>>># mount -t nfs arneb:/usr/local/lepus-bb /usr/local/bb
>>>>>does work, so I'm currently using that as a workaround, but obviously,
>>>>>when a failover would occur while the devices are locally mounted, my
>>>>>scripts wil be in trouble.
>>>>>
>>>>>And yes, portmapper and nfslock are running:
>>>>># ps auxw | egrep -e lock -e portm | grep -v grep
>>>>>rpc       3109  0.0  0.0  1672  608 ?        S    10:36   0:00 portmap
>>>>>root      3314  0.0  0.0     0    0 ?        SW   10:36   0:00 [lockd]
>>>>>root      3453  0.0  0.0  3064 3064 ?        S<L  10:36   0:00
>>>>>/usr/sbin/clulockd
>>>>
>>>>First, are you sure the device is being exported by arneb and that arneb
>>>>is permitted to mount it?  A "showmount -e arneb" will show what's being
>>>>exported and who's allowed to look at it.
>>>>
>>>>I'm not familiar with RH's HA (high availability) structure so I can't
>>>>speak to the details, but generally it's something along those lines.
>>>>----------------------------------------------------------------------
>>>>- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
>>>>----------------------------------------------------------------------
>>>
>>>
>>>It must be a RH HA thing then.
>>>
>>># showmount -e arneb
>>>Export list for arneb:
>>>/usr/local/lepus-bb                          arneb,nihal
>>>/usr/local/lepus-bb/server                   gienah,albireo,sair,ruchba
>>>/usr/local/lepus-bb/content                  gienah,albireo,sair,ruchba
>>>/usr/local/lepus-bb/sessions                 gienah,albireo,sair,ruchba
>>>/usr/local/lepus-bb/course_image_main_images gienah,albireo,sair,ruchba
>>>
>>>Even when I specify that all nodes ("*") should have access, it still
>>>won't work. :-(
>>
>>I'm not certain what HA means by "service", but generally, NFS mounts
>>specify the remote end as "nodename:/export", not as "service:/export".
>>Try:
>>
>>	mount -t nfs arneb:/usr/local/lepus-bb /usr/local/bb
>>
>>on nihal and see if that works.  It should.  Also make sure that the
>>server (arneb) is running nfsd.  The existance of an exports file should
>>trigger it.
> A service (= linux, Tru64 terminology, = resource group on aix, = packages
> on HP UNIX if I remember correctly) roughly is a collection of a virtual
> ip-address (alias), disk devices, and application processes, that can be
> accessed through the virtual ip-address.
> In my current situation, arneb and nihal are hostnames, lepusbb is an
> alias (normally on eth0:1 when the service runs on arneb).

Do the aliases resolve either through DNS or via /etc/hosts?  Remember
that DNS has no concept of "service".  It knows hosts and exports (as
shown by the "showmount -e" command).  On nihal, try both of these
commands

	showmount -e lepusbb
	showmount -e arneb

See if the lists they show are different based on the two aliases.

> RH HA is explained in:
> http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/pdf/rh-cs-en.pdf
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
- Real Time, adj.: Here and now, as opposed to fake time, which only -
-                        occurs there and then                       -
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