Bug 1567511

Summary: [manila] Disable NFS-Ganesha caching when using cephfs-nfs driver
Product: Red Hat OpenStack Reporter: Ram Raja <rraja>
Component: openstack-tripleo-heat-templatesAssignee: Ram Raja <rraja>
Status: CLOSED ERRATA QA Contact: Dustin Schoenbrun <dschoenb>
Severity: medium Docs Contact: mmurray
Priority: medium    
Version: 13.0 (Queens)CC: cschwede, gfidente, joflynn, jschluet, knylande, mburns, pgrist, rraja, tbarron, vimartin
Target Milestone: z2Keywords: Triaged, ZStream
Target Release: 13.0 (Queens)   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: openstack-tripleo-heat-templates-8.0.3-2.el7ost Doc Type: Bug Fix
Doc Text:
In CephFS-NFS driver deployments, the NFS-Ganesha server, backed by CephFS, performs dentry, inode, and attribute caching that is also performed by the libcephfs clients. The NFS-Ganesha server's redundant caching led to a large memory footprint. It also affected cache coherency. Turn off NFS-Ganesha server's inode, dentry, and attribute caching. This reduces the memory footprint of the NFS-Ganesha server. Cache coherency issues are less probable.
Story Points: ---
Clone Of: Environment:
Last Closed: 2018-08-29 16:35:26 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1570878    
Bug Blocks:    

Description Ram Raja 2018-04-14 15:30:50 UTC
Description of problem:

When setting up CephFS-NFS Manila driver, we want to tune NFS-Ganesha such that it doesn't cache the same information that libcephfs client caches. This is important to reduce the memory footprint of NFS-Ganesha, which runs along with other services such as Ceph MONs, MDSs, and OpenStack services in the controller node.  Minor changes are needed (at least) in ceph-ansible and OSP-director to set up Ganesha config such as dentry and attribute caching done by Ganesha is turned off as much as possible.

Comment 15 Ram Raja 2018-07-31 14:52:27 UTC
For verification,

Check whether the following setting are included in the ganesha.conf file used by the ganesha server,

# To disable caching
CACHEINODE {
	Dir_Max = 1;
	Dir_Chunk = 0;
	Cache_FDs = false;
	NParts = 1;
	Cache_Size = 1;
}


EXPORT_DEFAULTS {
	Attr_Expiration_Time = 0;
}


Also, check ganesha's log file for any warnings about the above config setting not being recognized by the ganesha server. There shouldn't be any. This is because the ganesha server doesn't error out if it can't recognize a setting, instead it logs a warning in the log file saying so.
e.g.,

[main] config_errs_to_log :CONFIG :WARN :Config File (/etc/ganesha/ganesha.conf:10): Unknown parameter (Attr_Expiration_Time)

Comment 16 Joanne O'Flynn 2018-08-15 07:56:34 UTC
This bug is marked for inclusion in the errata but does not currently contain draft documentation text. To ensure the timely release of this advisory please provide draft documentation text for this bug as soon as possible.

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Comment 18 errata-xmlrpc 2018-08-29 16:35:26 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:2574

Comment 19 Tom Barron 2018-09-05 20:21:51 UTC
With puddle 2018-08-22.2 and 8.0.4-20.el7ost the verification criteria from https://bugzilla.redhat.com/show_bug.cgi?id=1567511#c15 are met:

[root@controller-0 ~]# docker exec ceph-nfs-pacemaker grep -B 1 -A 12 'Attr_Expiration' /etc/ganesha/ganesha.conf
EXPORT_DEFAULTS {
	Attr_Expiration_Time = 0;
}

CACHEINODE {
	Dir_Max = 1;
	Dir_Chunk = 0;

	Cache_FDs = false;

	NParts = 1;
	Cache_Size = 1;
}

[root@controller-0 ~]# docker exec ceph-nfs-pacemaker grep WARN /var/log/ganesha/ganesha.log
05/09/2018 16:54:44 : epoch 5b900a54 : controller-0 : ganesha.nfsd-137[main] main :NFS STARTUP :WARN :No export entries found in configuration file !!!
05/09/2018 16:54:44 : epoch 5b900a54 : controller-0 : ganesha.nfsd-137[main] nfs_rpc_cb_init_ccache :NFS STARTUP :WARN :gssd_refresh_krb5_machine_credential failed (-1765328160:0)
[root@controller-0 ~]#