Hi mike, I enable rbd admin sockets according to your suggestions, I add admin
socket option in my ceph.conf, but in /var/run/ceph directory , there is no
asok file, I used to nova to boot instances. Below is my steps to enable rbd
admin socket. If there is something wrong, please let me know:
1: add rbd admin socket to /etc/ceph/ceph.conf, here is my ceph.conf on client
hosts
[global]
log file = /var/log/ceph/$name.log
max open files = 131072
auth cluster required = none
auth service required = none
auth client required = none
rbd cache = true
debug perfcounter = 20
[client.volumes]
admin socket=/var/run/ceph/rbd-$pid.asok
[mon.a]
host = {monitor_host_name}
mon addr = {monitor_host_addr}
2: modify in /etc/apparmor.d/abstractions/libvirt-qemu
Add
# for rbd
capability mknod,
# for rbd
/etc/ceph/ceph.conf r,
/var/log/ceph/* rw,
/var/run/ceph/** rw,
Then restart libvirt-bin and nova-compute service
3: recreate nova instances and attach rbd, then execute 'dd if=/dev/zero
of=/dev/vdb bs=64k', after that, check /var/run/ceph/rbd-$pid.asok socket, but
it did not exist.
My ceph version was cuttlefish. Openstack is folsom. Is there anything wired
for you? Please let me know.
-----Original Message-----
From: Mike Dawson [mailto:[email protected]]
Sent: Tuesday, November 26, 2013 12:41 AM
To: Shu, Xinxin
Cc: Gregory Farnum; Mark Nelson; [email protected]
Subject: Re: [ceph-users] how to enable rbd cache
Greg is right, you need to enable RBD admin sockets. This can be a bit tricky
though, so here are a few tips:
1) In ceph.conf on the compute node, explicitly set a location for the admin
socket:
[client.volumes]
admin socket = /var/run/ceph/rbd-$pid.asok
In this example, libvirt/qemu is running with permissions from
ceph.client.volumes.keyring. If you use something different, adjust
accordingly. You can put this under a more generic [client] section, but there
are some downsides (like a new admin socket for each ceph cli command).
2) Watch for permissions issues creating the admin socket at the path you used
above. For me, I needed to explicitly grant some permissions in
/etc/apparmor.d/abstractions/libvirt-qemu, specifically I had to add:
# for rbd
capability mknod,
and
# for rbd
/etc/ceph/ceph.conf r,
/var/log/ceph/* rw,
/{,var/}run/ceph/** rw,
3) Be aware that if you have multiple rbd volumes attached to a single rbd
image, you'll only get an admin socket to the volume mounted last.
If you can set admin_socket via the libvirt xml for each volume, you can avoid
this issue. This thread will explain better:
http://www.mail-archive.com/[email protected]/msg16168.html
4) Once you get an RBD admin socket, query it like:
ceph --admin-daemon /var/run/ceph/rbd-29050.asok config show | grep rbd
Cheers,
Mike Dawson
On 11/25/2013 11:12 AM, Gregory Farnum wrote:
> On Mon, Nov 25, 2013 at 5:58 AM, Mark Nelson <[email protected]> wrote:
>> On 11/25/2013 07:21 AM, Shu, Xinxin wrote:
>>>
>>> Recently , I want to enable rbd cache to identify performance
>>> benefit. I add rbd_cache=true option in my ceph configure file, I
>>> use 'virsh attach-device' to attach rbd to vm, below is my vdb xml file.
>>
>>
>> Ceph configuration files are a bit confusing because sometimes you'll
>> see something like "rbd_cache" listed somewhere but in the ceph.conf
>> file you'll want a space instead:
>>
>> rbd cache = true
>>
>> with no underscore. That should (hopefully) fix it for you!
>
> I believe the config file will take either format.
>
> The RBD cache is a client-side thing, though, so it's not ever going
> to show up in the OSD! You want to look at the admin socket created by
> QEMU (via librbd) to see if it's working. :) -Greg -Greg
>
>>
>>>
>>> <disk type='network' device='disk'>
>>>
>>> <driver name='qemu' type='raw' cache='writeback'/>
>>>
>>> <source protocol='rbd'
>>>
>>> name='rbd/node12_2:rbd_cache=true:rbd_cache_writethrough_until_flush
>>> =true'/>
>>>
>>> <target dev='vdb' bus='virtio'/>
>>>
>>> <serial>6b5ff6f4-9f8c-4fe0-84d6-9d795967c7dd</serial>
>>>
>>> <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
>>> function='0x0'/>i
>>>
>>> </disk>
>>>
>>> I do not know this is ok to enable rbd cache. I see perf counter for
>>> rbd cache in source code, but when I used admin daemon to check rbd
>>> cache statistics,
>>>
>>> Ceph -admin-daemon /var/run/ceph/ceph-osd.0.asok perf dump
>>>
>>> But I did not get any rbd cahce flags.
>>>
>>> My question is how to enable rbd cahce and check rbd cache perf
>>> counter, or how can I make sure rbd cache is enabled, any tips will
>>> be appreciated? Thanks in advanced.
>>>
>>>
>>>
>>> _______________________________________________
>>> ceph-users mailing list
>>> [email protected]
>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>
>>
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