[ClusterLabs] [pacemaker+ clvm] Cluster lvm must be active exclusively to create snapshot
su liu
liusu8788 at gmail.com
Tue Dec 6 07:43:17 CET 2016
hello digimer，
I am happy to tell you that I got the reason why I can not access the LVs
on the compute1 node.
Because I make a mistake with thc /etc/lvm/lvm.con on the compute1 node.
Now it works.
Then I would to study how to snapshotting a LV.
Thank you!
2016-12-06 14:24 GMT+08:00 su liu <liusu8788 at gmail.com>:
> It is the resource configration whthin my pacemaker cluster:
>
> [root at controller ~]# cibadmin --query --scope resources
> <resources>
> <clone id="dlm-clone">
> <primitive class="ocf" id="dlm" provider="pacemaker" type="controld">
> <instance_attributes id="dlm-instance_attributes">
> <nvpair id="dlm-instance_attributes-allow_stonith_disabled"
> name="allow_stonith_disabled" value="true"/>
> </instance_attributes>
> <operations>
> <op id="dlm-start-interval-0s" interval="0s" name="start"
> timeout="90"/>
> <op id="dlm-stop-interval-0s" interval="0s" name="stop"
> timeout="100"/>
> <op id="dlm-monitor-interval-30s" interval="30s" name="monitor"/>
> </operations>
> </primitive>
> <meta_attributes id="dlm-clone-meta_attributes">
> <nvpair id="dlm-interleave" name="interleave" value="true"/>
> <nvpair id="dlm-ordered" name="ordered" value="true"/>
> </meta_attributes>
> </clone>
> <clone id="clvmd-clone">
> <primitive class="ocf" id="clvmd" provider="heartbeat" type="clvm">
> <instance_attributes id="clvmd-instance_attributes">
> <nvpair id="clvmd-instance_attributes-activate_vgs"
> name="activate_vgs" value="true"/>
> </instance_attributes>
> <operations>
> <op id="clvmd-start-interval-0s" interval="0s" name="start"
> timeout="90"/>
> <op id="clvmd-stop-interval-0s" interval="0s" name="stop"
> timeout="90"/>
> <op id="clvmd-monitor-interval-30s" interval="30s"
> name="monitor"/>
> </operations>
> <meta_attributes id="clvmd-meta_attributes"/>
> </primitive>
> <meta_attributes id="clvmd-clone-meta_attributes">
> <nvpair id="clvmd-interleave" name="interleave" value="true"/>
> <nvpair id="clvmd-ordered" name="ordered" value="true"/>
> </meta_attributes>
> </clone>
> </resources>
> [root at controller ~]#
>
>
>
> 2016-12-06 14:16 GMT+08:00 su liu <liusu8788 at gmail.com>:
>
>> Thank you very much.
>>
>> Because I am new to pacemaker, and I have checked the docs that
>> additional devices are needed when configing stonith, but now I does not
>> have it in my environment.
>>
>> I will see how to config it afterward.
>>
>> Now I want to know how the cluster LVM works. Thank you for your patience
>> explanation.
>>
>> The scene is:
>>
>> controller node + compute1 node
>>
>> I mount a SAN to both controller and compute1 node. Then I run a
>> pacemaker + corosync + clvmd cluster:
>>
>> [root at controller ~]# pcs status --full
>> Cluster name: mycluster
>> Last updated: Tue Dec 6 14:09:59 2016 Last change: Mon Dec 5 21:26:02
>> 2016 by root via cibadmin on controller
>> Stack: corosync
>> Current DC: compute1 (2) (version 1.1.13-10.el7_2.4-44eb2dd) - partition
>> with quorum
>> 2 nodes and 4 resources configured
>>
>> Online: [ compute1 (2) controller (1) ]
>>
>> Full list of resources:
>>
>> Clone Set: dlm-clone [dlm]
>> dlm (ocf::pacemaker:controld): Started compute1
>> dlm (ocf::pacemaker:controld): Started controller
>> Started: [ compute1 controller ]
>> Clone Set: clvmd-clone [clvmd]
>> clvmd (ocf::heartbeat:clvm): Started compute1
>> clvmd (ocf::heartbeat:clvm): Started controller
>> Started: [ compute1 controller ]
>>
>> Node Attributes:
>> * Node compute1 (2):
>> * Node controller (1):
>>
>> Migration Summary:
>> * Node compute1 (2):
>> * Node controller (1):
>>
>> PCSD Status:
>> controller: Online
>> compute1: Online
>>
>> Daemon Status:
>> corosync: active/disabled
>> pacemaker: active/disabled
>> pcsd: active/enabled
>>
>>
>>
>> step 2:
>>
>> I create a cluster VG:cinder-volumes:
>>
>> [root at controller ~]# vgdisplay
>> --- Volume group ---
>> VG Name cinder-volumes
>> System ID
>> Format lvm2
>> Metadata Areas 1
>> Metadata Sequence No 44
>> VG Access read/write
>> VG Status resizable
>> Clustered yes
>> Shared no
>> MAX LV 0
>> Cur LV 0
>> Open LV 0
>> Max PV 0
>> Cur PV 1
>> Act PV 1
>> VG Size 1000.00 GiB
>> PE Size 4.00 MiB
>> Total PE 255999
>> Alloc PE / Size 0 / 0
>> Free PE / Size 255999 / 1000.00 GiB
>> VG UUID aLamHi-mMcI-2NsC-Spjm-QWZr-MzHx-pPYSTt
>>
>> [root at controller ~]#
>>
>>
>> Step 3 :
>>
>> I create a LV and I want it can be seen and accessed on the compute1 node
>> but it is failed:
>>
>> [root at controller ~]# lvcreate --name test001 --size 1024m cinder-volumes
>> Logical volume "test001" created.
>> [root at controller ~]#
>> [root at controller ~]#
>> [root at controller ~]# lvs
>> LV VG Attr LSize Pool Origin Data% Meta% Move
>> Log Cpy%Sync Convert
>> test001 cinder-volumes -wi-a----- 1.00g
>>
>> [root at controller ~]#
>> [root at controller ~]#
>> [root at controller ~]# ll /dev/cinder-volumes/test001
>> lrwxrwxrwx 1 root root 7 Dec 6 14:13 /dev/cinder-volumes/test001 ->
>> ../dm-0
>>
>>
>>
>> I can access it on the contrller node, but on the comput1 node, I can see
>> it with lvs command .but cant access it with ls command, because it is not
>> exists on the /dev/cinder-volumes directory:
>>
>>
>> [root at compute1 ~]# lvs
>> LV VG Attr LSize Pool Origin Data% Meta% Move
>> Log Cpy%Sync Convert
>> test001 cinder-volumes -wi------- 1.00g
>>
>> [root at compute1 ~]#
>> [root at compute1 ~]#
>> [root at compute1 ~]# ll /dev/cinder-volumes
>> ls: cannot access /dev/cinder-volumes: No such file or directory
>> [root at compute1 ~]#
>> [root at compute1 ~]#
>> [root at compute1 ~]# lvscan
>> inactive '/dev/cinder-volumes/test001' [1.00 GiB] inherit
>> [root at compute1 ~]#
>>
>>
>>
>> Is something error with my configuration besides stonith? Could you help
>> me? thank you very much.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> 2016-12-06 11:37 GMT+08:00 Digimer <lists at alteeve.ca>:
>>
>>> On 05/12/16 10:32 PM, su liu wrote:
>>> > Digimer, thank you very much!
>>> >
>>> > I do not need to have the data accessible on both nodes at once. I want
>>> > to use the clvm+pacemaker+corosync in OpenStack Cinder.
>>>
>>> I'm not sure what "cinder" is, so I don't know what it needs to work.
>>>
>>> > then only a VM need access the LV at once. But the Cinder service which
>>> > runs on the controller node is responsible for snapshotting the LVs
>>> > which are attaching on the VMs runs on other Compute nodes(such as
>>> > compute1 node).
>>>
>>> If you don't need to access an LV on more than one node at a time, then
>>> don't add clustered LVM and keep things simple. If you are using DRBD,
>>> keep the backup secondary. If you are using LUNs, only connect the LUN
>>> to the host that needs it at a given time.
>>>
>>> In HA, you always want to keep things as simple as possible.
>>>
>>> > Need I active the LVs in /exclusively mode all the time? to supoort
>>> > snapping it while attaching on the VM./
>>>
>>> If you use clustered LVM, yes, but then you can't access the LV on any
>>> other nodes... If you don't need clustered LVM, then no, you continue to
>>> use it as simple LVM.
>>>
>>> Note; Snapshoting VMs is NOT SAFE unless you have a way to be certain
>>> that the guest VM has flushed it's caches and is made crash safe before
>>> the snapshot is made. Otherwise, your snapshot might be corrupted.
>>>
>>> > /The following is the result when execute lvscan command on compute1
>>> node:/
>>> > /
>>> > /
>>> > /
>>> > [root at compute1 ~]# lvs
>>> > LV VG Attr
>>> > LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
>>> > volume-1b0ea468-37c8-4b47-a6fa-6cce65b068b5 cinder-volumes
>>> -wi-------
>>> > 1.00g
>>> >
>>> >
>>> >
>>> > and on the controller node:
>>> >
>>> > [root at controller ~]# lvscan ACTIVE
>>> > '/dev/cinder-volumes/volume-1b0ea468-37c8-4b47-a6fa-6cce65b068b5'
>>> [1.00
>>> > GiB] inherit
>>> >
>>> >
>>> >
>>> > thank you very much!
>>>
>>> Did you setup stonith? If not, things will go bad. Not "if", only
>>> "when". Even in a test environment, you _must_ setup stonith.
>>>
>>> --
>>> Digimer
>>> Papers and Projects: https://alteeve.ca/w/
>>> What if the cure for cancer is trapped in the mind of a person without
>>> access to education?
>>>
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>>>
>>
>>
>
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