[Pacemaker] Two node cluster and no hardware device for stonith.

[Andrea]

Andrea <a.bacchi at ...> writes:

> 
> Michael Schwartzkopff <ms <at> ...> writes:
> 
> > 
> > Am Donnerstag, 22. Januar 2015, 10:03:38 schrieb E. Kuemmerle:
> > > On 21.01.2015 11:18 Digimer wrote:
> > > > On 21/01/15 08:13 AM, Andrea wrote:
> > > >> > Hi All,
> > > >> > 
> > > >> > I have a question about stonith
> > > >> > In my scenarion , I have to create 2 node cluster, but I don't 
> > 
> > Are you sure that you do not have fencing hardware? Perhaps you just did
nit 
> > configure it? Please read the manual of you BIOS and check your system
> board if 
> > you have a IPMI interface.
> > 
> 
> > > >> > In my test, when I simulate network failure, split brain occurs, and
> > > >> > when
> > > >> > network come back, One node kill the other node
> > > >> > -log on node 1:
> > > >> > Jan 21 11:45:28 corosync [CMAN  ] memb: Sending KILL to node 2
> > > >> > 
> > > >> > -log on node 2:
> > > >> > Jan 21 11:45:28 corosync [CMAN  ] memb: got KILL for node 2
> > 
> > That is how fencing works.
> > 
> > Mit freundlichen Grüßen,
> > 
> > Michael Schwartzkopff
> > 
> 
> Hi All
> 
> many thanks for your replies.
> I will update my scenario to ask about adding some devices for stonith
> - Option 1
> I will ask for having 2 vmware virtual machine, so i can try fance_vmware
> -Option 2
> In the project, maybe will need a shared storage. In this case, the shared
> storage will be a NAS that a can add to my nodes via iscsi. In this case I
> can try fence_scsi
> 
> I will write here about news
> 
> Many thanks  to all for support
> Andrea
> 
 


some news

- Option 2
In the customer environment I configured a iscsi target that our project
will use as cluster filesystem

[ONE]pvcreate /dev/sdb
[ONE]vgcreate -Ay -cy cluster_vg /dev/sdb
[ONE]lvcreate -L*G -n cluster_lv cluster_vg
[ONE]mkfs.gfs2 -j2 -p lock_dlm -t ProjectHA:ArchiveFS /dev/cluster_vg/cluster_lv

now I can add a Filesystem resource 

[ONE]pcs resource create clusterfs Filesystem
device="/dev/cluster_vg/cluster_lv" directory="/var/mountpoint"
fstype="gfs2" "options=noatime" op monitor interval=10s clone interleave=true

and I can read and write from both node.


Now I'd like to use this device with fence_scsi. 
It is ok? because I see in the man page this:
"The fence_scsi agent works by having each node in the cluster register a
unique key with the SCSI devive(s). Once registered, a single node will
become the reservation holder by creating  a  "write  exclu-sive, 
registrants only" reservation on the device(s). The result is that only
registered nodes may write to the device(s)"
It's no good for me, I need both node can write on the device.
So, I need another device to use with fence_scsi? In this case I will try to
create two partition, sdb1 and sdb2, on this device and use sdb1 as
clusterfs and sdb2 for fencing.


If i try to manually test this, I obtain before any operation 
[ONE]sg_persist -n --read-keys
--device=/dev/disk/by-id/scsi-36e843b608e55bb8d6d72d43bfdbc47d4
  PR generation=0x27, 1 registered reservation key follows:
    0x98343e580002734d


Then, I try to set serverHA1 key
[serverHA1]fence_scsi -d
/dev/disk/by-id/scsi-36e843b608e55bb8d6d72d43bfdbc47d4 -f /tmp/miolog.txt -n
serverHA1 -o on

But nothing has changed
[ONE]sg_persist -n --read-keys
--device=/dev/disk/by-id/scsi-36e843b608e55bb8d6d72d43bfdbc47d4
  PR generation=0x27, 1 registered reservation key follows:
    0x98343e580002734d


and in the log:
gen 26 17:53:27 fence_scsi: [debug] main::do_register_ignore
(node_key=4d5a0001, dev=/dev/sde)
gen 26 17:53:27 fence_scsi: [debug] main::do_reset (dev=/dev/sde, status=6)
gen 26 17:53:27 fence_scsi: [debug] main::do_register_ignore (err=0)

The same when i try on serverHA2
It is normal?


In any case, i try to create a stonith device
[ONE]pcs stonith create iscsi-stonith-device fence_scsi
pcmk_host_list="serverHA1 serverHA2"
devices=/dev/disk/by-id/scsi-36e843b608e55bb8d6d72d43bfdbc47d4 meta
provides=unfencing

and the cluster status is ok
[ONE] pcs status
Cluster name: MyCluHA
Last updated: Tue Jan 27 11:21:48 2015
Last change: Tue Jan 27 10:46:57 2015
Stack: cman
Current DC: serverHA1 - partition with quorum
Version: 1.1.11-97629de
2 Nodes configured
5 Resources configured


Online: [ serverHA1 serverHA2 ]

Full list of resources:

 Clone Set: ping-clone [ping]
     Started: [ serverHA1 serverHA2 ]
 Clone Set: clusterfs-clone [clusterfs]
     Started: [ serverHA1 serverHA2 ]
 iscsi-stonith-device	(stonith:fence_scsi):	Started serverHA1 



How I can try this from remote connection?


Andrea