Starting with GlusterFS 3.4.0 there is a an API which can be used to access files on a GlusterFS volume directly without the FUSE-mount. Qemu supports this , starting from with version 1.23.0.
= GlusterFS =
'''NOTE: this got implemented in stoney cloud 1.2.10.4 and you should not have to perform the following steps.'''
Since we run Qemu as unprivileged user we have to permit access to GlusterFS from an unprivileged port as well as an unprivileged user.
To achieve that, add the following line to the <code>volume management</code> in <code>/etc/glusterfs/glusterd.vol</code> on all involved storage nodes and restart glusterd:
<pre>
option rpc-auth-allow-insecure on
<pre>
gluster volume set virtualization server.allow-insecure On
</pre>
After that you should at least restart <code>glusterd</code>:
<pre>
/etc/init.d/glusterd restart
</pre>
But it seems that one also has to restart all <code>glusterfsd</code> daemons by restarting the volume. So, do the following on a GlusterFS node:
<pre>
gluster volume stop virtualization
gluster volume start virtualization
</pre>
= Libvirt =
The XML has to be changed only slightly. Following is an example:.
'''current'''<presyntaxhighlight lang='xml'> <disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='none'/> <source file='/var/virtualization/vm-templates/5b77d2f6-061f-410c-8ee7-9e61da6f1927/f3d87cf9-f7d8-4224-b908-cc9fc6c8fcd4.qcow2'/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </disk></syntaxhighlight> '''direct-gluster-access'''<syntaxhighlight lang='xml'>
<disk type='network' device='disk'>
<driver name='qemu' type='qcow2' cache='none'/>
<source protocol='gluster' name='virtualization/vm-templates/5b77d2f6-061f-410c-8ee7-9e61da6f1927/f3d87cf9-f7d8-4224-b908-cc9fc6c8fcd4.qcow2'>
<host name='10.1.120.11'/>
</source>
<target dev='vda' bus='virtio'/>
<alias name='virtio-disk0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
</disk>
</presyntaxhighlight>
What changesThe changed elements are: ;<code>disk-type</code>:has to be <code>network</code> instead of <code>file</code>
;<code>source</code>:has now a <code>protocol</code> and a <code>name</code> instead of a <code>file</code> attribute as well as a new subelement <code>host</code>, where the <code>name</code> is the filename without <code>/var/</code>
= LDAP =
== Current ==
<syntaxhighlight lang='ldif'>
dn: sstDisk=vda,ou=devices,sstVirtualMachine=ece1eab1-4a9e-4729-bfc1-59d9f01550a5,ou=virtual machines,ou=virtualization,ou=services,dc=foss-cloud,dc=org
objectclass: top
objectclass: sstVirtualizationVirtualMachineDisk
sstType: file
sstDevice: disk
sstDriverName: qemu
sstDriverType: qcow2
sstDriverCache: none
sstVolumeName: 3aa376a5-6d09-442b-8662-425de888385b
sstSourceFile: /var/virtualization/vm-persistent/0f83f084-8080-413e-b558-b678e504836e/3aa376a5-6d09-442b-8662-425de888385b.qcow2
sstDisk: vda
sstTargetBus: virtio
sstReadonly: FALSE
sstVolumeAllocation: 0
sstVolumeCapacity: 32212254720
</syntaxhighlight>
== New ==
<syntaxhighlight lang='ldif'>
dn: sstDisk=vda,ou=devices,sstVirtualMachine=ece1eab1-4a9e-4729-bfc1-59d9f01550a5,ou=virtual machines,ou=virtualization,ou=services,dc=foss-cloud,dc=org
objectclass: top
objectclass: sstVirtualizationVirtualMachineDisk
sstType: network -> instead of file
sstDevice: disk
sstDriverName: qemu
sstDriverType: qcow2
sstDriverCache: none
sstVolumeName: 3aa376a5-6d09-442b-8662-425de888385b
sstSourceProtocol: gluster -> new
sstSourceName: virtualization/vm-persistent/0f83f084-8080-413e-b558-b678e504836e/3aa376a5-6d09-442b-8662-425de888385b.qcow2 -> new attribute
sstSourceHostName: 10.1.120.11 -> new and multi-valued attribute (for later use, currently, only one entry is supported)
sstDisk: vda
sstTargetBus: virtio
sstReadonly: FALSE
sstVolumeAllocation: 0
sstVolumeCapacity: 32212254720
</syntaxhighlight>
== Notes for Configuration in LDAP ==
=== Persistent Storage Pool ===
<syntaxhighlight lang='ldif'>
sstStoragePool=0f83f084-8080-413e-b558-b678e504836e,ou=storage pools,ou=virtualization,ou=services,o=stepping-stone,c=ch
</syntaxhighlight>
==== file ====
<syntaxhighlight lang='ldif'>
sstStoragePoolURI: file:///var/virtualization/vm-persistent/0f83f084-8080-413e-b558-b678e504836e
</syntaxhighlight>
==== gluster ====
<syntaxhighlight lang='ldif'>
sstStoragePoolURI: gluster:///tier1-storage-node-01/gv-tier1-vm-01/vm-persistent/0f83f084-8080-413e-b558-b678e504836e
</syntaxhighlight>
=== Questions / Open Issues ===
* Where do we store the following configuration values?
** Possible storage pool types: file, gluster (others could follow)
** Host names or ip addresses (in case of gluster): tier1-storage-node-01
** Mount point: /var/virtualization/vm-persistent/ or /gv-tier1-vm-01/vm-persistent/
** Storage Pool Names: 0f83f084-8080-413e-b558-b678e504836e
** Where and how to we store the information, that we have slow and fast storage?
= Test =
Birth: -
</pre>
== qemu ==
The following qemu commandline is generated by libvirt, minus the network device, the <code>-S</code> parameter and with disabled spice password and should give a running VM, given that the specified VM images exist:
<pre>
/usr/bin/qemu-system-x86_64 \
-machine accel=kvm \
-name e35422fa-18e7-41eb-8478-d09daff1b43a \
-machine pc-1.3,accel=kvm,usb=off \
-m 2048 \
-realtime mlock=off \
-smp 1,sockets=1,cores=1,threads=1 \
-uuid e35422fa-18e7-41eb-8478-d09daff1b43a \
-no-user-config \
-nodefaults \
-chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/e35422fa-18e7-41eb-8478-d09daff1b43a.monitor,server,nowait \
-mon chardev=charmonitor,id=monitor,mode=control \
-rtc base=utc \
-no-shutdown \
-device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x8.0x7 \
-device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x8 \
-device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x8.0x1 \
-device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x8.0x2 \
-device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 \
-drive file=gluster://10.1.120.11/virtualization/iso/a51f5193-f518-4cb6-8d5b-f24538543217.iso,if=none,id=drive-ide0-0-1,readonly=on,format=raw \
-device ide-cd,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1 \
-drive file=gluster://10.1.120.11/virtualization/vm-templates/5b77d2f6-061f-410c-8ee7-9e61da6f1927/f3d87cf9-f7d8-4224-b908-cc9fc6c8fcd4.qcow2,if=none,id=drive-virtio-disk0,format=qcow2,cache=none \
-device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 \
-chardev spicevmc,id=charchannel0,name=vdagent \
-device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 \
-device usb-tablet,id=input0 \
-spice port=5900,addr=192.168.140.13,seamless-migration=on,disable-ticketing \
-vga qxl \
-global qxl-vga.ram_size=67108864 \
-global qxl-vga.vram_size=67108864 \
-device AC97,id=sound0,bus=pci.0,addr=0x4 \
-chardev spicevmc,id=charredir0,name=usbredir \
-device usb-redir,chardev=charredir0,id=redir0,filter=-1:-1:-1:-1:0 \
-chardev spicevmc,id=charredir1,name=usbredir \
-device usb-redir,chardev=charredir1,id=redir1,filter=-1:-1:-1:-1:0 \
-chardev spicevmc,id=charredir2,name=usbredir \
-device usb-redir,chardev=charredir2,id=redir2,filter=-1:-1:-1:-1:0 \
-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7
</pre>
= Troubleshooting =
== Qemu hang ==
Should Qemu hang after start, check the brick logfile (in our default setup this would be <code>/var/log/glusterfs/bricks/var-data-gluster-volume-01.log</code>) for the following entries:
<pre>
[2013-08-04 11:02:34.022328] E [addr.c:152:gf_auth] 0-auth/addr: client is bound to port 50037 which is not privileged
[2013-08-04 11:02:34.022362] E [authenticate.c:239:gf_authenticate] 0-auth: no authentication module is interested in accepting remote-client (null)
[2013-08-04 11:02:34.022410] E [server-handshake.c:578:server_setvolume] 0-virtualization-server: Cannot authenticate client from foss-cloud-node-01-12502-2013/08/04-11:02:33:989625-virtualization-clie
nt-1-0 3.4.0
</pre>
This means that one of the configuration options from above didn't work and/or you forgot to restart <code>glusterd</code> or the volume.
= Caveats =
== Number of GlusterFS servers ==
At the moment it is not possible to specify more than one server.
== libvirt integration ==
Libvirt is supposed to be able to create images on a GlusterFS. But a storage pool must be set up first with the appropriate configuration.
[[Category:Snippets]]