Hi!
I'm new to libvirt and face problems connecting to an iSCSI target.
What I intend to do is to connect libvirt (I tried virt-manager and
virsh) to an iSCSI target and then boot from the LUNs which contain
the VMs.
I followed the documentation¹ but got stuck at section 12.1.5.4.3.
1)
virsh pool-define-as \
--name foo \
--type iscsi \
--source-host vmhost \
--source-dev iqn.2013-11.vmhost:vmpool \
--target /dev/disk/by-path
2)
virsh pool-start foo
error: Failed to start pool foo
error: internal error: cannot find session
virsh -c qemu:///system pool-start foo
error: Failed to start pool foo
error: internal error: cannot find session
Why can't libvirt find the session, and which session? Running
iscsiadm --mode discovery --type sendtargets --portal vmhost:3260,1
succeeds and lists the targets. How to connect libvirt to the iSCSI
target?
System info:
Debian sid, Linux 3.11-2-amd64
libvirtd (libvirt) 1.1.4
virsh version: 1.1.4
iSCSI target: FreeNAS-9.1.1
Best regards
Marco
¹
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/chap-Virtualization_Administration_Guide-Storage_Pools-Storage_Pools.html#sect-Virtualization-Storage_Pools-Creating-iSCSI
On 2013–12–18 Marco wrote:> virsh pool-start foo > error: Failed to start pool foo > error: internal error: cannot find session > > virsh -c qemu:///system pool-start foo > error: Failed to start pool foo > error: internal error: cannot find session > > Why can't libvirt find the session, and which session?Any ideas? Shall I provide more information? Best regards Marco
On 12/17/2013 07:13 PM, Marco wrote:> Hi! > > I'm new to libvirt and face problems connecting to an iSCSI target. > What I intend to do is to connect libvirt (I tried virt-manager and > virsh) to an iSCSI target and then boot from the LUNs which contain > the VMs. > > I followed the documentation¹ but got stuck at section 12.1.5.4.3. > > 1) > virsh pool-define-as \ > --name foo \ > --type iscsi \ > --source-host vmhost \ > --source-dev iqn.2013-11.vmhost:vmpool \ > --target /dev/disk/by-path > > 2) > virsh pool-start foo > error: Failed to start pool foo > error: internal error: cannot find session > > virsh -c qemu:///system pool-start foo > error: Failed to start pool foo > error: internal error: cannot find session >I'm assuming 'vmhost' is actually some valid IP Address/Name that you're just using here to hide from the world your actual iSCSI tgt server. Don't forget that the 'source-host' may be listed as 'host1.example.com'; however, the iqn has 'com.example.host1'. IOW - reversed... Have you looked at http://libvirt.org/formatstorage.html ? There's an example there of output that works for me. Use virsh pool-dumpxml <pool> to view the XML... Also, do you need to authenticate to the iSCSI target? The iscsiadm will use '/etc/iscsi/iscsid.conf'. See the node.session.auth.{authmethod | username | password} fields, so while iscsiadm may work, when libvirt goes to connect it fails. Looking at the output in the system messages log may help (for my f19 /var/log/messages). You may also find if you have selinux enabled as Enforcing there could be more configuration that you need (if the iSCSI tgtd is local). Setting up a label on the file - something I'm not an expert at... Another tool to try is 'iscsi-ls' from package 'libiscsi-utils' iscsi-ls -s -i iqn.2013-11.vmhost:vmpool \ iscsi://<username>%<password>@<ipAddr>:3260 where the <username>/<password> allow the authentication to the ipAddr iSCSI tgt server. If you need to authenticate, then set up a secret to the iSCSI server, see http://libvirt.org/formatsecret.html for an example. HTH, John> Why can't libvirt find the session, and which session? Running > > iscsiadm --mode discovery --type sendtargets --portal vmhost:3260,1 > > succeeds and lists the targets. How to connect libvirt to the iSCSI > target? > > System info: > > Debian sid, Linux 3.11-2-amd64 > libvirtd (libvirt) 1.1.4 > virsh version: 1.1.4What's your QEMU version?> > iSCSI target: FreeNAS-9.1.1 > > > Best regards > Marco > > ¹ https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/chap-Virtualization_Administration_Guide-Storage_Pools-Storage_Pools.html#sect-Virtualization-Storage_Pools-Creating-iSCSI > > _______________________________________________ > libvirt-users mailing list > libvirt-users@redhat.com > https://www.redhat.com/mailman/listinfo/libvirt-users >
On 2013–12–21 John Ferlan wrote:> On 12/17/2013 07:13 PM, Marco wrote: > > Hi! > > > > I'm new to libvirt and face problems connecting to an iSCSI target. > > What I intend to do is to connect libvirt (I tried virt-manager and > > virsh) to an iSCSI target and then boot from the LUNs which contain > > the VMs. > > > > I followed the documentation¹ but got stuck at section 12.1.5.4.3. > > > > 1) > > virsh pool-define-as \ > > --name foo \ > > --type iscsi \ > > --source-host vmhost \ > > --source-dev iqn.2013-11.vmhost:vmpool \ > > --target /dev/disk/by-path > > > > 2) > > virsh pool-start foo > > error: Failed to start pool foo > > error: internal error: cannot find session > > > > virsh -c qemu:///system pool-start foo > > error: Failed to start pool foo > > error: internal error: cannot find session > > > > I'm assuming 'vmhost' is actually some valid IP Address/Name that you're > just using here to hide from the world your actual iSCSI tgt server. > Don't forget that the 'source-host' may be listed as > 'host1.example.com'; however, the iqn has 'com.example.host1'. IOW - > reversed...It's a test setup and I don't use a FQDN.> Have you looked at http://libvirt.org/formatstorage.html ?I did, indeed.> There's an example there of output that works for me.For me it does not.> Use virsh pool-dumpxml <pool> > to view the XML...Here's my XML which is directly taken from the manual. I only changed the host name to “freenas” and the device path. <pool type='iscsi'> <name>virtimages</name> <uuid>347feb68-7e11-4f2b-ba82-ada027296fb0</uuid> <capacity unit='bytes'>0</capacity> <allocation unit='bytes'>0</allocation> <available unit='bytes'>0</available> <source> <host name='freenas'/> <device path='iqn.2013-11.freenas:vmpool'/> </source> <target> <path>/dev/disk/by-path</path> <permissions> <mode>0755</mode> <owner>-1</owner> <group>-1</group> </permissions> </target> </pool>> Also, do you need to authenticate to the iSCSI target?Not yet. To rule out authentication issues for testing I turned off authentication.> The iscsiadm will use '/etc/iscsi/iscsid.conf'. See the > node.session.auth.{authmethod | username | password} fields, so > while iscsiadm may work, when libvirt goes to connect it fails.Thanks for pointing that out, but I don't think it's the case here.> Looking at the output in the system messages > log may help (for my f19 /var/log/messages).The log of a failed virsh pool-start virtimages can be found here http://dpaste.com/1518444/ Most notable is I assume: libvirtd[8028]: internal error: Child process (/usr/bin/iscsiadm --mode session) unexpected exit status 21>From “man iscsiadm”:21 ISCSI_ERR_NO_OBJS_FOUND - no records/targets/sessions/portals found to execute operation on. If I run “iscsiadm --mode session” in the console, I indeed get and error: iscsiadm: No active sessions. Do I need to create a session or setup libvert to do that before iSCSI is supposed to work? The log shows that libvirt is able to connect to the target: iscsid: Connection85:0 to [target: iqn.2013-11.freenas:vmpool, portal: 10.0.10.23,3260] through [iface: libvirt-iface-04d9ea67] is operational now> You may also find if you have selinux enabled as Enforcing there could > be more configuration that you need (if the iSCSI tgtd is local). > Setting up a label on the file - something I'm not an expert at...selinux is not used.> Another tool to try is 'iscsi-ls' from package 'libiscsi-utils' > > iscsi-ls -s -i iqn.2013-11.vmhost:vmpool \ > iscsi://<username>%<password>@<ipAddr>:3260This succeeds: iscsi-ls -s -i iqn.2013-11.freenas:vmpool iscsi://freenas Target:iqn.2013-11.freenas:vmpool Portal:10.0.10.23:3260,1 Lun:0 Type:DIRECT_ACCESS (Size:9G) […]> If you need to authenticate, then set up a secret to the iSCSI server, > see http://libvirt.org/formatsecret.html for an example.If the simple setup is working I'll add authentication but for the moment I try to keep is as simple as possible. To rule out issues with the iSCSI target I manually tested using “iscsiadm” and VirtualBox which both succeeded without any session errors. Thanks for your quick response. Best regards Marco