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>:3260
This 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