Red Hat ENTERPRISE LINUX 5 - VIRTUALIZATION GUIDE Guia de Instalação descarregar pdf (Página 255)

Removable media: No

Readonly: No

Backing store type: rdwr

Backing store path: /var/lib/tgtd/kvmguest/shareddata.img

Backing store flags:

Account information:

ACL information:

4. Allo w clien t access t o t h e t arg et

Finally, this example command allows access to all clients without any authentication:

# tgtadm --lld iscsi --op bind --mode target --tid 1 --initiator-address ALL

Note

The two most common problems encountered when configuring the iSCSI target are related to

SELinux and iptables. If adding plain files as LUNs in an iSCSI target, ensure the files are

labeled system_u:object_r:tgtd_var_lib_t:s0. TCP port 3260 must be open in your

iptables configuration.

24 .1.2. How t o configure iSCSI on a libvirt KVM host and provision a guest

using virt -inst all

The previous section described how to set up an iSCSI target. This section demonstrates how to

configure iSCSI on a libvirt KVM instance using virsh, and then how to provision a guest using

virt-install.

1. Def in in g t h e st orag e po o l

All libvirt storage is managed through storage pools, of which there are many possible types:

SCSI, NFS, ext4, plain directory and iSCSI. All libvirt objects are configured via XML

description files, and storage pools are no different in this regard. For an iSCSI storage pool

there are three important pieces of information to provide:

The target path - this determines how libvirt will expose device paths for the pool. Paths like

/dev/sda and /dev/sdb are not an ideal choice as they can change between reboots,

and can change across machines within a cluster; in other words, the names are

assigned on a first come, first served basis by the kernel. It is strongly recommended to

use the /dev/disk/by-path format. This results in a consistent naming scheme across

all machines.

The host name - this is the fully-qualified DNS name of the iSCSI server.

The source path - this is the iSCSI qualified name (IQN) seen in the previous setup

procedure (iqn.2004-04.rhel:rhel5:iscsi.kvmguest).

Although your environment will likely be different, the following text is what an iSCSI

configuration will look like:

<name>kvmguest</name>

⁠Chapt er 2 4 . Using shared st orag e wit h virt ual disk images

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Red Hat ENTERPRISE LINUX 5 - VIRTUALIZATION GUIDE Guia de Instalação Página 255