[Qemu-devel] (no subject)

[Qemu-devel] (no subject)

[Ronnie Sahlberg]

List,

Please find a patch that adds a new section for iSCSI to qemu-doc.

This section provides much more verbose description of iSCSI and its use than
the manpage and also includes a short description on how to set up a
simple iSCSI target on loopback and then accessing it from QEMU.

The example on how to set up iSCSI Target uses the STGT iscsi target,
so the example would only work on a subset of linux/bsd systems.
I recognize also that this might be controversion, since why show how to 
configure "xyz unrelated package" in QEMU documentation.
My intention here is to provide a howto that describes how to quickly get iSCSI target up and running and to get QEMU to use it. As a quick howto for people that are not familiar with iSCSI but still want to test it out quickly.

Learning how to set up iSCSI target can often be somewhat complex and daunting
and could otherwise act as huge treshold for people that would just want to
get iSCSI running and experiment with QMEU, but would otherwise not want to
spend a lot of time learning about the target side of iscsi.


I think having examples like this is useful but see that it could be seen as
controversial.
Feel free to remove that part of the patch if you think this does not belong in the qemu docs.


regards
ronnie sahlberg

[Qemu-devel] [PATCH] Documentation: Add section about iSCSI LUNS to qemu-doc

[Ronnie Sahlberg]

Add a new section about using iSCSI LUNs with qemu
and provide a short example on how to set up a target and access it
using the built-in initiator

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
---
 qemu-doc.texi |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/qemu-doc.texi b/qemu-doc.texi
index 149e9bd..c1b293e 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -421,6 +421,7 @@ snapshots.
 * disk_images_fat_images::    Virtual FAT disk images
 * disk_images_nbd::           NBD access
 * disk_images_sheepdog::      Sheepdog disk images
+* disk_images_iscsi::         iSCSI LUNs
 @end menu
 
 @node disk_images_quickstart
@@ -695,6 +696,58 @@ qemu-img create sheepdog:@var{hostname}:@var{port}:@var{image} @var{size}
 qemu sheepdog:@var{hostname}:@var{port}:@var{image}
 @end example
 
+@node disk_images_iscsi
+@subsection iSCSI LUNs
+
+iSCSI is a popular protocol used to access SCSI devices across a computer
+network. 
+
+There are two different ways iSCSI devices can be used by QEMU.
+
+The first method is to mount the iSCSI LUN on the host, and make it appear as
+any other ordinary SCSI device on the host and then to access this device as a
+/dev/sd device from QEMU. How to do this differs between host OSes.
+
+The second method involves using the iSCSI initiator that is built into
+QEMU. This provides a mechanism that works the same way regardless of which
+host OS you are running QEMU on. This section will describe this second method
+of using iSCSI together with QEMU.
+
+In QEMU, iSCSI devices are described using special iSCSI URLs
+
+@example
+URL syntax:
+iscsi://[<username>[%<password>]@@]<host>[:<port>]/<target-iqn-name>/<lun>
+@end example
+
+Username and password are optional and only used if your taget is set up
+using CHAP authentication for access control.
+Alternatively the username and passwords can also be set via environment
+variables to have these not show up in the process list
+
+@example
+export LIBISCSI_CHAP_USERNAME=<username>
+export LIBISCSI_CHAP_PASSWORD=<password>
+iscsi://<host>/<target-iqn-name>/<lun>
+@end example
+
+Howto set up a simple iSCSI target on loopback and accessing it via QEMU:
+@example
+Setting up a iSCSI target with one CDROM and one DISK:
+tgtd --iscsi portal=127.0.0.1:3260
+tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.qemu.test
+tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 \
+    -b /IMAGES/disk.img --device-type=disk
+tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 \
+    -b /IMAGES/cd.iso --device-type=cd
+tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
+
+qemu -boot d -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \
+    -cdrom iscsi://127.0.0.1/iqn.qemu.test/2
+@end example
+
+
+
 @node pcsys_network
 @section Network emulation
 
-- 
1.7.3.1

Re: [Qemu-devel] [PATCH] Documentation: Add section about iSCSI LUNS to qemu-doc

[Stefan Weil]

Hi,

I have only some small remarks, see my inline comments below.

Am 11.11.2011 22:46, schrieb Ronnie Sahlberg:
> Add a new section about using iSCSI LUNs with qemu
> and provide a short example on how to set up a target and access it
> using the built-in initiator
>
> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
> ---
> qemu-doc.texi | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 53 insertions(+), 0 deletions(-)
>
> diff --git a/qemu-doc.texi b/qemu-doc.texi
> index 149e9bd..c1b293e 100644
> --- a/qemu-doc.texi
> +++ b/qemu-doc.texi
> @@ -421,6 +421,7 @@ snapshots.
> * disk_images_fat_images:: Virtual FAT disk images
> * disk_images_nbd:: NBD access
> * disk_images_sheepdog:: Sheepdog disk images
> +* disk_images_iscsi:: iSCSI LUNs
> @end menu
>
> @node disk_images_quickstart
> @@ -695,6 +696,58 @@ qemu-img create 
> sheepdog:@var{hostname}:@var{port}:@var{image} @var{size}
> qemu sheepdog:@var{hostname}:@var{port}:@var{image}
> @end example
>
> +@node disk_images_iscsi
> +@subsection iSCSI LUNs
> +
> +iSCSI is a popular protocol used to access SCSI devices across a computer
> +network.
> +
> +There are two different ways iSCSI devices can be used by QEMU.
> +
> +The first method is to mount the iSCSI LUN on the host, and make it 
> appear as
> +any other ordinary SCSI device on the host and then to access this 
> device as a
> +/dev/sd device from QEMU. How to do this differs between host OSes.
> +
> +The second method involves using the iSCSI initiator that is built into
> +QEMU. This provides a mechanism that works the same way regardless of 
> which
> +host OS you are running QEMU on. This section will describe this 
> second method
> +of using iSCSI together with QEMU.
> +
> +In QEMU, iSCSI devices are described using special iSCSI URLs
> +
> +@example
> +URL syntax:
> +iscsi://[<username>[%<password>]@@]<host>[:<port>]/<target-iqn-name>/<lun>
> +@end example
> +
> +Username and password are optional and only used if your taget is set up

taget -> target

> +using CHAP authentication for access control.
> +Alternatively the username and passwords can also be set via environment

password instead of passwords?

> +variables to have these not show up in the process list
> +
> +@example
> +export LIBISCSI_CHAP_USERNAME=<username>
> +export LIBISCSI_CHAP_PASSWORD=<password>
> +iscsi://<host>/<target-iqn-name>/<lun>
> +@end example
> +
> +Howto set up a simple iSCSI target on loopback and accessing it via QEMU:
> +@example
> +Setting up a iSCSI target with one CDROM and one DISK:
> +tgtd --iscsi portal=127.0.0.1:3260
> +tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.qemu.test
> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 \
> + -b /IMAGES/disk.img --device-type=disk
> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 \
> + -b /IMAGES/cd.iso --device-type=cd
> +tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
> +
> +qemu -boot d -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \

There is no qemu executable any longer. You may choose from
a large number of executable names, e.g. qemu-system-i386.

> + -cdrom iscsi://127.0.0.1/iqn.qemu.test/2
> +@end example
> +
> +
> +
> @node pcsys_network
> @section Network emulation

Thanks for providing this documentation.

Kind regards,

Stefan Weil

Re: [Qemu-devel] [PATCH] Documentation: Add section about iSCSI LUNS to qemu-doc

[Andreas Färber]

Hi,

Am 11.11.2011 22:46, schrieb Ronnie Sahlberg:
> Add a new section about using iSCSI LUNs with qemu
> and provide a short example on how to set up a target and access it
> using the built-in initiator
> 
> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
> ---
>  qemu-doc.texi |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 53 insertions(+), 0 deletions(-)
> 
> diff --git a/qemu-doc.texi b/qemu-doc.texi
> index 149e9bd..c1b293e 100644
> --- a/qemu-doc.texi
> +++ b/qemu-doc.texi

> +Howto set up a simple iSCSI target on loopback and accessing it via QEMU:
> +@example
> +Setting up a iSCSI target with one CDROM and one DISK:
> +tgtd --iscsi portal=127.0.0.1:3260
> +tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.qemu.test
> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 \
> +    -b /IMAGES/disk.img --device-type=disk
> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 \
> +    -b /IMAGES/cd.iso --device-type=cd
> +tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL

Having an example is always good.

These commands and parameters don't seem familiar to me, having worked
with iSCSI on Solaris, so this part of the example seems
platform-specific. Could you mention that this example is for Linux? Or
what specific upstream project these tools can be obtained from?

Please also remember to choose a subject, a recurring fault. ;)

Thanks,

Andreas

Re: [Qemu-devel] [PATCH] Documentation: Add section about iSCSI LUNS to qemu-doc

[ronnie sahlberg]

Hi,

On Sat, Nov 12, 2011 at 10:11 AM, Andreas Färber <andreas.faerber@web.de> wrote:
> Hi,
>
> Am 11.11.2011 22:46, schrieb Ronnie Sahlberg:
>> Add a new section about using iSCSI LUNs with qemu
>> and provide a short example on how to set up a target and access it
>> using the built-in initiator
>>
>> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
>> ---
>>  qemu-doc.texi |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 files changed, 53 insertions(+), 0 deletions(-)
>>
>> diff --git a/qemu-doc.texi b/qemu-doc.texi
>> index 149e9bd..c1b293e 100644
>> --- a/qemu-doc.texi
>> +++ b/qemu-doc.texi
>
>> +Howto set up a simple iSCSI target on loopback and accessing it via QEMU:
>> +@example
>> +Setting up a iSCSI target with one CDROM and one DISK:
>> +tgtd --iscsi portal=127.0.0.1:3260
>> +tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.qemu.test
>> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 \
>> +    -b /IMAGES/disk.img --device-type=disk
>> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 \
>> +    -b /IMAGES/cd.iso --device-type=cd
>> +tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
>
> Having an example is always good.
>
> These commands and parameters don't seem familiar to me, having worked
> with iSCSI on Solaris, so this part of the example seems
> platform-specific. Could you mention that this example is for Linux? Or
> what specific upstream project these tools can be obtained from?
>

I have mentioned now that this is Linux STGT target and that it comes
in the scsi-target-utils package.

Maybe add an example for Solaris too?
I don't use Solaris myself so I dont know how to configure iSCSI
target on Solaris.

Does OpenSolaris come with the same iSCSI target as Real-Solaris? If
so I could set it up in a VM and
try to figure out what a Solaris example could look like.


IMHO, examples are useful to get people up and running real quick to
get to a point where one they start experimenting.
straight away without having to search/learn lots of stuff first.



> Please also remember to choose a subject, a recurring fault. ;)

I know, I am completely hopless with 'git-send-email' :-)

regards
ronnie sahlberg

[Qemu-devel] Patch to add iSCSI documentation

[Ronnie Sahlberg]

List,

Please find an updated patch to add documentation for iSCSI and a simple
example how to set up a target to use with qemu.

It addresses the issues rised by the review of the first patch.

regards
ronnie sahlberg

[Qemu-devel] [PATCH] Documentation: Add section about iSCSI LUNS to qemu-doc

[Ronnie Sahlberg]

Add a new section about using iSCSI LUNs with qemu
and provide a short example on how to set up a target and access it
using the built-in initiator

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
---
 qemu-doc.texi |   56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 56 insertions(+), 0 deletions(-)

diff --git a/qemu-doc.texi b/qemu-doc.texi
index 149e9bd..1d37a91 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -421,6 +421,7 @@ snapshots.
 * disk_images_fat_images::    Virtual FAT disk images
 * disk_images_nbd::           NBD access
 * disk_images_sheepdog::      Sheepdog disk images
+* disk_images_iscsi::         iSCSI LUNs
 @end menu
 
 @node disk_images_quickstart
@@ -695,6 +696,61 @@ qemu-img create sheepdog:@var{hostname}:@var{port}:@var{image} @var{size}
 qemu sheepdog:@var{hostname}:@var{port}:@var{image}
 @end example
 
+@node disk_images_iscsi
+@subsection iSCSI LUNs
+
+iSCSI is a popular protocol used to access SCSI devices across a computer
+network. 
+
+There are two different ways iSCSI devices can be used by QEMU.
+
+The first method is to mount the iSCSI LUN on the host, and make it appear as
+any other ordinary SCSI device on the host and then to access this device as a
+/dev/sd device from QEMU. How to do this differs between host OSes.
+
+The second method involves using the iSCSI initiator that is built into
+QEMU. This provides a mechanism that works the same way regardless of which
+host OS you are running QEMU on. This section will describe this second method
+of using iSCSI together with QEMU.
+
+In QEMU, iSCSI devices are described using special iSCSI URLs
+
+@example
+URL syntax:
+iscsi://[<username>[%<password>]@@]<host>[:<port>]/<target-iqn-name>/<lun>
+@end example
+
+Username and password are optional and only used if your target is set up
+using CHAP authentication for access control.
+Alternatively the username and password can also be set via environment
+variables to have these not show up in the process list
+
+@example
+export LIBISCSI_CHAP_USERNAME=<username>
+export LIBISCSI_CHAP_PASSWORD=<password>
+iscsi://<host>/<target-iqn-name>/<lun>
+@end example
+
+Howto set up a simple iSCSI target on loopback and accessing it via QEMU:
+@example
+This example shows how to set up an iSCSI target with one CDROM and one DISK
+using the Linux STGT software target. This target is available on RedHat based
+systems as the package 'scsi-target-utils'.
+
+tgtd --iscsi portal=127.0.0.1:3260
+tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.qemu.test
+tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 \
+    -b /IMAGES/disk.img --device-type=disk
+tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 \
+    -b /IMAGES/cd.iso --device-type=cd
+tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
+
+qemu-system-i386 -boot d -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \
+    -cdrom iscsi://127.0.0.1/iqn.qemu.test/2
+@end example
+
+
+
 @node pcsys_network
 @section Network emulation
 
-- 
1.7.3.1

Re: [Qemu-devel] [PATCH] Documentation: Add section about iSCSI LUNS to qemu-doc

[Kevin Wolf]

Am 12.11.2011 01:06, schrieb Ronnie Sahlberg:
> Add a new section about using iSCSI LUNs with qemu
> and provide a short example on how to set up a target and access it
> using the built-in initiator
> 
> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>

Thanks, applied to the block-stable branch (for 1.0)

Kevin