[libvirt] listing domains on Fedora 8 XEN kernel

[Steve Oliphant]

I have answered my own question.

On an XEN kernel, the default hypervisor is XEN and I did not have any
XEN domains.

If I explicitly connect to QEMU - my programs work fine.

I discovered this fact by running the existing programs with
the connect string:

"qemu://steve-1.verizon.net/system"

I then created an XEN domain and when I reconnected with

 "xen://steve-1.verizon.net/system"

I received the XEN domain information.

I know this bit of information is very familiar to those who
are experienced in the world of virtual machines.  I am passing
the information on for those who are new to this environment.

Thanks

Steve

Date sent:      	Mon, 14 Jul 2008 12:56:24 -0400
From:           	Steve Oliphant <sdoliphant at verizon.net>
Subject:        	[libvirt] listing domains on Fedora 8 XEN kernel
To:             	libvir-list at redhat.com
Send reply to:  	n2kbd at arrl.net

> I am having a problem being able to get domain information in an Fedora
> 8 XEN environment.The code does not receive an error status on the XEN
> kernel and does not get any information.
> 
> The same code running on the non XEN kernel works fine.
> 
> I am running default configuration files.  
> 
> Is this a known issue?
> Do I need to tweak the configuration files?
> 
> Is there anything else I need to do get the code to work on the XEN
> kernel?  Please point me in the right direction.
> 
> If any other information is required to assist in answering my question,
> please let me know.
> 
> Thank you in advance for your help.
> 
> Steven Oliphant
> 
> Software installed:
> 
> rpm -qa | grep kernel 
> 
> kernel-headers-2.6.25.9-40.fc8
> kernel-devel-2.6.23.1-42.fc8
> kernel-2.6.23.1-42.fc8
> kernel-xen-2.6.21-2950.fc8
> kernel-2.6.25.9-40.fc8
> kernel-devel-2.6.25.9-40.fc8
> kernel-xen-2.6.21.7-3.fc8
> 
> rpm -qa | grep xen
> 
> xen-devel-3.1.2-2.fc8
> xenwatch-0.5.2-2.fc8
> kernel-xen-2.6.21-2950.fc8
> xen-debuginfo-3.1.2-2.fc8
> kernel-xen-2.6.21.7-3.fc8
> xen-libs-3.1.2-2.fc8
> xen-3.1.2-2.fc8
> 
> rpm -qa | grep virt
> 
> libvirt-devel-0.4.4-1.fc8
> ruby-libvirt-0.0.7-1.fc8
> libvirt-python-0.4.4-1.fc8
> python-virtinst-0.300.2-4.fc8
> virt-manager-0.5.3-2.fc8
> libvirt-debuginfo-0.4.4-1.fc8
> libvirt-0.4.4-1.fc8
> 
> Non XEN kernel:
> 
> uname -a
> Linux steve-1.verizon.net 2.6.25.9-40.fc8 #1 SMP Fri Jun 27 16:25:53 EDT
> 2008 i686 athlon i386 GNU/Linux
> 
> XEN kernel
> 
> uname -a
> Linux steve-1.verizon.net 2.6.21.7-3.fc8xen #1 SMP Thu Mar 20 14:57:53
> EDT 2008 i686 athlon i386 GNU/Linux
> 
> Code sample:
> 
> #include <stdio.h>
> #include <libvirt/libvirt.h>
> 
> #define DOMAIN_COUNT   10
> 
> /**
>  * getInfo:
>  *
>  * extract the virtual machine information
>  */
> static void
> getInfo(void) {
>     virConnectPtr conn = NULL; /* the hypervisor connection */
>     virDomainPtr dom = NULL;   /* the domain being checked */
> 
>     int ret;
>     int id;
>     int i, j, k, ids[DOMAIN_COUNT];
>     
>     char *names[DOMAIN_COUNT];
> 
>     /* NULL means connect to local Xen hypervisor */
>     
>     conn = virConnectOpen(NULL);
>     if (conn == NULL) {
>       fprintf(stderr, "Failed to connect to hypervisor\n");
>       goto error;
>     }
> 
>     /* Get the active domain list */
> 	  
>     i = virConnectListDomains(conn, &ids[0], DOMAIN_COUNT);
> 	  if (i < 0) {
> 	    fprintf(stderr, "Failed to list the domains\n");
> 	    goto error;
> 	  }
> 	  for (j = 0;j < i;j++) {
> 	    if (ids[j] != 0) {
> 	      id = ids[j];
> 		    fprintf(stdout, "Active Domain: %d\n", id);
>         /* Get the information */
> 
> 	    }
> 
>     }
>     /* Get defined Domain Names */
> 
>     ret = virConnectListDefinedDomains (conn, names, DOMAIN_COUNT);
>     if (ret < 0) {
>       fprintf(stderr, "Failed to get Domain Names\n");
> 	    goto error;
>     }
> 
>     for (k = 0;k < ret;k++) {
>       printf("Inactive Domain Name: %s\n", names[k]);
>     }
> 
> 
> error:
>     if (dom != NULL)
>       virDomainFree(dom);
>     if (conn != NULL)
>       virConnectClose(conn);
> }
> 
> int main() {
> 
>     getInfo();
> 
>     return(0);
> }
> 
> 
> --
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Steve Oliphant - N2KBD
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