Re: [libvirt-users] Detach disk from VM - virsh (working) vs. PHP (not working)
On 8/1/19 10:12 AM, Jan Horak wrote:
Hi all,
i created a script in PHP for create a virtual server with two QCOW2 discs … one is our
system for installation and second is target system.
After successfully instalation (create a blank Debian system, prepare all files and grub
partitions) i need a restart virtual without a installation disk.
If i use Virsh:
detach-disk --domain debian-test2 --persistent --target vda
reset debian-test2
everything works well.
If i use a PHP, there is „complicated“ way and „simple“ way:
1, complicated:
libvirt_domain_destroy($domain);
libvirt_domain_undefine($domain);
$xml = domain_create_xml($name,$uuid,$memory,$cpu,$vnc,$mac);
$domain = libvirt_domain_define_xml($server->conn, $xml);
libvirt_domain_disk_add($domain, "/users/".$name.".img",
"vdb", "virtio", "qcow2", NULL);
libvirt_domain_create($domain);
(or instead libvirt_domain_disk_add i can define disk directly in XML)
But in this case, the server will not boot (GRUB error)
Question is, how GRUB refers to the disk where kernel is to be found.
Also, I suspect it is not GRUB that is complaining, but SeaBIOS which
hasn't found any bootable device. It's only an assumption becasue I
don't know how domain_create_xml() works - it's not a libvirt-php
function. There are two possibilities here:
1) make sure domain_create_xml() sets boot devices
2) construct disk XML yourself, and put "<boot order='N'/>" into
it
2, simple:
libvirt_domain_disk_remove($domain,“vda“);
libvirt_domain_reboot($domain);
The problem of this solution is thats not working. The remove disk is failing with error
„Unable attach disk“ - i looks to source code, and yes, there is a mystake with
„attach“/„detach“, but main problem i see in log from libvirt:
Oh, that's only typo in the error message. In fact the detach API is
called. And it fails.
Aug 1 02:57:05 ry libvirtd[19051]: missing source information for device vda
I try to put source detail to xml in source of PHP module
libvirt-domain.c:
822 if (asprintf(&newXml,
823 " <disk type='file'
device='disk'>\n"
824 " <target dev='%s'/>\n"
825 " </disk>", dev) < 0) {
826 set_error("Out of memory" TSRMLS_CC);
827 goto error;
828 }
but my attempts was unsuccesfull (i’m not C programmer).
Yes, this minimalistic XML is not good as detach API requires full
device XML. I'll fix this soon.
Questions:
A, why complicated way is not working and system dont want boot (GRUB error) if virsh
works fine
B, why libvirt_domain_disk_remove is not work ? I use libvirt and libvirt-php latest from
git.
I've pushed fixes here:
Please give it a try.
Michal