<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Thank you, Rich,<div>This was the issue indeed. <font face="monospace, monospace">export LIBGUESTFS_BACKEND=direct </font>fixed it.<div><br></div><div>The next step I tried was to integrate libguestfs in collectd virt plugin to collect this data automatically.</div><div>In this case I'm having an unknown error in <font face="monospace, monospace">add_libvirt_dom()</font> (same with <font face="monospace, monospace">add_domain</font>) when it's invoking <font face="monospace, monospace">qemu-img</font> to create overlay image.</div><div><br></div><div>There is no difference between manual and service execution.</div><div>I tried setting LIBGUESTFS_BACKEND to direct, libvirt, libvirt:qemu:///session with no success.</div><div>Also tried using a different tmp dir just in case - nothing.</div><div><br></div><div>Maybe something is wrong with how collectd runs its plugins (dynamic linking)?</div><div>Invoking virt-df from collectd's plugin gives the same error message.</div><div>I tried running the same qemu-img command from collectd and it passes though! Confusing...</div><div><br></div><div>Do you have any hints what to try?</div><div><br></div><div>Here is the complete output from collectd:</div></div></div></div></div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div><div><div><div><div><div>[<font face="monospace, monospace">2018-11-07 12:21:54] plugin_load: plugin "logfile" successfully loaded.</font></div></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">[2018-11-07 12:21:54] plugin_load: plugin "syslog" successfully loaded.</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">Before guestfs_create()</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">UID: 0</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">Effective UID: 0</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">Before guestfs_set_verbose()</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">Before guestfs_set_trace()</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">Before guestfs_add_domain()</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: add_domain "wer" "readonly:true"</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: opening libvirt handle: URI = NULL, auth = default+wrapper, flags = 0</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: successfully opened libvirt handle: conn = 0x7f7e70005210</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: add_libvirt_dom (virDomainPtr)0x7f7e70005fa0 "readonly:true"</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: original domain XML:\n<domain type='kvm' id='9'>\n <name>wer</name>\n <uuid>03fde334-92a5-4e5e-9247-924c9d40230f</uuid>\n <memory unit='KiB'>2097152</memory>\n <currentMemory unit='KiB'>2097152</currentMemory>\n <vcpu placement='static'>1</vcpu>\n <resource>\n <partition>/machine</partition>\n </resource>\n <os>\n <type arch='x86_64' machine='pc-i440fx-2.7'>hvm</type>\n <bootmenu enable='yes'/>\n </os>\n <features>\n <acpi/>\n <apic/>\n <vmport state='off'/>\n </features>\n <cpu mode='custom' match='exact'>\n <model fallback='allow'>Westmere</model>\n </cpu>\n <clock offset='utc'>\n <timer name='rtc' tickpolicy='catchup'/>\n <timer name='pit' tickpolicy='delay'/>\n <timer name='hpet' present='no'/>\n </clock>\n <on_poweroff>destroy</on_poweroff>\n <on_reboot>restart</on_reboot>\n <on_crash>destroy</on_crash>\n <pm>\n <suspend-to-mem enabled='no'/>\n <suspend-to-disk enabled='no'/>\n </pm>\n <devices>\n <emulator>/usr/bin/qemu-kvm</emulator>\n <disk type='file' device='disk'>\n <driver name='qemu' type='qcow2'/>\n <source file='/home/peterd/TVE/wer.qcow2'/>\n <backingStore/>\n <target dev='sda' bus='sata'/>\n <boot order='1'/>\n <alias name='sata0-0-0'/>\n <address type='drive' controller='0' bus='0' target='0' unit='0'/>\n </disk>\n <disk type='file' device='disk'>\n <driver name='qemu' type='qcow2'/>\n <source file='/var/lib/libvirt/images/wer.qcow2'/>\n <backingStore/>\n <target dev='sdb' bus='sata'/>\n <alias name='sata0-0-1'/>\n <address type='drive' controller='0' bus='0' target='0' unit='1'/>\n </disk>\n <disk type='file' device='cdrom'>\n <driver name='qemu' type='raw'/>\n <source file='/home/peterd/boot_new.iso'/>\n <backingStore/>\n <target dev='hda' bus='ide'/>\n <readonly/>\n <boot order='2'/>\n <alias name='ide0-0-0'/>\n <address type='drive' controller='0' bus='0' target='0' unit='0'/>\n </disk>\n <controller type='usb' index='0' model='ich9-ehci1'>\n <alias name='usb'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x7'/>\n </controller>\n <controller type='usb' index='0' model='ich9-uhci1'>\n <alias name='usb'/>\n <master startport='0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0' multifunction='on'/>\n </controller>\n <controller type='usb' index='0' model='ich9-uhci2'>\n <alias name='usb'/>\n <master startport='2'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x1'/>\n </controller>\n <controller type='usb' index='0' model='ich9-uhci3'>\n <alias name='usb'/>\n <master startport='4'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x2'/>\n </controller>\n <controller type='ide' index='0'>\n <alias name='ide'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>\n </controller>\n <controller type='sata' index='0'>\n <alias name='sata0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>\n </controller>\n <controller type='virtio-serial' index='0'>\n <alias name='virtio-serial0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>\n </controller>\n <controller type='scsi' index='0' model='virtio-scsi'>\n <alias name='scsi0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>\n </controller>\n <controller type='pci' index='0' model='pci-root'>\n <alias name='pci.0'/>\n </controller>\n <interface type='direct'>\n <mac address='52:54:00:2c:7a:bf'/>\n <source dev='macvlan0' mode='bridge'/>\n <target dev='macvtap0'/>\n <model type='e1000'/>\n <alias name='net0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>\n </interface>\n <serial type='pty'>\n <source path='/dev/pts/8'/>\n <target port='0'/>\n <alias name='serial0'/>\n </serial>\n <console type='pty' tty='/dev/pts/8'>\n <source path='/dev/pts/8'/>\n <target type='serial' port='0'/>\n <alias name='serial0'/>\n </console>\n <channel type='spicevmc'>\n <target type='virtio' name='com.redhat.spice.0' state='disconnected'/>\n <alias name='channel0'/>\n <address type='virtio-serial' controller='0' bus='0' port='1'/>\n </channel>\n <input type='mouse' bus='ps2'>\n <alias name='input0'/>\n </input>\n <input type='keyboard' bus='ps2'>\n <alias name='input1'/>\n </input>\n <graphics type='spice' port='5900' autoport='yes' listen='127.0.0.1'>\n <listen type='address' address='127.0.0.1'/>\n <image compression='off'/>\n </graphics>\n <sound model='ich6'>\n <alias name='sound0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>\n </sound>\n <video>\n <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>\n <alias name='video0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>\n </video>\n <redirdev bus='usb' type='spicevmc'>\n <alias name='redir0'/>\n <address type='usb' bus='0' port='1'/>\n </redirdev>\n <redirdev bus='usb' type='spicevmc'>\n <alias name='redir1'/>\n <address type='usb' bus='0' port='2'/>\n </redirdev>\n <memballoon model='virtio'>\n <alias name='balloon0'/>\n <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>\n </memballoon>\n </devices>\n <seclabel type='none' model='none'/>\n <seclabel type='dynamic' model='dac' relabel='yes'>\n <label>+0:+0</label>\n <imagelabel>+0:+0</imagelabel>\n </seclabel>\n</domain>\n</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: clear_backend_setting "internal_libvirt_norelabel_disks"</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: clear_backend_setting = 0</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: disk[0]: filename: /home/peterd/TVE/wer.qcow2</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: add_drive "/home/peterd/TVE/wer.qcow2" "readonly:true" "format:qcow2"</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: creating COW overlay to protect original drive content</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: get_tmpdir</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: get_tmpdir = "/tmp"</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: disk_create "/tmp/libguestfsUIZbDK/overlay1.qcow2" "qcow2" -1 "backingfile:/home/peterd/TVE/wer.qcow2" "backingformat:qcow2"</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: command: run: qemu-img</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: command: run: \ create</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: command: run: \ -f qcow2</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: command: run: \ -o backing_file=/home/peterd/TVE/wer.qcow2,backing_fmt=qcow2</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: command: run: \ /tmp/libguestfsUIZbDK/overlay1.qcow2</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">Formatting '/tmp/libguestfsUIZbDK/overlay1.qcow2', fmt=qcow2 size=107374182400 backing_file=/home/peterd/TVE/wer.qcow2 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: error: command: waitpid: No child processes</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: error: qemu-img: /tmp/libguestfsUIZbDK/overlay1.qcow2: qemu-img exited for an unknown reason (status -1), see debug messages above</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: disk_create = -1 (error)</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: add_drive = -1 (error)</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: add_libvirt_dom = -1 (error)</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: add_domain = -1 (error)</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: trace: close</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: closing guestfs handle 0x7f7e700049f0 (state 0)</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: command: run: rm</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: command: run: \ -rf /tmp/libguestfsUIZbDK</font></div></div></div></div></div><div><div><div><div><div><font face="monospace, monospace">libguestfs: error: command: waitpid: No child processes</font></div></div></div></div></div></blockquote><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><br></div><div><br clear="all"><div><div dir="ltr" class="gmail_signature"><div dir="ltr">Best Regards,<br>Peter</div></div></div><br></div></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Fri, Nov 2, 2018 at 9:48 PM Richard W.M. Jones <<a href="mailto:rjones@redhat.com">rjones@redhat.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Fri, Nov 02, 2018 at 06:04:08PM +0200, Peter Dimitrov wrote:<br>
> Hello,<br>
> <br>
> I have a simple C program that uses libguestfs to extract info about disk<br>
> usage from a libvirt domain. It works when ran manually as root, but fails<br>
> when started as a systemd service.<br>
> <br>
> I'm attaching the service file, source code and verbose logs from both the<br>
> successful manual run and from the service journal.<br>
> <br>
> SELinix is disabled.<br>
> <br>
> Error messages:<br>
> libguestfs: set_socket_create_context: getcon failed: (none): Invalid<br>
> argument [you can ignore this message if you are not using SELinux + sVirt]<br>
> libguestfs: clear_socket_create_context: setsockcreatecon failed: NULL:<br>
> Invalid argument [you can ignore this message if you are not using SELinux<br>
> + sVirt]<br>
> libguestfs: error: chown: /tmp/libguestfsvMMaec/guestfsd.sock: Operation<br>
> not permitted<br>
> libguestfs: clear_socket_create_context: setsockcreatecon failed: NULL:<br>
> Invalid argument [you can ignore this message if you are not using SELinux<br>
> + sVirt]<br>
> libguestfs: trace: launch = -1 (error)<br>
> failed to launch domain: Invalid argument<br>
<br>
I cannot see what the problem is immediately, but I guess that systemd<br>
is confining the service in such a way that libvirt has problems.<br>
<br>
Firstly I would try using the direct backend:<br>
<br>
export LIBGUESTFS_BACKEND=direct<br>
<br>
If it's still not fixed, then it's something to do with systemd<br>
confining affecting qemu.<br>
<br>
If that fixes it, then it's a problem with libvirt, and you will need<br>
to find the libvirt log file. Usually that's in<br>
/var/log/libvirt/qemu/guestfs-*.log or in<br>
$HOME/.cache/libvirt/qemu/log/guestfs-*.log But I've no idea where it<br>
will end up when you're running everything under systemd.<br>
<br>
Rich.<br>
<br>
-- <br>
Richard Jones, Virtualization Group, Red Hat <a href="http://people.redhat.com/~rjones" rel="noreferrer" target="_blank">http://people.redhat.com/~rjones</a><br>
Read my programming and virtualization blog: <a href="http://rwmj.wordpress.com" rel="noreferrer" target="_blank">http://rwmj.wordpress.com</a><br>
virt-p2v converts physical machines to virtual machines. Boot with a<br>
live CD or over the network (PXE) and turn machines into KVM guests.<br>
<a href="http://libguestfs.org/virt-v2v" rel="noreferrer" target="_blank">http://libguestfs.org/virt-v2v</a><br>
</blockquote></div>