Guest-agent on older linux servers?

[Hans Otto Lunde]

I've recently switched our relatively tiny virtual-infrastructure to Proxmox from Xen, and I'm so far REALLY pleased with it. I'm running 8 nodes in a cluster, and everything is running great.
However, I have a few older Linux-servers running Ubuntu 12.04 and Debian 6 (Squeeze) for various reasons.
On those it's not straight forward to get the qemu-guest-agent up and running.

On Ubuntu 12.04 there is a package that can just be installed, but the init-script throws an error saying:
"qemu-ga: transport endpoint not found, not starting..."

On Debian 6 there doesn't seem to be a package in the repos.

Before I start digging into this, maybe compiling stuff etc., I would like to hear from this forum if anybody could point me to some info on this issue.

Danish greetings
Hans Otto Lunde

 

[LnxBil]

"tiny virtual-infrastructure" with 8 nodes ... nice :-D

Unfortunately, I never found a solution that worked besides compiling the package for older versions. I tried once, but it was not that straight forward then, so I dropped it and started to migrate the VMs to a newer OS version or stuck to live without guest agent.

 

[Hans Otto Lunde]

"tiny virtual-infrastructure" with 8 nodes ... nice :-D

Unfortunately, I never found a solution that worked besides compiling the package for older versions. I tried once, but it was not that straight forward then, so I dropped it and started to migrate the VMs to a newer OS version or stuck to live without guest agent.

Thanks for your reply, LnxBil!
Well, maybe it's not worth the hassle to spend a lot of time on this. The VM's run just fine, and I can just close them manually if I need to do something that would require the agent to do something like that.
But it seems to me that the subject of the qemu-guest-agent is generally not documented very well. Or is it just me?

 

[wolfgang]

Hi
I think the problem is that your kernel do not support virtio devices.
So you can't use the vitrio-serial device as communication backend.

 

[LnxBil]

Thanks for your reply, LnxBil!
Well, maybe it's not worth the hassle to spend a lot of time on this. The VM's run just fine, and I can just close them manually if I need to do something that would require the agent to do something like that.
But it seems to me that the subject of the qemu-guest-agent is generally not documented very well. Or is it just me?

ACPI shutdown works, so the VM behaves normally. The only problem arises if you want to snapshot backup the VM, so that the outer backup cannot inform the guest that it is going to be backuped, so that it can prepare apps for backup (e.g. database log rotation, filesystem freeze etc).

 

[Hans Otto Lunde]

Again this is not a huge issue, but it would be nice to get it working.
On the two Debian 6 servers there are virtio kernel-modules as this listing shows:
.....
evdev 7352 0
i2c_core 15803 1 i2c_piix4
serio_raw 3752 0
pci_hotplug 21587 1 shpchp
container 2389 0
button 4650 0
virtio_balloon 2929 0
ext3 106502 1
jbd 37157 1 ext3
mbcache 5050 1 ext3
sg 24053 0
sr_mod 12602 0
cdrom 29351 1 sr_mod
ata_generic 3239 0
virtio_blk 4161 3
ata_piix 21108 0
virtio_net 10493 0
libata 133616 2 ata_generic,ata_piix
uhci_hcd 18473 0
ehci_hcd 31937 0
floppy 49167 0
thermal 11674 0
thermal_sys 11942 2 processor,thermal
scsi_mod 126677 3 sg,sr_mod,libata
virtio_pci 5495 0
virtio_ring 3242 1 virtio_pci
virtio 3277 4 virtio_balloon,virtio_blk,virtio_net,virtio_pci
usbcore 123175 4 usbhid,uhci_hcd,ehci_hcd
nls_base 6567 1 usbcore

but I still get the: "qemu-ga: transport endpoint not found, not starting ... (warning)."
On the Ubuntu 16.04 servers, where this works there is a /dev entry called "virtio-ports", but this is not present on the Debian-servers or the Ubuntu 12.04 ones. The communication with the guest-agent is over a socket, as I understand, so this might be the problem??

 

[wolfgang]

Please check is this kernel is build with needed flag.

/boot/config-* and checking for CONFIG_VIRTIO_CONSOLE=(y|m)

 

[Hans Otto Lunde]

the check says:

cat /boot/config-2.6.32-5-amd64 | grep VIRTIO
CONFIG_NET_9P_VIRTIO=m
CONFIG_VIRTIO_BLK=m
CONFIG_VIRTIO_NET=m
CONFIG_VIRTIO_CONSOLE=m
CONFIG_HW_RANDOM_VIRTIO=m
CONFIG_VIRTIO=m
CONFIG_VIRTIO_RING=m
CONFIG_VIRTIO_PCI=m
CONFIG_VIRTIO_BALLOON=m

but they are not all loaded, not CONFIG_VIRTIO_CONSOLE for example. But if I do a

insmod /lib/modules//2.6.32-5-amd64/kernel/drivers/char/virtio_console.ko

I get,

lsmod | grep virtio

virtio_console 2263 0 [permanent]
virtio_balloon 2929 0
virtio_blk 4161 3
virtio_net 10493 0
virtio_pci 5495 0
virtio_ring 3242 1 virtio_pci
virtio 3277 5 virtio_console,virtio_balloon,virtio_blk,virtio_net,virtio_pci

the module is loaded, but I still get a

/etc/init.d/qemu-guest-agent start
qemu-ga: transport endpoint not found, not starting ... (warning).

???

 

[wolfgang]

Have you set in the VM option the flag Qemu Agent?
If yes are the endpoints available?
May be the old qemu-guest-agent use the wrong path?

The correct endpoint path is
/dev/virtio-ports/org.qemu.guest_agent.0