hi, in the last 2 weeks we play a lot with our new server which we but to a our virtual server for the development and collect some very subjective experience. we use kvm and virt-manager, but sometimes i'm not really sure about the whether it's kvm or virt-manager problem so i collect them together. our system: MB: Intel S3000AHV CPU: Intel Core 2 Quad CPU Q6600 @ 2.40GHz RAM: 8GB CentOS 5 x86-64 host system with: kernel-2.6.18-8.1.8.el5 kmod-kvm-35-1.2.6.18_8.1.8.el5 kvm-35-1 libvirt-0.3.2-2 libvirt-python-0.3.2-2 python-virtinst-0.300.0-1 virt-manager-0.5.0-1 virt-top-0.3.2.5-1 virt-viewer-0.0.2-1
kvm is not ready for production use for many reason: it can't reboot which imho a very basic feature, what's more can't even shutdown/poweroff. the centos i386 guest are not able to shutdown on the x86_64 host (strange the x86_64 centos and the i586 mandrake-9 are able to shutdown) or what's seems to be more likely it's a random think.
can't give 2GB ram to any guests not even 2, but 1.9999 is ok. what's more i've to discover this in the hard way virt-manager gives some strange error message (anyway none of the virt-manager's error message are useful, just strange stack trace without any kind of useful info).
the host see as i've 4 cpu. i've got a change to gives more cpu to the guest, what's more they starts, but after a few minutes running the system crash. not just the guest os but the host os crash without any kind of info, log or any useful info what was the cause of it, but hard reset helps:-((( first of all it's serious problem, even if it's a known bug and documented somewhere (but there is not any kind of docs about neither kvm nor virt-manager/libvirt and what i can find that very limited), since all of the new hvm cpu (which is required for kvm) has more core, so the guest can't use the real power of the cpu this means i've to put a lots of guests with one virtual cpu to the host or currently can't exploit these cpus.
libvirt not start the guest when the host started, not saved the state of the guests when stopped, when restarted all guest get into shutdown state. may be it's just libvirt but, but if kvm not able to save it's guest's state that it's a real pain. this behavior not acceptable in a real environment.
in virt-manager can't modify virtual cpu number of the guests (virt-manager crash with another unusable stacks trace). it i modify the xml config file by hand i've to restart libvirt in order to read it. even if i just modify one guest's config, but as if i restart libvirtd the all other guest will be killed it's another nice feature.
from vit-manager i can't assign swap partitions (and any other device to the guests) during guest creation. i precreate lvm partition on the host for root and swap to all of our guests (about 10) but it's a real pain to reload libvirtd (which kills all guests) to add a new disk to the guest which can be used as a swap or other partition. what's more it'd be useful to add swap partition during install. the same thing apply to cdrom too.
if i made a mistake in the libvirtd xml config file, then i don't get any kind of error message just libvirt don't start the given guest. no error message service seems to start without error and don't know what was the reason that the guest not start (sometimes because syntactic error in the config file, sometimes kvm/qemu not support it eg more then 2gb mem). there are unwritten unix/linux tradition eg if there are error during a service startup report it some log file. if a service can't start without error then it not start at all eg. if i've apache with 5 virtual host but one of it's config has error then the whole httpd not started. it'd have to be the same with libvirt too.
libvirt config file has all the features as qemu command line (if not it can't be used by advanced users)? but i don't know since there is not a reference docs for the config file.
there is not a detailed reference docs about libvirtd config (and at the same time the gui not contains all the settings). for the the xml format is a bit redundant eg. "source dev", "target dev" why not just source and target, inside interface type='bridge' 'source bridge' why not just source (i've to modify two place when i'd like to switch from network to bride. ok these are just small cosmetic thing just mention.
when create a new guest in virt-manager and reach the last page and press finish then most of the time (2 times from 3) i've got an error something like "can't connect to qemu" after i press ok and press again finish then it's able to create the new host (so always have to retry it).
in virt-manager when a guest is shutdown and double-click on the guest and try to start it it's not possible. you've to select the guest in the main windows, right-click and start it.
the new vnc based console is very unstable or just virt-manager not able to connect it. many times i double click on a guest in virt-manager i got the window can't connect to console while the guest are running. that's why i like to see again the serial console.
we've got other virtual servers with xen and openvz, with has other problems but works. my conclusion is that currently kvm, libvirtd, virt-manager (et-mgmt-tools) seems very promising. but currently just in a very alpha stage using even in non mission critical but production environment still a very 'brave' decision. xen has a few years vantage, but it's at least usable in real environment. i'm on the these list and see what kind of problem you're working which is great but at the same it'd be useful to fix the most basic problems with these tools.
just my 2c to these community.
Farkas Levente wrote:
hi, in the last 2 weeks we play a lot with our new server which we but to a our virtual server for the development and collect some very subjective experience. we use kvm and virt-manager, but sometimes i'm not really sure about the whether it's kvm or virt-manager problem so i collect them together. our system:
thansk!
MB: Intel S3000AHV CPU: Intel Core 2 Quad CPU Q6600 @ 2.40GHz RAM: 8GB CentOS 5 x86-64 host system with: kernel-2.6.18-8.1.8.el5 kmod-kvm-35-1.2.6.18_8.1.8.el5 kvm-35-1 libvirt-0.3.2-2 libvirt-python-0.3.2-2 python-virtinst-0.300.0-1 virt-manager-0.5.0-1 virt-top-0.3.2.5-1 virt-viewer-0.0.2-1
kvm is not ready for production use for many reason: it can't reboot which imho a very basic feature, what's more can't even shutdown/poweroff. the centos i386 guest are not able to shutdown on the x86_64 host (strange the x86_64 centos and the i586 mandrake-9 are able to shutdown) or what's seems to be more likely it's a random think.
this issue is known and will be fix soon.
can't give 2GB ram to any guests not even 2, but 1.9999 is ok. what's more i've to discover this in the hard way virt-manager gives some strange error message (anyway none of the virt-manager's error message are useful, just strange stack trace without any kind of useful info).
kvm from version 36 support above 2giga of ram (it was tested with 32giga ram guest)
the host see as i've 4 cpu. i've got a change to gives more cpu to the guest, what's more they starts, but after a few minutes running the system crash. not just the guest os but the host os crash without any kind of info, log or any useful info what was the cause of it, but hard reset helps:-((( first of all it's serious problem, even if it's a known bug and documented somewhere (but there is not any kind of docs about neither kvm nor virt-manager/libvirt and what i can find that very limited), since all of the new hvm cpu (which is required for kvm) has more core, so the guest can't use the real power of the cpu this means i've to put a lots of guests with one virtual cpu to the host or currently can't exploit these cpus.
libvirt not start the guest when the host started, not saved the state of the guests when stopped, when restarted all guest get into shutdown state. may be it's just libvirt but, but if kvm not able to save it's guest's state that it's a real pain. this behavior not acceptable in a real environment.
in virt-manager can't modify virtual cpu number of the guests (virt-manager crash with another unusable stacks trace). it i modify the xml config file by hand i've to restart libvirt in order to read it. even if i just modify one guest's config, but as if i restart libvirtd the all other guest will be killed it's another nice feature.
from vit-manager i can't assign swap partitions (and any other device to the guests) during guest creation. i precreate lvm partition on the host for root and swap to all of our guests (about 10) but it's a real pain to reload libvirtd (which kills all guests) to add a new disk to the guest which can be used as a swap or other partition. what's more it'd be useful to add swap partition during install. the same thing apply to cdrom too.
if i made a mistake in the libvirtd xml config file, then i don't get any kind of error message just libvirt don't start the given guest. no error message service seems to start without error and don't know what was the reason that the guest not start (sometimes because syntactic error in the config file, sometimes kvm/qemu not support it eg more then 2gb mem). there are unwritten unix/linux tradition eg if there are error during a service startup report it some log file. if a service can't start without error then it not start at all eg. if i've apache with 5 virtual host but one of it's config has error then the whole httpd not started. it'd have to be the same with libvirt too.
libvirt config file has all the features as qemu command line (if not it can't be used by advanced users)? but i don't know since there is not a reference docs for the config file.
there is not a detailed reference docs about libvirtd config (and at the same time the gui not contains all the settings). for the the xml format is a bit redundant eg. "source dev", "target dev" why not just source and target, inside interface type='bridge' 'source bridge' why not just source (i've to modify two place when i'd like to switch from network to bride. ok these are just small cosmetic thing just mention.
when create a new guest in virt-manager and reach the last page and press finish then most of the time (2 times from 3) i've got an error something like "can't connect to qemu" after i press ok and press again finish then it's able to create the new host (so always have to retry it).
in virt-manager when a guest is shutdown and double-click on the guest and try to start it it's not possible. you've to select the guest in the main windows, right-click and start it.
the new vnc based console is very unstable or just virt-manager not able to connect it. many times i double click on a guest in virt-manager i got the window can't connect to console while the guest are running. that's why i like to see again the serial console.
we've got other virtual servers with xen and openvz, with has other problems but works. my conclusion is that currently kvm, libvirtd, virt-manager (et-mgmt-tools) seems very promising. but currently just in a very alpha stage using even in non mission critical but production environment still a very 'brave' decision. xen has a few years vantage, but it's at least usable in real environment. i'm on the these list and see what kind of problem you're working which is great but at the same it'd be useful to fix the most basic problems with these tools.
just my 2c to these community.
thanks for all this information, this exactly what we need!
From: "Farkas Levente" lfarkas@bppiac.hu
RAM: 8GB CentOS 5 x86-64 host system with: can't give 2GB ram to any guests not even 2, but 1.9999 is ok. what's
So far as i know u need to use a PAE kernel to use >2Gb.
Danny.
D.Terweij | NTG-Support wrote:
From: "Farkas Levente" lfarkas@bppiac.hu
RAM: 8GB CentOS 5 x86-64 host system with: can't give 2GB ram to any guests not even 2, but 1.9999 is ok. what's
So far as i know u need to use a PAE kernel to use >2Gb.
not on x86_64 and just over 4gb on i386.
On 9/8/07, Farkas Levente lfarkas@bppiac.hu wrote:
kvm is not ready for production use for many reason: it can't reboot which imho a very basic feature, what's more can't even shutdown/poweroff. the centos i386 guest are not able to shutdown on the x86_64 host (strange the x86_64 centos and the i586 mandrake-9 are able to shutdown) or what's seems to be more likely it's a random think.
Reboot failure is a regression; for shutdown you should enable APCI with "acpi=force"; bochs BIOS doesn't have SMBIOS/DMI tables and Linux may refuse to use ACPI without them (it depends on the configuration).
Luca
Luca wrote:
On 9/8/07, Farkas Levente lfarkas@bppiac.hu wrote:
kvm is not ready for production use for many reason: it can't reboot which imho a very basic feature, what's more can't even shutdown/poweroff. the centos i386 guest are not able to shutdown on the x86_64 host (strange the x86_64 centos and the i586 mandrake-9 are able to shutdown) or what's seems to be more likely it's a random think.
Reboot failure is a regression; for shutdown you should enable APCI with "acpi=force"; bochs BIOS doesn't have SMBIOS/DMI tables and Linux may refuse to use ACPI without them (it depends on the configuration).
when, where, how? is there any docs about it?
On Sat, 2007-09-08 at 13:15 +0200, Farkas Levente wrote:
hi, kvm is not ready for production use for many reason: it can't reboot which imho a very basic feature, what's more can't even shutdown/poweroff. the centos i386 guest are not able to shutdown on the x86_64 host (strange the x86_64 centos and the i586 mandrake-9 are able to shutdown) or what's seems to be more likely it's a random think.
can't give 2GB ram to any guests not even 2, but 1.9999 is ok. what's more i've to discover this in the hard way virt-manager gives some strange error message (anyway none of the virt-manager's error message are useful, just strange stack trace without any kind of useful info).
kvm-36 now supports more than 2GB of RAM per guest. You're one version off for that.
the host see as i've 4 cpu. i've got a change to gives more cpu to the guest, what's more they starts, but after a few minutes running the system crash. not just the guest os but the host os crash without any kind of info, log or any useful info what was the cause of it, but hard reset helps:-((( first of all it's serious problem, even if it's a known bug and documented somewhere (but there is not any kind of docs about neither kvm nor virt-manager/libvirt and what i can find that very limited), since all of the new hvm cpu (which is required for kvm) has more core, so the guest can't use the real power of the cpu this means i've to put a lots of guests with one virtual cpu to the host or currently can't exploit these cpus.
I'm having difficulty understanding what your problem is. Are you saying that guest SMP isn't working for you? The host OS definitely shouldn't crash. Can you be more specific about what configs you are using? There was a host oops fixed in kvm-36 so upgrading may help you.
Regards,
Anthony Liguori
libvirt not start the guest when the host started, not saved the state of the guests when stopped, when restarted all guest get into shutdown state. may be it's just libvirt but, but if kvm not able to save it's guest's state that it's a real pain. this behavior not acceptable in a real environment.
in virt-manager can't modify virtual cpu number of the guests (virt-manager crash with another unusable stacks trace). it i modify the xml config file by hand i've to restart libvirt in order to read it. even if i just modify one guest's config, but as if i restart libvirtd the all other guest will be killed it's another nice feature.
from vit-manager i can't assign swap partitions (and any other device to the guests) during guest creation. i precreate lvm partition on the host for root and swap to all of our guests (about 10) but it's a real pain to reload libvirtd (which kills all guests) to add a new disk to the guest which can be used as a swap or other partition. what's more it'd be useful to add swap partition during install. the same thing apply to cdrom too.
if i made a mistake in the libvirtd xml config file, then i don't get any kind of error message just libvirt don't start the given guest. no error message service seems to start without error and don't know what was the reason that the guest not start (sometimes because syntactic error in the config file, sometimes kvm/qemu not support it eg more then 2gb mem). there are unwritten unix/linux tradition eg if there are error during a service startup report it some log file. if a service can't start without error then it not start at all eg. if i've apache with 5 virtual host but one of it's config has error then the whole httpd not started. it'd have to be the same with libvirt too.
libvirt config file has all the features as qemu command line (if not it can't be used by advanced users)? but i don't know since there is not a reference docs for the config file.
there is not a detailed reference docs about libvirtd config (and at the same time the gui not contains all the settings). for the the xml format is a bit redundant eg. "source dev", "target dev" why not just source and target, inside interface type='bridge' 'source bridge' why not just source (i've to modify two place when i'd like to switch from network to bride. ok these are just small cosmetic thing just mention.
when create a new guest in virt-manager and reach the last page and press finish then most of the time (2 times from 3) i've got an error something like "can't connect to qemu" after i press ok and press again finish then it's able to create the new host (so always have to retry it).
in virt-manager when a guest is shutdown and double-click on the guest and try to start it it's not possible. you've to select the guest in the main windows, right-click and start it.
the new vnc based console is very unstable or just virt-manager not able to connect it. many times i double click on a guest in virt-manager i got the window can't connect to console while the guest are running. that's why i like to see again the serial console.
we've got other virtual servers with xen and openvz, with has other problems but works. my conclusion is that currently kvm, libvirtd, virt-manager (et-mgmt-tools) seems very promising. but currently just in a very alpha stage using even in non mission critical but production environment still a very 'brave' decision. xen has a few years vantage, but it's at least usable in real environment. i'm on the these list and see what kind of problem you're working which is great but at the same it'd be useful to fix the most basic problems with these tools.
just my 2c to these community.
On 9/8/07, Anthony Liguori anthony@codemonkey.ws wrote:
I'm having difficulty understanding what your problem is. Are you saying that guest SMP isn't working for you? The host OS definitely shouldn't crash. Can you be more specific about what configs you are using? There was a host oops fixed in kvm-36 so upgrading may help you.
I have not spent enough time on kvm, so cannot make any technically useful comment. It's just observations. This is with kvm-35; when the guest crashes, it takes the whole system down. The only way out it to reboot. Again no analysis done yet. But if kvm-36 addresses a host oops, I should try that.
Daniel, any chance you can make the -36 available in c5-testing?
Akemi
Anthony Liguori wrote:
the host see as i've 4 cpu. i've got a change to gives more cpu to the guest, what's more they starts, but after a few minutes running the system crash. not just the guest os but the host os crash without any kind of info, log or any useful info what was the cause of it, but hard reset helps:-((( first of all it's serious problem, even if it's a known bug and documented somewhere (but there is not any kind of docs about neither kvm nor virt-manager/libvirt and what i can find that very limited), since all of the new hvm cpu (which is required for kvm) has more core, so the guest can't use the real power of the cpu this means i've to put a lots of guests with one virtual cpu to the host or currently can't exploit these cpus.
I'm having difficulty understanding what your problem is. Are you
after i reread my sentences it was difficult for me too:-(
saying that guest SMP isn't working for you? The host OS definitely shouldn't crash. Can you be more specific about what configs you are using? There was a host oops fixed in kvm-36 so upgrading may help you.
exactly. i've got 4 phisical core (Intel Core 2 Quad) and i try to give 4 cpus for 2 guests and 2 cpus for a third guest and restart libvirtd. the result was that even the host system crash without any stack trace or kernel panic and only the hard reset helps.
-
Akemi Yagi -
Anthony Liguori -
D.Terweij | NTG-Support -
Daniel de Kok -
Farkas Levente -
Izik Eidus -
Luca