Dear Friends, Thanks for your suggestions. I have implemented them; all works! Now the security module at the hypervisor (KVM) analyzed the data coming from guest and decided that this guest malfunctions and must be rebooted. When rebooting I address the VM being rebooted by its name: first getting the domain by name (virDomainLookupByName) and then reboot the domain (virDomainReset). The problem is: how can I get the VM name, having the malfunctioning VCPU (struct kvm_vcpu) as the context ? I retrieve VCPUs using the following loop: raw_spin_lock(vm_lock); list_for_each_entry(kvm, vms_list, vm_list) { for (i = 0; i < kvm->online_vcpus.counter; i++) { ... } } raw_spin_unlock(vm_lock); Thanks in advance, Alex BInun On Wed 28 May 21:44 2014 Dave Allan wrote:
On Wed, May 28, 2014 at 11:28:19AM -0600, Eric Blake wrote:
On 05/28/2014 09:14 AM, Alexander Binun wrote:
[can you convince your mailer to wrap long lines?]
I have a program running on a VM guest. Its output is valuable (for VM introspection) so I want to let the host module know about it. I prefer to redirect ' stdio" of a guest into a device at the host (a text file or my device that has the name "mydev" and the driver is written for it).
I have the XML definition file for my VM in /etc/libvirt/qemu. I have added the section:
<serial type="file"> <source path="/var/log/vm/vml.log"/> <target port="0"/> </serial>
into the /devices section.
That is I want the stdio to be streamed into the file /var/log/vm/vml.log at the host.
Then I run simple textual commands at the guest (ls, pwd and so on).
How are you getting into your guest to run those commands? Did you connect to your guest's serial console, or is it in a gui window, or via an ssh session, or...? Are you sure the commands you are executing have the guest's /dev/ttyS0 as their stdout?
Your xml is correct and I think Eric's suggestion is right: if I put that <serial> snippet into a guest's XML and then echo "foo" > /dev/ttyS0 in the guest, I see "foo" in the host vml.log.
But I do not see /var/log/vm/vml.log created at the host.
I'm not sure whether libvirt will pre-create the file, or whether it insists that the file already exists. Maybe others can chime in. I know Dave Allan has done some work with python scripts that faithfully capture all text output to the guest's serial console, although I don't have a handy link to that sample script.
The example script is consolecallback.py[1] but it really deals more with auto connecting to a serial console when a VM is booted than with doing anything special with the output, although it's useful if you have a VM going up and down and you want all its console output.
Dave
[1] http://libvirt.org/git/?p=libvirt-python.git;a=blob;f=examples/consolecallba...
-- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org