On Monday, March 20, 2017 7:36:14 AM EDT Martin Kletzander wrote:
On Thu, Mar 16, 2017 at 09:04:52PM -0400, Steve Grubb wrote:
>Hello,
>
>I apologize for the delay.
>
>On Tuesday, March 14, 2017 7:42:27 AM EDT Martin Kletzander wrote:
>> I am going through the fields in the dictionary and I can't find any
>> name to use for the following scenario.
>>
>> We (libvirt) are running virtual machines and there's a thing nowadays,
>> that people like to use, called ivshmem (Inter-VM SHared MEMory). From
>> host's point of view this is just a shared memory region accessed by
>> multiple VMs (and possibly to host as well). The machine maps the
>> shared memory given a name (e.g. name "asdf" results in /dev/shm/asdf
to
>> be mapped) *or* it can communicate with a server over UNIX socket and
>> that server handles interrupts and also tells the client which shared
>> memory region to map.
>
>If both of these result in a path, then I think we want to log it as a
>resource event.
Yes, and they both are resources in its sense. So you are talking
particularly about the resrc= field? Should that also have category and
class or anything else set? Or do you mean we report the path in the
resrc= field?
No, I mean we would want the path to the memory in a VIRT_RESOURCE event. :-)
How about something like this:
type=VIRT_RESOURCE msg=audit(1488441043.591:2977): pid=25464 uid=0
auid=4294967295 ses=4294967295 subj=system_u:system_r:virtd_t:s0-s0:c0.c1023
msg='virt=kvm resrc=shmem reason=start vm="rhel7.3" uuid=a7708061-
faa0-42ce-897a-e92fb75fcf1d size=4194304 path="/dev/shm/my_shmem1"
exe="/usr/
sbin/libvirtd" hostname=? addr=? terminal=? res=success'
Having the full path would make it more normal when reporting on files in use.
>> Talking about information we have; in server-less
>> setup it's the shared memory region that is shared, in the server
>> scenario it is the socket. That's information we can output.
>
>Above you mentioned that the server communicates which region to map. Can
>you explain what that means?
The server sends a file descriptor to the VM over the socket, details
can be found here:
http://git.qemu-project.org/?p=qemu.git;a=blob;f=docs/specs/ivshmem-spec.txt
#l151
This one is harder. What we really want to know is the size information. But
libvirtd doesn't have it I assume. That makes it sound like ivshmem should log
it, but it probably doesn't know the reason, vm name, or uuid or anything
else. So, this is probably not good.
I guess about all that you can say is that a ivshmem-socket is being assigned.
I guess let's do it like this:
type=VIRT_RESOURCE msg=audit(1488441043.591:2977): pid=25464 uid=0
auid=4294967295 ses=4294967295 subj=system_u:system_r:virtd_t:s0-s0:c0.c1023
msg='virt=kvm resrc=ivshmem-socket reason=start vm="rhel7.3" uuid=a7708061-
faa0-42ce-897a-e92fb75fcf1d ivshmem="my_shmem2"
exe="/usr/sbin/libvirtd"
hostname=? addr=? terminal=? res=success'
-Steve
>> So my question is, when starting a domain or
hot-(un)plugging, what
>> naming should we use for this kind of device and what are the things
>> that we should describe about it? Basically, how would you like the
>> message to look?
>
>We need a record recording what is getting assigned to the VM. In the case
>of the /dev/shm, you can record that as a path which must be escaped. In
>the case of the server, I think we still need to understand what is
>happening. Just recording a socket number or path is not terribly useful
>in reconstructing the resources given to the VM.
>
>Audit events have to tell a story. There is a subect, object, action, and
>results. It kind of needs to be a sentence. "libvirtd successfully assigned
>____ to vm-name."
>
>-Steve
>
>> Thanks in advance for any info.
>>
>> Have a nice day,
>> Martin