IIRC Openstack adds two in most cases, like:
<serial type='file'>
<source path='/var/lib/nova/instances/7c0dcd78-d6b4-4575-a882-ee5d29c64fe0/console.log'/>
<target port='0'/>
<alias name='serial0'/>
</serial>
<console type='file'>
<source path='/var/lib/nova/instances/7c0dcd78-d6b4-4575-a882-ee5d29c64fe0/console.log'/>
<target type='serial' port='0'/>
<alias name='serial0'/>
</console>
Twice the same path btw, but also same alias.
I checked and that still means only 2 files per guest.
The default guest log like:
/var/log/libvirt/qemu/x-test1.log
And the file redirected console like:
/tmp/consoleIDX2.log
So under these conditions the assumption of ~4096 should work.
In detail I found that under this config there also are 2 pipes along the two logs.
So a single guest looks like:
l-wx------ 1 root root 64 Sep 25 20:48 22 -> /var/log/libvirt/qemu/x-test3.log
lr-x------ 1 root root 64 Sep 25 20:48 23 -> pipe:[5014140]
l-wx------ 1 root root 64 Sep 25 20:48 24 -> /tmp/consoleIDX3.log
lr-x------ 1 root root 64 Sep 25 20:48 25 -> pipe:[5014157]
With 5 guests I had 20 new FDs on the virtlogd service.
That said the limit should still be enough for 1024 guests.
Testing against those numbers now ...
IIRC Openstack adds two in most cases, like: var/lib/ nova/instances/ 7c0dcd78- d6b4-4575- a882-ee5d29c64f e0/console. log'/> var/lib/ nova/instances/ 7c0dcd78- d6b4-4575- a882-ee5d29c64f e0/console. log'/>
<serial type='file'>
<source path='/
<target port='0'/>
<alias name='serial0'/>
</serial>
<console type='file'>
<source path='/
<target type='serial' port='0'/>
<alias name='serial0'/>
</console>
Twice the same path btw, but also same alias. log/libvirt/ qemu/x- test1.log consoleIDX2. log
I checked and that still means only 2 files per guest.
The default guest log like:
/var/
And the file redirected console like:
/tmp/
So under these conditions the assumption of ~4096 should work. libvirt/ qemu/x- test3.log 3.log
In detail I found that under this config there also are 2 pipes along the two logs.
So a single guest looks like:
l-wx------ 1 root root 64 Sep 25 20:48 22 -> /var/log/
lr-x------ 1 root root 64 Sep 25 20:48 23 -> pipe:[5014140]
l-wx------ 1 root root 64 Sep 25 20:48 24 -> /tmp/consoleIDX
lr-x------ 1 root root 64 Sep 25 20:48 25 -> pipe:[5014157]
With 5 guests I had 20 new FDs on the virtlogd service.
That said the limit should still be enough for 1024 guests.
Testing against those numbers now ...