[libvirt] [PATCHv2] Do not keep empty log files for deleted domains

[Jan Zerebecki]

With logrotates copytruncate when e.g. domain1 doesn't exist anymore
/var/log/libvirt/qemu/domain1.log will still exist after rotation even
though it will never be written to. When new domain names keep getting
used this leads to a lot of empty logfiles. This may lead to slowdown or
lack of free disk space / inodes.

Fix this by replacing copytruncate with the apropriate postrotate
command to reopen log files. Thus after the apropriate time log files
for deleted domains will be gone. This also has the advantage that the
chance for loss of a few lines during copytruncate is gone.

This only fixes the issue for qemu domains, others still have the same
problem unfixed.

Signed-off-by: Jan Zerebecki <jan.suse at zerebecki.de>
---
v2: drop changes to other logrotate confis

 src/remote/libvirtd.qemu.logrotate.in | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/remote/libvirtd.qemu.logrotate.in b/src/remote/libvirtd.qemu.logrotate.in
index cdb399ef23..95407cec1a 100644
--- a/src/remote/libvirtd.qemu.logrotate.in
+++ b/src/remote/libvirtd.qemu.logrotate.in
@@ -4,5 +4,7 @@
         rotate 4
         compress
         delaycompress
-        copytruncate
+        postrotate
+                /usr/bin/killall -USR1 virtlogd
+        endscript
 }
-- 
2.20.1