diff --git a/lib/nova_plugins/functions-libvirt b/lib/nova_plugins/functions-libvirt
index dae55c6eba..4f9b239a1e 100644
--- a/lib/nova_plugins/functions-libvirt
+++ b/lib/nova_plugins/functions-libvirt
@@ -110,10 +110,10 @@ EOF
             local log_filters="1:libvirt 1:qemu 1:conf 1:security 3:object 3:event 3:json 3:file 1:util 1:qemu_monitor"
         fi
         local log_outputs="1:file:/var/log/libvirt/libvirtd.log"
-        if ! grep -q "log_filters=\"$log_filters\"" /etc/libvirt/libvirtd.conf; then
+        if ! sudo grep -q "^log_filters=\"$log_filters\"" /etc/libvirt/libvirtd.conf; then
             echo "log_filters=\"$log_filters\"" | sudo tee -a /etc/libvirt/libvirtd.conf
         fi
-        if ! grep -q "log_outputs=\"$log_outputs\"" /etc/libvirt/libvirtd.conf; then
+        if ! sudo grep -q "^log_outputs=\"$log_outputs\"" /etc/libvirt/libvirtd.conf; then
             echo "log_outputs=\"$log_outputs\"" | sudo tee -a /etc/libvirt/libvirtd.conf
         fi
     fi