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Description of problem: When guest is running, restart virtlogd, then make qemu process produce new log data, it's not writen into $guest.log file. Version-Release number of selected component (if applicable): # git describe v1.3.1-347-gfb2bd20 How reproducible: 100% Steps to Reproduce: 0. Use logd to handle qemu stdout/stderr 1. Prepare a guest with spice graphic and start it # virsh dumpxml $guest ... <graphics type='spice' autoport='yes' listen='0.0.0.0'> <listen type='address' address='0.0.0.0'/> </graphics> ... 2. Open/close spice graphic, check $guest.log: # tailf /var/log/libvirt/qemu/rhel7.2.log main_channel_link: add main channel client main_channel_handle_parsed: net test: latency 48.529000 ms, bitrate 2031746031 bps (1937.624007 Mbps) inputs_connect: inputs channel client create red_dispatcher_set_cursor_peer: ... 3. Check opened FDs # lsof |grep pipe|grep virtlogd virtlogd 28591 root 12r FIFO 0,8 0t0 2205627 pipe virtlogd 28591 28592 root 12r FIFO 0,8 0t0 2205627 pipe # lsof |grep pipe|grep qemu qemu-kvm 28678 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28696 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28696 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28709 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28709 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28710 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28710 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28711 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28711 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28712 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28712 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28714 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28714 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28715 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28715 qemu 2w FIFO 0,8 0t0 2205627 pipe # lsof /var/log/libvirt/qemu/rhel7.2.log COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME virtlogd 28591 root 14w REG 253,0 7168 1345121 /var/log/libvirt/qemu/rhel7.2.log 4.Restart virtlogd # systemctl restart virtlogd 5.Open/close spice graphic again, check $guest.log: # tailf /var/log/libvirt/qemu/rhel7.2.log (no new log data) 6.Check opened FDs again: # lsof /var/log/libvirt/qemu/rhel7.2.log （no output) # lsof |grep pipe|grep qemu qemu-kvm 28678 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28696 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28696 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28709 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28709 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28710 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28710 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28711 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28711 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28712 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28712 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28714 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28714 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28715 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28715 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28778 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28778 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28781 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28781 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28782 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28782 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28783 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28783 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28784 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28784 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28785 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28785 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28786 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28786 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28787 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28787 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28788 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28788 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28789 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28789 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28790 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28790 qemu 2w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28791 qemu 1w FIFO 0,8 0t0 2205627 pipe qemu-kvm 28678 28791 qemu 2w FIFO 0,8 0t0 2205627 pipe # lsof |grep pipe|grep virtlogd virtlogd 28798 root 7r FIFO 0,8 0t0 2210039 pipe virtlogd 28798 root 8w FIFO 0,8 0t0 2210039 pipe virtlogd 28798 root 9r FIFO 0,8 0t0 2210040 pipe virtlogd 28798 root 10w FIFO 0,8 0t0 2210040 pipe virtlogd 28798 28799 root 7r FIFO 0,8 0t0 2210039 pipe virtlogd 28798 28799 root 8w FIFO 0,8 0t0 2210039 pipe virtlogd 28798 28799 root 9r FIFO 0,8 0t0 2210040 pipe virtlogd 28798 28799 root 10w FIFO 0,8 0t0 2210040 pipe As we can see, no new pipes are created between virtlogd and qemu process. Actual results: New qemu log is not writen into log file after restarting virtlogd when guest is running Expected results: New pipes are created and new qemu log can be writen into log file after restarting virtlogd when guest is running Additional info:
Moving to RHEL7, this may be something we want to fix before 7.3. Not sure if it's 'just a bug' or more work than that
This is really not a bug - you should *not* restart virtlogd while guests are running. It is explicitly designed to be able to re-exec itself to allow for live upgrades while it is running, so there should be no reason to restart it fully while guests are running.