On Tue, Feb 04, 2014 at 04:15:09PM +0100, Olaf Hering wrote: > On Tue, Feb 04, Richard W.M. Jones wrote: > > > > It seems to me that output is only shown once cmd.sh has finished. I > > > already split cmd.sh into smaller pieces to see overall progress. But > > > output from a verbose, long running single command within cmd.sh is not > > > shown. > > > > Verbose output is carried over a separate channel from qemu, so things > > like kernel messages appear asynchronously: > > > > https://github.com/libguestfs/libguestfs/blob/master/src/conn-socket.c#L301 > > Thanks. > > I think doing 'cmd < /dev/null &> /dev/kmsg' will help, I will try that > way to see whats actually going on.
It kinda works. It looks like /dev/kmsg itself is rather limited. It returns -EINVAL if you try to write "too much" data, or if you read from it "wrongly" or try to seek at all. $ virt-builder fedora-20 [ 1.0] Downloading: http://libguestfs.org/download/builder/fedora-20.xz [ 2.0] Planning how to build this image [ 2.0] Uncompressing [ 12.0] Opening the new disk [ 27.0] Setting a random seed [ 27.0] Setting random root password [did you mean to use --root-password?] Setting random password of root to ITqiAG1tvoFvt5X7 [ 27.0] Finishing off Output: fedora-20.img Output size: 4.0G Output format: raw Total usable space: 5.2G Free space: 4.5G (86%) $ guestfish -a fedora-20.img -i -v sh "yes test < /dev/null > /dev/kmsg 2>&1" [...] /bin/sh -c yes test < /dev/null > /dev/kmsg 2>&1 [ 1.813367] yes: standard output: Invalid argument [ 1.813847] yes: write error umount /sysroot/sys umount /sysroot/proc umount /sysroot/dev guestfsd: error: guestfsd: main_loop: proc 111 (sh) took 0.02 seconds libguestfs: error: sh: The order of the messages from guestfish indicates that the error from 'yes' was being logged to kernel messages and was being sent over the verbose channel before the RPC returned. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/ _______________________________________________ Libguestfs mailing list [email protected] https://www.redhat.com/mailman/listinfo/libguestfs
