If you're like me, you run libvirt on a headless server and look at VM consoles with virt-viewer. You also probably see the following warnings:
Gtk-Message: 14:08:40.348: Failed to load module "canberra-gtk-module" Gtk-Message: 14:08:40.348: Failed to load module "pk-gtk-module" Gtk-Message: 14:08:40.477: Failed to load module "canberra-gtk-module" Gtk-Message: 14:08:40.477: Failed to load module "pk-gtk-module"
The solution is as follows
yum install PackageKit-gtk3-module libcanberra-gtk3
Here is the magic to get CPAN CLI to work with https.
# cpan
cpan[1]> o conf urllist https://www.perl.com/CPAN
Please use 'o conf commit' to make the config permanent!
cpan[2]> o conf urllist
urllist
0 [https://www.perl.com/CPAN]
Type 'o conf' to view all configuration items
cpan[3]> o conf commit
commit: wrote '/usr/share/perl5/CPAN/Config.pm'
If it is giving you problems with SSL certificat verification, then you have to upgrade openssl, ca-certificate to the latest version. Perl also maintains it's own SSL certificates in Mozilla::CA, so you might need to do
SSL_CERT_FILE=/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem cpan Mozilla::CA
If, like me, you are a fool and still have CentOS 6 installs you have to maintain, you might run into the following problem:
https://vault.centos.org/6.10/os/x86_64/repodata/repomd.xml: [Errno 14] problem making ssl connection Trying other mirror. https://vault.centos.org/6.10/extras/x86_64/repodata/repomd.xml: [Errno 14] problem making ssl connection Trying other mirror. https://vault.centos.org/6.10/updates/x86_64/repodata/repomd.xml: [Errno 14] problem making ssl connection Trying other mirror.
The solution is to update curl and yum by hand:
wget https://vault.centos.org/6.10/os/x86_64/Packages/python-urlgrabber-3.9.1-11.el6.noarch.rpm wget https://vault.centos.org/6.10/updates/x86_64/Packages/yum-3.2.29-81.el6.centos.0.1.noarch.rpm wget https://vault.centos.org/6.10/updates/x86_64/Packages/curl-7.19.7-54.el6_10.x86_64.rpm wget https://vault.centos.org/6.10/updates/x86_64/Packages/libcurl-7.19.7-54.el6_10.x86_64.rpm sudo rpm -Uvh libcurl-7.19.7-54.el6_10.x86_64.rpm curl-7.19.7-54.el6_10.x86_64.rpm yum-3.2.29-81.el6.centos.0.1.noarch.rpm python-urlgrabber-3.9.1-11.el6.noarch.rpm
Instructions on how I set up sendmail smart relay with TLS and plain authenetication on CentOS 6.
First, make sure you have enough installed :
yum -y install ca-certificates sendmail sendmail-cf
Create /etc/mail/authinfo:
AuthInfo:YOUR.HOST.COM "U:YOUR-USER@YOUR.HOST.COM" "I:YOUR-USER" "P:YOUR-PASSWORD" "M:LOGIN PLAIN"
Replace YOUR.HOST.COM, YOUR-USER and YOUR-PASSWORD with the correct stuff. LOGIN PLAIN stays as-is if you are using plaintext logins. Make sure to chmod 0600 this file.
Add the following to /etc/mail/sendmail.mc, making sure you use m4's dumbass `quotation' style
define(`SMART_HOST', `YOUR.HOST.COM')dnl define(`RELAY_MAILER',`esmtp')dnl define(`RELAY_MAILER_ARGS', `TCP $h 587')dnl FEATURE(`authinfo')dnl define(`confCACERT_PATH', `/etc/pki/tls/certs')dnl define(`confCACERT', `/etc/pki/tls/certs/ca-bundle.crt')dnl
Note that the above is TCP port 587, which you might need to change.
Finally you restart sendmail and test as you normally woudl.
chmod 0600 /etc/mail/authinfo service sendmail restart echo "Testing" | mail -s "Test 1" somebody@example.com tail -F /var/log/maillog
So I have a new Lexmark MB2236adw laser printer. For some reason beyond my ken, Windows 10 keeps saying it's offline, when clearly it isn't. Printer works fine from Linux, so I decided that Windows is going to print via CUPS.
First, create a raw printer on your CUPS host:
lpadmin -p hwelraw -v socket://hwel.localdomain:9100 -E \
-D "Lexmark on UPS (raw)" -L "Philip's Office" -o raw
Then add the following to cups.conf to allow printing via the network:
<Location /printers>
Order allow,deny
Allow localhost
Allow 10.0.0.*
</Location>
Remember to restart CUPS
service cups reload
Open up the port 631 in iptables.
Now on the windows computer, install the Lexmark drivers.
Then you have to turn on IPP : Control Panel > Programs > Turn Windows Features On or Off > Print and Document Services > Internet Printing Client must be checked.
Now it's time to Add a printer, using the The printer that I want isn’t listed button. You are going to be using an http URL, that will look like http://scott/pritners/hwelraw. Replace scott with your Linux computer's name and hwelraw with the CUPS queue name. Select the printer driver installed previously, print your test page and bask in the glory of getting a computer to do your bidding.
As a bonus step, print a 2 page document to make sure Windows can print double sided because my new printer does cool things like that.
Furthermore, to get X working nicely on a Shuttle DX30 with CentOS 6, you have to install a newer intel driver:
yum install libpciaccess-devel.x86_64 xorg-x11-server-devel.x86_64 libXfont-devel.x86_64 libXfont2-devel.x86_64 git clone git://anongit.freedesktop.org/xorg/driver/xf86-video-intel cd xf86-video-intel git checkout d39197bb10b7d88cb4c456e7a5e8d34c1dc6eeaf autoreconf -i ./configure make sudo mv /usr/lib64/xorg/modules/drivers/intel_drv.so /usr/lib64/xorg/modules/drivers/intel_drv.so.ORIG sudo rsync -a ./src/.libs/intel_drv.so /usr/lib64/xorg/modules/drivers/intel_drv.so
(Copied from https://www.centos.org/forums/viewtopic.php?t=64780)
So I wanted to get a Shuttle DX30 working under LTSP. First step, it uses a pxe-client-id that's 9 bytes long. CentOS's dhcpd throws away anything that doesn't have a 17 byte pxe-client-id. I have no idea why. I tried poking around the RFCs but didn't find much of interest.
Once I patched dhcped, PXE booting worked and I managed to load a kernel. Except it was slow.
Very.
Very.
Very.
Slow.
Just how slow? It took over 30 minutes to get to a XDM prompt slow.
I saw Machine check events going past. To track those down, I put my laptop's 2.5 inch HDD into it. This was also slow. While not as bad, it was clearly not working properly. But I got mcelog to grab the following:
mcelog: failed to prefill DIMM database from DMI data mcelog: mcelog read: No such device Hardware event. This is not a software error. MCE 0 CPU 0 BANK 4 ADDR fef5d200 TIME 1531800239 Tue Jul 17 00:03:59 2018 MCG status: MCi status: Error overflow Uncorrected error MCi_ADDR register valid Processor context corrupt MCA: Internal unclassified error: 408 Running trigger `unknown-error-trigger' STATUS e600000000020408 MCGSTATUS 0 MCGCAP c07 APICID 0 SOCKETID 0 CPUID Vendor Intel Family 6 Model 92
After some messing around, cursing the Gods, discussing Intel NUCs on #ltsp, general lack of sleep, I found the solution : kernel-ml
yum -y --enablerepo=elrepo-kernel install kernel-ml joe /etc/grub.conf # set default=0
It should be noted it took over 10 minutes for dracut to create the initrd for kernel-ml. But once I then booted into the new kernel, everything was fine. I installed kernel-lt as a test, because it needs the CPU and the disk to run smoothly and it took 2 minutes, which is annoying but expected. For reference, installing kernel-ml on my desktop takes 1.5 minutes but it has an SSD.
kernel-lt was a failure, 9m54 to install kernel-ml-4.17.5-1.el6.elrepo.x86_64. I booted back into kernel-ml, removed and reinstalled kernel-ml-4.17.5-1.el6.elrepo.x86_64 and it took 1m52. So kernel-ml is the clear winner.
Now to find out how to install kernel-ml into LTSP.
I run daemontools from upstart. I ran into a problem that one of my daemons needed dbus to be working, but upstart was starting daemontools before rc had a chance to start it. The bigger problem is that CentOS 6 is only a partial conversion to upstart in that it still uses rc files for most things.
I used to have start on runlevel [345] in /etc/init/daemontools.conf but that means daemontools is started at the same time (or even before) as rc.
I tried start on started rc but that means daemontools runs after rc is launched, not after rc has finished.
The solution is a custom event :
cat <<'SH' >/etc/init.d/rc-done #!/bin/sh # # rc-done Emits events when rc has finished or nearly # # chkconfig: 2345 99 01 [ -e /etc/sysconfig/rc-done ] && . /etc/sysconfig/rc-done case "$1" in start) initctl emit rc-done ;; stop) initctl emit rc-start ;; *) echo $"Usage: $0 {start|stop}" exit 2 esac exit $? SH chmod +x /etc/init.d/rc-done chkconfig --add /etc/init.d/rc-done
Now we put start on rc-done into daemontools.conf
Of course the interesting part is initctl emit rc-done. We could just as easily have put that at end of rc.local.
First we need /etc/init/dgrp.conf.
# Digi EtherLite
# Starts a agetty for each serial port
# Normally run from the start-dgrp.conf task
stop on runlevel [S016]
env TERM=vt100
env BAUD=19200
respawn
instance $ID
exec /sbin/agetty -L tty$ID ${BAUD:-19200} ${TERM:-vt100}
usage 'dgrp ID=XX [BAUD=YYYYY] [TERM=ZZZZ] - where XX is terminal id (A10) and YYYYY is baud (12900) and ZZZZ is the termcap entry (vt100)'
You can test this by starting an agetty on ttyA01 with:
initctl start dgrp ID=A01
Stop it with:
initctl stop dgrp ID=A01
Now create /etc/sysconfig/dgrp. Each line is the ID with an optional baud rate (default 19200) and TERM (default vt100) setting:
A01 A02 9600 vt100 A10 19200 wy60
Now we create the controlling task. This gets run after rc?.d is finished. It reads /etc/sysconfig/dgrp and runs dgrp.conf where needed.
# Digi Etherlite
# This task will read /etc/sysconfig/dgrp and will run dgrp.conf for each line in it
# It is run after all rc?.d the scripts are run
start on stopped rc RUNLEVEL=[2345]
env CONFIG=/etc/sysconfig/dgrp
task
script
test -f $CONFIG || ( logger -t start-dgrp.conf "$CONFIG doesn't exist"; exit 0 )
test -d /proc && test -d /proc/dgrp || ( logger -t start-dgrp.conf "drpd daemon is not running" ; exit 3 )
temp=$(mktemp --tmpdir)
grep -v '#' $CONFIG >$temp
while read ID BAUD TERM ; do
ID=$(basename $ID)
initctl start dgrp ID=${ID/tty} BAUD=$BAUD TERM=$TERM
done < $temp
end script
We use a temporary file so that we can ignore comments in the dgrp config file.
Mozilla projects offer to check the spelling in every language installed on your computer. Which is great, except I don't need South African English, nor will I ever use Swiss French. And wading through the 20 items in the menu to switch from Canadian English to Québecois French is annoying.
And there is no easy way to fix this.
The hard way is to go into /usr/share/myspell and remove all the .dic and .aff files you don't want.
$ sudo su - Password for fil@scott: # cd /usr/share/myspell/ # mkdir NOT # mv *.dic *.aff NOT # ln -s NOT/fr_CA.aff # ln -s NOT/fr_CA.dic # ln -s NOT/en_CA.aff # ln -s NOT/en_CA.dicRestart Thunderbird and you will now have 2 spelling options.
Yes, these changes are system-wide. There is currently no other way to do it, apparently.
This is how you install vmware-vdiskmanager on CentOS 6. I needed to do this so I could read my old vmware-server vmdk.
First go this old KB article and download 1023856-vdiskmanager-linux.7.0.1.zip. It's at the bottom, in the Attachements section. Now you do the following little dance:
unzip 1023856-vdiskmanager-linux.7.0.1.zip cp 1023856-vmware-vdiskmanager-linux.7.0.1 /usr/local/sbin/vmware-vdiskmanager chmod +x /usr/local/sbin/vmware-vdiskmanager yum -y install zlib.i686 glibc.i686 openssl098e.i686 md -pv /usr/lib/vmware/lib cd /usr/lib/vmware/lib/ ln -s /usr/lib/libcrypto.so.0.9.8e ln -s libcrypto.so.0.9.8e libcrypto.so.0.9.8 ln -s libcrypto.so.0.9.8e libcrypto.so.0 ln -s libcrypto.so.0.9.8e libcrypto.so ln -s /usr/lib/libssl.so.0.9.8e ln -s libssl.so.0.9.8e libssl.so.0.9.8 ln -s libssl.so.0.9.8e libssl.so.0 ln -s libssl.so.0.9.8e libssl.so
That fucking around in /usr/lib/vmware/lib is because even though VMware claims this is a static binary, it in fact dynamically loads crypto libraries at run time from non-standard places.
You can now convert your split vmdk to a single file and mount it:
vmware-vdiskmanager -r sda.vmdk -t 0 sda-single.vmdk modprobe nbd max_part=8 qemu-nbd -r --connect=/dev/nbd0 sda-single.vmdk kpartx -a /dev/nbd0 vgscan vgchange -a y YOURVG mount -o ro /dev/mapper/YOURVG-YOURLV /mnt
Aren't you glad you created a unique VG for each of your VMs?
To unmount:
umount /mnt vgchange -a n YOURVG kpartx -d /dev/nbd0 qemu-nbd -d sda-single.vmdk
This is how you setup a babysitter for a service started with system V init scripts using DJB's deamontools. We can't just put service $service start into a run file, because sys V init scripts start up background daemons. We have to use the daemon's PID file to watch what's going on.
First, I create mysql-babysit. I'm using mysql as an example. For other services, adjust $service and $pidfile.
# mkdir /var/daemontools/supervised/mysql-babysit # cd /var/daemontools/supervised/mysql-babysit # cat <<'SH' > mysql-babysit #!/bin/bash service=mysql datadir=/var/lib/mysql pidfile=$datadir/$(hostname).pid ################## sleepPID= function sig_finish () { echo $(date) $service "$1" service $service stop [[ $sleepPID ]] && kill $sleepPID } trap 'sig_finish TERM' TERM trap 'sig_finish KILL' KILL ################## echo $(date) $service start service $service start if [[ -f $pidfile ]] ; then pid=$(< $pidfile) if [[ $pid ]] ; then while grep -q $service /proc/$pid/cmdline 2>/dev/null ; do sleep 60 & sleepPID=$! wait $sleepPID done echo $(date) $service exited exit 0 fi fi echo $(date) $service failed to start sleep 5 exit 3 SH
Next we create and activate the run script
cd /var/daemontools/supervised/mysql-babysit # cat <<'SH' >run #!/bin/bash exec /var/daemontools/supervised/mysql-babysit/mysql-babysit SH # chmod +x run # chkconfig mysql off # service mysql stop # cd ../../service # ln -s ../supervised/mysql-babysit
We can control mysql with
svc -d /var/daemontools/supervised/mysql-babysit # shutdown mysql svc -u /var/daemontools/supervised/mysql-babysit # startup mysql killall mysql # restart mysql
I've had a Wacom Intuos 5x4 since 1998 or so. But support for the serial protocol it used has disappeared. What's more, my tablet was getting really crusty over nearly 20 years of use. So I went and bought a Wacom Intuos Photo, which has a smaller, wider surface (which is useful given I have 2 screens) but also can use a finger instead of a pen.
Of course, the new tablet didn't work out of the box. Well, it nearly worked.
Back in the day, I patched wacom_drv for XFree86 to get it working. Things have changed greatly since then. On modern Linux, the driver is in the kernel (wacom.ko) which creates an input and event device. X.org then uses HAL to enumerate input devices and HAL also provides hints on how to configure them. The long and short is we no longer need to mess around in xorg.conf when we change hardware. However, it means it gets very hard to debug when one of those layers does something annoying.
The easy way to get an Wacom Intuos Photo, Draw, Art to work on CentOS 6 is to install the backports of linuxwacom drivers. If you are running the stock 2.6.32 kernel, everything will Just Work.
I'm using the elrepo's 4.10 kernel-ml. This gets lm-sensors working for my motherboard and removes an annoying bug with my PS/2 keyboard.
In 4.10 kernel, the wacom driver is recognizing the tablet and doing it's job : creating 3 input event IDs one for the pad, one for the stylus and one for finger touch. However, lshal is rejecting the finger touch. I traced it down to HAL_PROP_BUTTON_TYPE not being set when hald-probe-input is called. This means the stylus automatically works on X.org, but touch doesn't.
To get finger touch to work on X.org, I had to force things. First, I need to create a symlink to the finger event ID using udev, then a partial config file for X.org :
/usr/local/lib/udev/wacom-type.sh will output a short name for each device it is called on. Make sure this script is executable!
#!/bin/bash
name=$(cat /sys/$DEVPATH/device/name)
# echo "$DEVPATH=$name" >>/tmp/wacom-dev.txt
shopt -s nocasematch
if [[ $name =~ Finger ]] ; then
echo finger
elif [[ $name =~ Pen ]] ; then
echo pen
elif [[ $name =~ Pad ]] ; then
echo pad
else
echo unknown
fi
exit 0
/etc/udev/rules.d/99-wacom.rules convinces udevd to call the above when the tablet is detected. It also convinces udevd to create a symlink in /dev/input/wacom-finger. Note that I restrict to 056a:033c, which is a Wacom Intuos Draw/Photo/Art small version. You can find the USB ID of your tablet with lsusb.
#
# Will create /dev/input/wacom-finger, I hope
#
ACTION!="add|change", GOTO="my_wacom_end"
KERNEL!="event*", GOTO="my_wacom_end"
ENV{ID_VENDOR_ID}!="056a", GOTO="my_wacom_end"
ENV{ID_MODEL_ID}=="033c", PROGRAM=="/usr/local/lib/udev/wacom-type.sh", SYMLINK+="input/wacom-%c"
LABEL="my_wacom_end"
Test the above by doing udevadm control --reload-rules, unplug tablet, wait, plug in tablet, then ls -l /dev/input and you should see:
lrwxrwxrwx 1 root root 7 Mar 22 15:50 wacom-finger -> event11 lrwxrwxrwx 1 root root 7 Mar 22 15:50 wacom-pad -> event12 lrwxrwxrwx 1 root root 7 Mar 22 15:50 wacom-pen -> event10
The numbers after event will change each time you reboot or replug the tablet.
/etc/X11/xorg.conf.d/wacom.conf will finally convince X.org to use the Wacom finger event id as a touch pad.
Section "InputDevice"
Identifier "Finger"
Driver "wacom"
Option "Vendor" "Wacom"
Option "AutoServerLayout" "on"
Option "Type" "touch"
Option "Device" "/dev/input/wacom-finger"
Option "Mode" "Absolute"
Option "Touch" "on"
Option "Gesture" "off"
# Option "Tilt" "on"
Option "Threshold" "20"
Option "Suppress" "6"
Option "USB" "On"
EndSection
I'd like to very much thank whot and jigpu who spent an impressive amount of time helping me over IRC.
UPDATE: 24 hours later, I have found a problem with the approach. If you unplug and replug the tablet, the Finger event ID will change. And while the wacom-finger symlink will be updated, X.org will not know that it's changed and hold onto the old event ID. This means finger will no longer work after replugging the tablet, at least until you restart X.org.
UPDATE: 1 year later and kernel-ml has gone to 4.16, which won't work. 4.15.15 is the last version that does work.
This means I'm now running CentOS 6 on my desktop ("So soon!?" shut up). It also means I have to fix all the little annoying things about CentOS 6. One of which is that modern kernels us a framebuffer, which switches the console to illegibly small text. The solution is to put video=640x480 or video=800x600 on your kernel command line. Ideally in grub.conf.
Setting up Perl on CentOS 6. I'm putting this here so that I can find it easily.
yum install perl perl-CPAN
cpan
# make everything automatic
o conf prerequisites_policy follow
o conf build_requires_install_policy yes
o conf commit
q
cpan local::lib
cpan Bundle::CPAN # keep an eye on this because Realine wants you to hit enter
cpan App::cpanminus
Now we can install Imager (say)
sudo yum install giflib-devel libjpeg-devel libpng-devel libtiff-devel freetype-devel t1lib-devel cpanm Imager
Firefox keeps lots of useful in sqlite files in the user's profile. Under Linux, you will find these files in ~/.mozilla/firefox/PROFILE_DIR/. To find PROFILE_DIR, you pull look in ~/.mozilla/firefox/profiles.ini. Of interest to me is places.sqlite, which contains info on all sites visited. To pull a list out, simply do
sqlite3 -csv ~/.mozilla/firefox/ucjmuboi.default/places.sqlite \
'SELECT url,title,visit_count,visit_date/1000000 FROM moz_historyvisits JOIN moz_places ON place_id = moz_places.id'
The visit_date is bizarely in microseconds, so divide by 1,000,000 to get epoch seconds.
Of course, the above doesn't work on CentOS 5 nor 6. You wil get a Error: file is encrypted or is not a database error. CentOS 5 ships with sqlite 3.3.6, CentOS 6 ships with 3.6.20. Firefox uses 3.7 and creates a file that isn't backward compatible. Here is how to install a compatible version:
cd ~/work wget http://www.sqlite.org/2016/sqlite-autoconf-3130000.tar.gz tar zxvf sqlite-autoconf-3130000.tar.gz cd sqlite-autoconf-3130000 ./configure --prefix=/opt/sqlite-3130000 make all sudo make install sudo ln -s sqlite-3130000 /opt/sqlite sudo bash -c "echo /opt/sqlite/lib > /etc/ld.so.conf.d/sqlite.conf" sudo ldconfig
This will install 3.13.0. Make sure to check the download page for the latest version.
It should be pointed out that by putting /opt/sqlite/lib into ld.so.conf.d, we are overriding the .so default system .so. I don't know if this will break anything. I do know that it means that DBD::SQLite and /usr/bin/sqlite3 now use the new .so and this is what I want.
It should be noted that SphinxSE wants to talk to searchd on port 9312. SELinux will prevent this. To enable it:
semanage port -a -t mysqld_port_t -p tcp 9312
I'm a strange kind of fool. I maintain my own mysql packages, which makes installing them annoying because everything wants to pull in mysql-libs from the mainline.
I also sometimes want to install mysql in /home/mysql, not /var/lib/mysql as in standard on CentOS. SElinux is set up to prevent just this sort of thing. The short version is that everyhing in /home is has the home_root_t security context, which mysqld and mysqld_safe aren't allowed to interact with.
The solution is the following:
# first we are setting up the directory mkdir -p /home/mysql/{InnoDB,etc,log,data,tmp,bin,sbin} mv /etc/my.cnf /home/mysql/etc ln -s /home/mysql/etc/my.cnf /etc for n in /usr/bin/my* ; do ln -s $n /home/mysql/bin ; done for n in /usr/sbin/my* ; do ln -s $n /home/mysql/sbin ; done chmod 1777 /home/mysql/tmp chown mysql:mysql -R /home/mysql joe /home/mysql/etc/my.cnf # change datadir joe /etc/init.d/mysql # change datadir and basedir # now comes the part where we fight with selinux semanage fcontext -a -t mysqld_db_t "/home/mysql(/.*)?" semanage fcontext -a -t etc_t "/home/mysql/etc(/.*)?" semanage fcontext -a -t bin_t "/home/mysql/bin(/.*)?" semanage fcontext -a -t bin_t "/home/mysql/sbin(/.*)?" semanage fcontext -a -t mysqld_tmp_t "/home/mysql/tmp(/.*)?" semanage fcontext -a -t mysqld_safe_exec_t "/home/mysql/bin/mysqld_safe" restorecon -R -v /home/mysql service mysql start
But it's still failing, because /home/mysql/bin/mysqld_safe is a symlink. To fix this, I did
grep mysqld /var/log/audit/audit.log | audit2allow -M "mysqlhome"
semodule -i mysqlhome.pp
service mysql start
Yay! Now it works
So I'm setting up SAMBA on a new machine, I can connect correctly but dir listings are failing. The problem is SELinux, because I tried setenable 0 and it worked.
So I ask on IRC and find out I need to do the following:
semodule -BD # turn off ignored AVCs # redo the directory listing in another window semodule -B # turn AVCs ignoring on grep smb audit.log | audit2allow # parse those AVCs #============= smbd_t ============== #!!!! This avc can be allowed using one of the these booleans: # samba_export_all_ro, samba_enable_home_dirs, samba_export_all_rw allow smbd_t user_home_t:dir read; setsebool -PV samba_enable_home_dirs 1
I FINALLY found it!
The problem: You are messing around with loopback files and volume groups. You've removed the loopback, but the VG stays in the kernel's internal list. vgremove is of course NOT how you get rid of it.
The sane way of doing this is:
vgchange -a n VolGroup00 kpartx -d /dev/nbd0 qemu-nbd -d /dev/nbd0 vgscan
But maybe you killed qemu-nbd by mistake? Or maybe your partition is long gone. Then you need to use dmsetup to remove all traces:
# ls -l /dev/mapper/ total 0 lrwxrwxrwx. 1 root root 7 Mar 18 22:08 GEORGE2-root -> ../dm-0 lrwxrwxrwx. 1 root root 7 Mar 18 22:08 GEORGE2-swap -> ../dm-1 lrwxrwxrwx. 1 root root 7 Mar 19 15:44 Test02-LogVol00 -> ../dm-4 lrwxrwxrwx. 1 root root 7 Mar 19 15:44 Test02-LogVol01 -> ../dm-5 crw-rw----. 1 root root 10, 58 Mar 18 22:08 control # dmsetup info /dev/dm-4 Name: Test02-LogVol00 State: ACTIVE Read Ahead: 256 Tables present: LIVE Open count: 0 Event number: 0 Major, minor: 253, 4 Number of targets: 1 UUID: LVM-zo1BvaMXr6TS1knhxoyjhtItHEaIVH4wGJz2s2w8w24za3486Aa9ur0igGMxpLf7 # dmsetup remove /dev/dm-4 # dmsetup remove /dev/dm-5 # vgscan Reading all physical volumes. This may take a while... Found volume group "GEORGE2" using metadata type lvm2
And there was much rejoicing.