Just read the announcement from Citrix that by the end of March 2009, the full enterprise-level class of XenServer will be free of charge. Citrix’s XenServer is based on open source Xen and the company have developed a bunch of GUI tools for ease of installation and management.
The announcement can be read here: http://www.citrix.com/English/NE/news/news.asp?newsID=1687130
Πολλές από τις σημαντικότερες εφευρέσεις των τελευταίων αιώνων έχουν γίνει από Σκωτσέζους. Εφευρέσεις που άλλαξαν κυριολεκτικά τον κόσμο και που χρησιμοποιούμε στη καθημερινή μας ζωή. Ακολουθεί λίστα με τους σημαντικότερους εφευρέτες και των κυριότερων έργων τους:
Και η λίστα συνεχίζεται…
“A critical vulnerability has been identified in Adobe Reader 9 and Acrobat 9 and earlier versions. This vulnerability would cause the application to crash and could potentially allow an attacker to take control of the affected system. There are reports that this issue is being exploited.
Adobe is planning to release updates to Adobe Reader and Acrobat to resolve the relevant security issue. Adobe expects to make available an update for Adobe Reader 9 and Acrobat 9 by March 11th, 2009. Updates for Adobe Reader 8 and Acrobat 8 will follow soon after, with Adobe Reader 7 and Acrobat 7 updates to follow. In the meantime, Adobe is in contact with anti-virus vendors, including McAfee and Symantec, on this issue in order to ensure the security of our mutual customers. A security bulletin will be published on http://www.adobe.com/support/security as soon as product updates are available.”
http://www.adobe.com/support/security/advisories/apsa09-01.html
Quick solution to avoid unexpected behaviour, use a different PDF viewer. Alternatives are available for Linux (Xpdf, Kpdf, Evince), *BSD (Xpdf), OS X (Preview) and Windows (Foxit).
Για να φύγει το μήλο και να φένεται τι γίνεται κατά τη διάρκεια της εκκίνησης:
# nvram boot-args=-v
ή κρατημένο το ‘v’ όταν εκκινεί το σύστημα.
New release of the Xen component for LCFG. It has the previous patches applied.
– Creates the top level directory for a disk image to be stored in case it doesn’t exist (otherwise would fail on creating the disk image)
– Fixes typo bug for detecting the network interfaces at component start and start the Xen bridge interface
RPM: http://lcfg.ucs.ed.ac.uk/pkgs/devolved/world/sl5/rpms/lcfg-xen-0.99.5-1.noarch.rpm
Source RPM: http://lcfg.ucs.ed.ac.uk/pkgs/devolved/world/sl5/srpms/lcfg-xen-0.99.5-1.src.rpm
Η δημιουργία χρηστών και ομάδων στο OS X 10.5.x μέσω του τερματικού μπορεί να προκαλέσει εύκολα πονοκέφαλο. Πρέπει να γίνει πολλαπλή χρήση του Directory Service command line utility όπως περιγράφεται εδώ. Τα συμάζεψα λίγο σε ένα απλό script μαζί με τη δυνατότητα διαγραφής του χρήστη, καθώς και δημιουργία και διαγραφή ομάδων.
#!/bin/bash
function reconfDirServ() {
killall -HUP DirectoryService
}
echo "|-----------------------------------|"
echo "| OS X Users and Groups |"
echo "|-----------------------------------|"
echo "| 1. Add a user -----------------|"
echo "| 2. Delete user -----------------|"
echo "| 3. Add a group -----------------|"
echo "| 4. Delete group -----------------|"
echo "|-----------------------------------|"
echo
echo -n "Option : "; read input
iif [ $input -eq 1 ]; then
echo -n "Username : "; read username
dscl . -create /Users/$username
echo -n "Default shell [/bin/bash]: "; read defaultshell
if [ -z $defaultshell ]; then defaultshell="/bin/bash"; fi
dscl . -create /Users/$username UserShell $defaultshell
echo -n "Full name: "; read fullname
dscl . -create /Users/$username RealName "$fullname"
echo -n "User ID: "; read userid
dscl . -create /Users/$username UniqueID $userid
dscl . -create /Users/$username PrimaryGroupID 20
echo -n "Will $username to be an administrator (Y/N) [N]: "; read adminfunc
if [ -z $adminfunc ]; then adminfunc="n";fi
if [ "$adminfunc" == "y" ] || [ "$adminfunc" == "Y" ]; then
dscl . -append /Groups/admin GroupMembership $username
fi
mkdir /Users/$username
dscl . -create /Users/$username NFSHomeDirectory /Users/$username
passwd $username
chown $userid:staff /Users/$username
reconfDirServ
elif [ $input -eq 2 ]; then
echo -n "Username: "; read username
dscl . -delete /Users/$username
rm -Rf /Users/$username
reconfDirServ
elif [ $input -eq 3 ]; then
echo -n "Group name: "; read groupname
dscl . -create /Groups/$groupname
echo -n "Group ID: "; read groupid
dscl . -create /Groups/$groupname GroupID $groupid
reconfDirServ
exit 0
elif [ $input -eq 4 ]; then
echo -n "Group name: "; read groupname
dscl . -delete /Groups/$groupname
reconfDirServ
else
echo "Select from options 1 - 4"
fi
Τα XML αρχεία των χρηστών και των ομάδων βρίσκονται στο /var/db/dslocal/nodes/Default/users και /var/db/dslocal/nodes/Default/groups αντίστοιχα.
When configuring a Xen virtual machine you can specific the initial memory the VM will use as well the maximum memory the machine cn be assigned with. The Xen management interface gives the ability to change the memory of the VM on-the-fly, without restarting any daemons or the VM. In the following example the memory is dropped down from 1G to 768M using the ‘xm’ command with the ‘mem-set’ option:
# xm list node1 Name ID Mem(MiB) VCPUs State Time(s) node1 1 1023 2 -b---- 115.5 # xm mem-set node1 768 # xm list node1 Name ID Mem(MiB) VCPUs State Time(s) node1 1 767 2 -b---- 115.7
The maximum memory the VM will be able to get is 1024M as this is the maxmem definition in its configuration file.
The Xen management interface enables very easy the to pin specific CPUs to VCPUs without affecting any running VMs. In the following example core 2 is mapped to VCPU0 and core 3 is mapped to VCPU1. The VM will now exclusively use these cores for each of the VCPUs rather than switching depending on workload etc.
# xm vcpu-list node1 Name ID VCPUs CPU State Time(s) CPU Affinity node1 1 0 3 -b- 61.1 2-3 node1 1 1 2 -b- 54.4 2-3 # xm vcpu-pin node1 0 2 # xm vcpu-pin node1 1 3 # xm vcpu-list node1 Name ID VCPUs CPU State Time(s) CPU Affinity node1 1 0 2 -b- 61.1 2 node1 1 1 3 -b- 54.4 3
One more very helpful use of the management interface is that it can trun on and off the VCPUs on a VM. Of course, the last one left on can’t be turned off and the most you can turn on are as the number defined in the configuration file.
# xm vcpu-set node1 1 # xm vcpu-list node1 Name ID VCPUs CPU State Time(s) CPU Affinity node1 1 0 2 -b- 61.3 2 node1 1 1 - --p 54.4 3 # xm vcpu-set node1 2 # xm vcpu-list node1 Name ID VCPUs CPU State Time(s) CPU Affinity node1 1 0 2 -b- 61.4 2 node1 1 1 3 -b- 54.5 3
All the commands above worked perfectly on a paravirtualized Scientific Linux 5.2 VM.
EDIT: The same commands can be used for Domain-0, the machine that hosts the VMs.
I wrote the following script to make identical clones of a Xen virtual machine template. The script will copy the disk image and edit the necessary files of the guest operating system such as /etc/hosts, /etc/sysconfig/network and /etc/sysconfig/network-scripts/ifcfg-eth0. It will replace the hostname and will generate a new MAC address both for the guest OS ifcfg-eth0 file and the guest configuration file which is located under /etc/xen on the host.
Usage:
./xenclone <disk images dir> <disk name> <clone name>
#!/bin/bash
############################################################################
# Copyright (C) 2009 Panagiotis Kritikakos <pkritika@epcc.ed.ac.uk> #
# #
# This program is free software: you can redistribute it and/or modify #
# it under the terms of the GNU General Public License as published by #
# the Free Software Foundation, either version 3 of the License, or #
# (at your option) any later version. #
# #
# This program is distributed in the hope that it will be useful, #
# but WITHOUT ANY WARRANTY; without even the implied warranty of #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
# GNU General Public License for more details. #
# #
# You should have received a copy of the GNU General Public License #
# along with this program. If not, see <http://www.gnu.org/licenses/>. #
############################################################################
if [ $UID != "0" ]; then
echo " You must be root to run the script or run it with sudo"
exit 1;
fi
if [ $# -lt 3 ]; then
echo " Usage: ./xenclone <disk images dir> <disk name> <clone name>"
echo " The script assumes the guest being clone is a Red Hat based system"
exit 1;
fi
DISKPATH=$1
DISK=$2
CLONE=$3
MOUNTDIR=`mktemp -d`
if [ ! -e $DISKPATH/$DISK.img ]; then
echo " Primary disk image can't be found."
exit 1;
fi
clear
TEMPF1=`mktemp`
TEMPF2=`mktemp`
TEMPF3=`mktemp`
TEMPHOSTS=`mktemp`
TEMPNETWORK=`mktemp`
TEMPIFCFG=`mktemp`
echo "Copying ${DISK} to ${CLONE}..."
dd if=$DISKPATH/$DISK.img of=$DISKPATH/$CLONE.img
echo "Mapping the image..."
loopPart=`kpartx -l $DISKPATH/$CLONE.img | awk {'print $1'}`
kpartx -a $DISKPATH/$CLONE.img
echo "Mounting the image..."
mount /dev/mapper/$loopPart $MOUNTDIR
echo "Editing files and creating configuration file for ${CLONE}..."
sed "s/$DISK/$CLONE/g" < $MOUNTDIR/etc/hosts > $TEMPHOSTS
cp -f $TEMPHOSTS $MOUNTDIR/etc/hosts
sed "s/$DISK/$CLONE/g" < $MOUNTDIR/etc/sysconfig/network > $TEMPNETWORK
cp -f $TEMPNETWORK $MOUNTDIR/etc/sysconfig/network
sed "s/$DISK/$CLONE/g" < /etc/xen/$DISK > $TEMPF1
olduuid=`grep uuid $TEMPF1 | awk {'print $3'} | sed s/'"'*'"'//g`
newuuid=`uuidgen`
sed "s/$olduuid/$newuuid/g" < $TEMPF1 > $TEMPF2
oldmac=`grep mac $TEMPF2 | sed s/vif.*mac=//g | sed s/,.*']'//g`
newmac=`echo $RANDOM | openssl md5 | sed 's/\(..\)/\1:/g' | cut -b1-17`
oldhwaddr=`grep HWADDR $MOUNTDIR/etc/sysconfig/network-scripts/ifcfg-eth0
\ | sed s/HWADDR.*=//g`
sed "s/$oldmac/$newmac/g" < $TEMPF2 > $TEMPF3
cp -f $TEMPF3 /etc/xen/$CLONE
sed "s/$oldhwaddr/$newmac/g" < $MOUNTDIR/etc/sysconfig/network-scripts/ifcfg-eth0
\ > $TEMPIFCFG
cp -f $TEMPIFCFG $MOUNTDIR/etc/sysconfig/network-scripts/ifcfg-eth0
echo "Removing temporary files..."
rm -f $TEMPF1 $TEMPF2 $TEMPF3 $TEMPHOSTS $TEMPNETWORK $TEMPIFCFG
echo "Unmounting the image..."
umount /dev/mapper/$loopPart
echo "Unmapping the image..."
kpartx -d $DISKPATH/$CLONE.img
echo "Cloning of ${DISK} to ${CLONE} finished."
Συνήθως η Δεύτερα δεν είναι η πιο ευχάριστη μέρα της εβδομάδας… εκτός και αν είναι λευκή…
: | : vortex of false deceit : | : 
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