Difference between revisions of "Arch VServer"

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[[Category:Emulators (English)]][[Category: HOWTOs (English)]]
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[[Category:Virtualization]]
{{ stub }}
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This article aims to provide all necessary information regarding the creation of a vserver host as well as vserver guests running Arch Linux. This will enable you to setup virtual servers that provide different services as if they were on different machines, with a very little overhead. You can get more information about virtual servers [http://en.wikipedia.org/wiki/Virtual_private_server here].
{{ translateme }}
+
 
+
=Introduction=
+
 
+
This article aims to provide all necessary information regarding the creation of a vserver host as well as vserver guests running ArchLinux. Tis will enable you to setup virtual servers that provide different services as if they were on different machines, with a very little overhead. You can get more information about virtual servers [http://en.wikipedia.org/wiki/Virtual_private_server here].
+
 
+
[disclaimer] I've just started playing around with vserver and am finding the documentation regarding this project lacking. As such, the way I'm doing this below may not be optimal.[/disclaimer]
+
  
 
=Preparing the Host=
 
=Preparing the Host=
  
To prepare the vserver host environment, you will need to install both a vserver patched kernel and the vserver utilities which are located in [http://wiki.archlinux.org/index.php/AUR AUR]. In the following steps, the instructions are provided using [http://wiki.archlinux.org/index.php/Yaourt yaourt] to fetch them automatically. This has the aded benefit of pulling down the required dependencies ( ''dietlibc'' and ''beecrypt'' ) automagically :
+
To prepare the vserver host environment, you will need to install both a vserver patched kernel, the vserver utilities and their dependencies which are located in the [[AUR]]. The required packages are {{AUR|dietlibc}}, {{AUR|beecrypt}}, {{AUR|kernel26-vserver}} (not found or {{AUR|linux-vserver}} orphan), and {{AUR|util-vserver}}
 
+
# yaourt -S kernel26-vserver util-vserver
+
  
 
=Paths of Interest=
 
=Paths of Interest=
Line 27: Line 18:
  
 
If you plan on doing this often, I highly recommend that you write yourself a little batch script since most of these steps can be automated quite easily.
 
If you plan on doing this often, I highly recommend that you write yourself a little batch script since most of these steps can be automated quite easily.
 
'NOTE' : Next step is going to be writing scripts in /usr/lib/util-vservers to integrate pacman into the mix to automagically get everything built up and installed.
 
  
 
==Preparing the guest installation media==
 
==Preparing the guest installation media==
  
'NOTE' : This is all heavily inspired from [http://wiki.archlinux.org/index.php/Install_From_Existing_Linux wiki:Install From Existing Linux] and will therefore be quite brief when not mentioning Vserver specific steps.
+
'''NOTE''' : This is all heavily inspired from [[Install From Existing Linux]] and will therefore be quite brief when not mentioning Vserver specific steps.
  
 
===Optional: Base variables to follow along with the steps===
 
===Optional: Base variables to follow along with the steps===
GuestName= # Name of the guest
+
GuestName= # Name of the guest
GuestRoot=/etc/vservers/.defaults/vdirbase/$GuestName
+
GuestRoot=/etc/vservers/.defaults/vdirbase/$GuestName
GuestPackages= # Listing of packages to install via pacman
+
GuestPackages= # Listing of packages to install via pacman
GuestDisk= # Installation target device
+
GuestDisk= # Installation target device
GuestNetDevice= # ex.: eth0, dummy0, etc...
+
GuestNetDevice= # ex.: eth0, dummy0, etc...
GuestIP= # I think you get it
+
GuestIP= # I think you get it
GuestContext= # Unique identifier for the guest, I go with the last part of the IP
+
GuestContext= # Unique identifier for the guest, I go with the last part of the IP
  
 
===Optional: Preparing the guest disk===
 
===Optional: Preparing the guest disk===
# Create a LVM Physical Volume, a Volume Group and a Logical Volume ( [http://wiki.archlinux.org/index.php/Lvm#Create_Logical_Volumes wiki:LVM] )
+
# Create a LVM Physical Volume, a Volume Group and a Logical Volume ( [https://wiki.archlinux.org/index.php/Lvm#Create_Logical_Volumes wiki:LVM] )
 
# Create a filesystem on the lvm volume
 
# Create a filesystem on the lvm volume
 
# mkdir $GuestRoot
 
# mkdir $GuestRoot
Line 65: Line 54:
  
 
===Install the base system===
 
===Install the base system===
'''NOTE : ''' To save some time, it's probably a good idea to create a text file containing all the packages to install and call it via "pacman -Sy `cat $GuestPackages` -r $GuestRoot" instead of the following :  
+
'''NOTE : ''' To save some time, it's probably a good idea to create a text file containing all the packages to install and call it via "pacman -S `cat $GuestPackages` -r $GuestRoot" instead of the following :  
# pacman -Sy base -r $GuestRoot
+
# pacman -S base -r $GuestRoot
 
# Optional: If you want to chroot into the newly created guest so as to install new packages, it might be a good idea to mount a few filesystems required by some packages.
 
# Optional: If you want to chroot into the newly created guest so as to install new packages, it might be a good idea to mount a few filesystems required by some packages.
 
## Bind /dev, /proc, /sys to the corresponding directories in $GuestRoot
 
## Bind /dev, /proc, /sys to the corresponding directories in $GuestRoot
 
# Modify guest configuration files to enable a smoother boot process
 
# Modify guest configuration files to enable a smoother boot process
## Modify '''/etc/inittab''' by deleting all lines that create the consoles ( agetty )
+
## Modify '''/etc/rc.shutdown''' by removing anything hardware/clock/mount related. This includes most everything under ''Saving Random Seed'.
## Modify '''/etc/rc.shutdown''' by removing anything hardware/clock/mount related. This  
+
includes most everything under ''Saving Random Seed'.
+
 
## Modify '''/etc/rc.sysinit''' by anything hardware/clock/mount related.
 
## Modify '''/etc/rc.sysinit''' by anything hardware/clock/mount related.
## Create '''/etc/init.d/rc'''
 
 
## Modify '''/etc/syslog-ng.conf''' by removing file("/proc/kmsg")
 
## Modify '''/etc/syslog-ng.conf''' by removing file("/proc/kmsg")
## Modify '''/etc/rc.conf''' by removing the networks Daemon.
 
  
===Annexe : Configuration files modified===
+
=Troubleshooting=
'''/etc/init.d/rc'''
+
==Viewing output from vserver $GuestName start / stop==
if [ $1 -eq 3 ]; then
+
echo "entering runlevel 3:multi";
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/etc/rc.multi
+
fi
+
if [ $1 -eq 6 ]; then
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echo "entering runlevel 6:reboot";
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/etc/rc.shutdown
+
fi
+
if [ $1 -eq 0 ]; then
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echo "entering runlevel 0: shutdown";
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/etc/rc.shutdown
+
fi
+
if [ $1 -eq 4 ]; then
+
echo "entering runlevel 4";
+
fi
+
if [ $1 -eq 5 ]; then
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echo "entering runlevel 5";
+
fi
+
if [ $1 -eq 1 ]; then
+
echo "entering runlevel 1:single";
+
/etc/rc.single
+
fi
+
if [ $1 -eq 2 ]; then
+
echo "entering runlevel 2:multi";
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/etc/rc.multi
+
fi
+
  
====/etc/rc.sysini====
+
'''NOTE : ''' For me, this only worked in the actual consoles, not in X.
#!/bin/bash
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#
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# /etc/rc.sysinit
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#
+
+
. /etc/rc.conf
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. /etc/rc.d/functions
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+
echo " "
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printhl "Arch Linux\n"
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printhl "${C_H2}http://www.archlinux.org"
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printhl "Copyright 2002-2007 Judd Vinet"
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printhl "Copyright 2007-2009 Aaron Griffin"
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printhl "Distributed under the GNU General Public License (GPL)"
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printsep
+
+
+
# start up our mini logger until syslog takes over
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/sbin/minilogd
+
+
if [ -x /sbin/udevadm ]; then
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stat_busy "Starting UDev Daemon"
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/sbin/udevd --daemon
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stat_done
+
else
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# Static /dev, our last resort
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status "Using static /dev filesystem" true
+
fi
+
+
# Trigger udev uevents
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if /bin/pidof -o %PPID /sbin/udevd >/dev/null; then
+
  stat_busy "Triggering UDev uevents"
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  /sbin/udevadm trigger
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  stat_done
+
fi
+
  NETFS="nonfs,nonfs4,nosmbfs,nocifs,nocodafs,noncpfs,nosysfs,noshfs,nofuse,nofuseblk,noglusterfs"
+
+
stat_busy "Mounting Local Filesystems"
+
/bin/rm -f /etc/mtab*
+
# Write /proc, /sys and /dev to /etc/mtab
+
if [ -e /proc/mounts ]; then
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/bin/grep -e "rootfs" -e "/proc " -e "/sys " -e "/dev " /proc/mounts >>    /etc/mtab
+
fi
+
stat_done
+
 
+
stat_busy "Configuring System Clock"
+
if [ ! -f /var/lib/hwclock/adjtime ]; then
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echo "0.0 0 0.0" > /var/lib/hwclock/adjtime
+
fi
+
if [ "$TIMEZONE" != "" -a -e "/usr/share/zoneinfo/$TIMEZONE" ]; then
+
/bin/rm -f /etc/localtime
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/bin/cp "/usr/share/zoneinfo/$TIMEZONE" /etc/localtime
+
fi
+
+
if [ -n "$HWCLOCK_PARAMS" ]; then
+
/sbin/hwclock --adjust #Adjust for system drift
+
/sbin/hwclock $HWCLOCK_PARAMS
+
fi
+
stat_done
+
+
RANDOM_SEED=/var/lib/misc/random-seed
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if [ -f $RANDOM_SEED ]; then
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stat_busy "Initializing Random Seed"
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/bin/cat $RANDOM_SEED > /dev/urandom
+
stat_done
+
fi
+
+
stat_busy "Removing Leftover Files"
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/bin/rm -f /etc/nologin &>/dev/null
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/bin/rm -f /etc/shutdownpid &>/dev/null
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/bin/rm -f /var/lock/* &>/dev/null
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/bin/rm -rf /tmp/* /tmp/.* &>/dev/null
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/bin/rm -f /forcefsck &>/dev/null
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(cd /var/run && /usr/bin/find . ! -type d -exec /bin/rm -f -- {} \; )
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: > /var/run/utmp
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/bin/chmod 0664 /var/run/utmp
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# Keep {x,k,g}dm happy with xorg
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/bin/mkdir /tmp/.ICE-unix && /bin/chmod 1777 /tmp/.ICE-unix
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/bin/mkdir /tmp/.X11-unix && /bin/chmod 1777 /tmp/.X11-unix
+
stat_done
+
+
#status "Updating Shared Library Links" /sbin/ldconfig
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+
if [ "$HOSTNAME" != "" ]; then
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status "Setting Hostname: $HOSTNAME" /bin/hostname $HOSTNAME
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fi
+
+
# Set the NIS domain name, if necessary
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[ -f /etc/conf.d/nisdomainname ] && . /etc/conf.d/nisdomainname
+
if [ "$NISDOMAINNAME" != "" ]; then
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status "Setting NIS Domain Name: $NISDOMAINNAME" /bin/nisdomainname  $NISDOMAINNAME
+
fi
+
+
status "Updating Module Dependencies" /sbin/depmod -A
+
+
# Flush old locale settings
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: >/etc/profile.d/locale.sh
+
/bin/chmod 755 /etc/profile.d/locale.sh
+
# Set user defined locale
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[ -z "$LOCALE" ] && LOCALE="en_US"
+
stat_busy "Setting Locale: $LOCALE"
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echo "export LANG=$LOCALE" >>/etc/profile.d/locale.sh
+
stat_done
+
  
# Adding persistent network/cdrom generated rules
+
# Make sure that the device /dev/console exists in the guest
if [ -f "/dev/.udev/tmp-rules--70-persistent-cd.rules" ]; then
+
## If it does not, cp -a /dev/console $GuestRoot/dev/
stat_busy "Adding persistent cdrom udev rules"
+
/bin/cat /dev/.udev/tmp-rules--70-persistent-cd.rules >> /etc/udev/rules.d/70-persistent-cd.rules
+
stat_done
+
fi
+
if [ -f "/dev/.udev/tmp-rules--70-persistent-net.rules" ]; then
+
stat_busy "Adding persistent network udev rules"
+
/bin/cat /dev/.udev/tmp-rules--70-persistent-net.rules >> /etc/udev/rules.d/70-persistent-net.rules
+
stat_done
+
fi
+
  
/bin/dmesg >| /var/log/dmesg.log
+
==SSH will not start==
 +
I noticed that /dev/null did not always get created properly in my first experimentations. Therefore I did a quick :
 +
# cp -a /dev/null $GuestRoot/dev
 +
# cp -a /dev/zero $GuestRoot/dev
  
# End of file
+
Furthermore, if you're not using the dummy network driver and are attaching to the host's network interface, you'll want to configure the ListenAddress statement of /etc/ssh/sshd_config so that it binds only to the guest's IP address as opposed to 127.0.0.1.
# vim: set ts=2 noet:
+
  
====/etc/rc.shutdown====
+
==SSH immediately terminates the connection==
#!/bin/bash
+
On my machine, SSH used to authenticate me correctly and log me in, but then immediately drop the connection without an explanation. Consulting /var/log/auth.log revealed the following:
#
+
# /etc/rc.shutdown
+
#
+
  
. /etc/rc.conf
+
sshd[17899]: pam_limits(sshd:session): Could not set limit for 'nice': Operation not permitted
. /etc/rc.d/functions
+
  
# avoid staircase effect
+
This is easily fixed by commenting all '''nice''' related lines in /etc/security/limits.conf.
/bin/stty onlcr
+
  
echo " "
+
=Tips & Trick=
printhl "Initiating Shutdown..."
+
==Network via dummy adapters==
echo " "
+
Here, you're either using the dummy module to create virtual network adapters or created interface aliases via /usr/sbin/ip. I went for the former and configured the host as such :
 
+
# ''/etc/sysctl.d/99-sysctl.conf'' : net.ipv4.ip_forward=1<br>
# avoid NIS hanging syslog-ng on shutdown by unsetting the domainname
+
Modify or add that statement to enable routing on the host
if [ -x /bin/domainname ]; then
+
# ''/etc/rc.local''<br>
/bin/domainname ""
+
modprobe dummy numdummies=$NumberOfGuests<br>
fi
+
ip link set dev dummy$GuestContext name $GuestName
 
+
if [ -x /etc/rc.local.shutdown ]; then
+
/etc/rc.local.shutdown
+
fi
+
 
+
if [ "$PREVLEVEL" = "3" -o "$PREVLEVEL" = "5" ]; then
+
# Find daemons NOT in the DAEMONS array. Shut these down first
+
if [ -d /var/run/daemons ]; then
+
for daemon in $(/bin/ls -1t /var/run/daemons); do
+
  if ! in_array $daemon ${DAEMONS[@]}; then
+
stop_daemon $daemon
+
  fi
+
done
+
fi
+
# Shutdown daemons in reverse order
+
let i=${#DAEMONS[@]}-1
+
while [ $i -ge 0 ]; do
+
if [ "${DAEMONS[$i]:0:1}" != '!' ]; then
+
ck_daemon ${DAEMONS[$i]#@} || stop_daemon ${DAEMONS[$i]#@}
+
fi
+
        let i=i-1
+
    done
+
fi
+
 
+
# Terminate all processes
+
stat_busy "Sending SIGTERM To Processes"
+
/sbin/killall5 -15 &> /dev/null
+
/bin/sleep 5
+
stat_done
+
 
+
stat_busy "Sending SIGKILL To Processes"
+
/sbin/killall5 -9 &> /dev/null
+
/bin/sleep 1
+
stat_done
+
 
+
# Write to wtmp file before unmounting
+
/sbin/halt -w
+
 
+
# Power off or reboot
+
if [ "$RUNLEVEL" = "0" ]; then
+
printsep
+
    printhl "${C_H2}POWER OFF"
+
/sbin/poweroff -d -f -h -i
+
else
+
printsep
+
printhl "${C_H2}REBOOTING"
+
# if kexec is installed and a kernel is loaded, use it
+
[ -x /sbin/kexec ] && /sbin/kexec -e > /dev/null 2>&1
+
/sbin/reboot -d -f -i
+
fi
+
 
+
# End of file
+
# vim: set ts=2 sw=2 noet:
+
 
+
 
+
 
+
=Troubleshooting=
+
  
=Tips & Tricks=
+
This provides me with dummy interfaces that I can route / firewall that are all named the same as my guests... yay.
  
 
=More Resources=
 
=More Resources=
[http://linux-vserver.org/Problematic_Programs Problematic Programs]
+
[http://linux-vserver.org/Problematic_Programs Problematic Programs]<br>
[http://linux-vserver.org/Howto_make_bsd-style_init_sysv-compatible Make BSD style init SYSV compatible]
+
[http://linux-vserver.org/Howto_make_bsd-style_init_sysv-compatible Make BSD style init SYSV compatible]<br>
[http://www.cedarcreeksoftware.com/an-even-easier-linux-vserver-tutorial.html Vserver tutorial]
+
[http://www.cedarcreeksoftware.com/an-even-easier-linux-vserver-tutorial.html Vserver tutorial]<br>
[http://linux-vserver.org/Installation_on_ArchLinux linux-vserver.org's Installation on ArchLinux]
+
[http://linux-vserver.org/Installation_on_ArchLinux linux-vserver.org's Installation on ArchLinux]<br>
[http://wiki.linux-vserver.org/Networking_vserver_guests linux-verserver.org's networking tutorial]
+
[http://wiki.linux-vserver.org/Networking_vserver_guests linux-verserver.org's networking tutorial]<br>
 
<!-- vim: set ft=Wikipedia: -->
 
<!-- vim: set ft=Wikipedia: -->

Revision as of 09:58, 24 September 2013

This article aims to provide all necessary information regarding the creation of a vserver host as well as vserver guests running Arch Linux. This will enable you to setup virtual servers that provide different services as if they were on different machines, with a very little overhead. You can get more information about virtual servers here.

Preparing the Host

To prepare the vserver host environment, you will need to install both a vserver patched kernel, the vserver utilities and their dependencies which are located in the AUR. The required packages are dietlibcAUR, beecryptAUR, kernel26-vserverAUR (not found or linux-vserverAUR orphan), and util-vserverAUR

Paths of Interest

/etc/vservers : configuration root ( reference )

/etc/vservers/.defaults : configuration skeleton used when building new guests
/etc/vservers/.defaults/vdirbase : symlink to the folder containing vserver guests. This defaults to /vservers.
/etc/vservers/<guest name> : guest specific configurations

Preparing the Guests

Vserver will launch guests from subfolders of /etc/vservers/.defaults/vdirbase. As such, creating a new guest system is as simple as installing the required packages in a folder of the host. Furthermore, there's nothing stopping you ( and quite a few things encouraging you ) to mount filesystems to the subfolders of vdirbase and installing your guest in there.

If you plan on doing this often, I highly recommend that you write yourself a little batch script since most of these steps can be automated quite easily.

Preparing the guest installation media

NOTE : This is all heavily inspired from Install From Existing Linux and will therefore be quite brief when not mentioning Vserver specific steps.

Optional: Base variables to follow along with the steps

GuestName= # Name of the guest
GuestRoot=/etc/vservers/.defaults/vdirbase/$GuestName
GuestPackages= # Listing of packages to install via pacman
GuestDisk= # Installation target device
GuestNetDevice= # ex.: eth0, dummy0, etc...
GuestIP= # I think you get it
GuestContext= # Unique identifier for the guest, I go with the last part of the IP

Optional: Preparing the guest disk

  1. Create a LVM Physical Volume, a Volume Group and a Logical Volume ( wiki:LVM )
  2. Create a filesystem on the lvm volume
  3. mkdir $GuestRoot
  4. mount /dev/$GuestDisk $GuestRoot

Optional: Link the host and guest pacman cache

  1. mkdir $GuestRoot/var/cache/pacman/pkg
  2. mount -o bind /var/cache/pacman/pkg $GuestRoot/var/cache/pacman/pkg

Prepare Vserver

  1. vserver $GuestName -m skeleton --context $GuestContext --interface $GuestNetDevice:$GuestIP --flags lock,virt_mem,virt_uptime,virt_cpu,virt_load,sched_hard,hide_netif --initstyle plain
  2. (optional) cd /etc/vservers/$GuestName/interfaces
  3. (optional) cp -r 0 1
  4. (optional) echo 'lo' > dev
  5. (optional) echo '127.0.0.$GuestContext' > ip

Prepare the guest's filesystem

  1. Prepare guest filesystem for the pacman db
    1. mkdir -p /newarch/var/lib/pacman

Install the base system

NOTE : To save some time, it's probably a good idea to create a text file containing all the packages to install and call it via "pacman -S `cat $GuestPackages` -r $GuestRoot" instead of the following :

  1. pacman -S base -r $GuestRoot
  2. Optional: If you want to chroot into the newly created guest so as to install new packages, it might be a good idea to mount a few filesystems required by some packages.
    1. Bind /dev, /proc, /sys to the corresponding directories in $GuestRoot
  3. Modify guest configuration files to enable a smoother boot process
    1. Modify /etc/rc.shutdown by removing anything hardware/clock/mount related. This includes most everything under Saving Random Seed'.
    2. Modify /etc/rc.sysinit by anything hardware/clock/mount related.
    3. Modify /etc/syslog-ng.conf by removing file("/proc/kmsg")

Troubleshooting

Viewing output from vserver $GuestName start / stop

NOTE : For me, this only worked in the actual consoles, not in X.

  1. Make sure that the device /dev/console exists in the guest
    1. If it does not, cp -a /dev/console $GuestRoot/dev/

SSH will not start

I noticed that /dev/null did not always get created properly in my first experimentations. Therefore I did a quick :

  1. cp -a /dev/null $GuestRoot/dev
  2. cp -a /dev/zero $GuestRoot/dev

Furthermore, if you're not using the dummy network driver and are attaching to the host's network interface, you'll want to configure the ListenAddress statement of /etc/ssh/sshd_config so that it binds only to the guest's IP address as opposed to 127.0.0.1.

SSH immediately terminates the connection

On my machine, SSH used to authenticate me correctly and log me in, but then immediately drop the connection without an explanation. Consulting /var/log/auth.log revealed the following:

sshd[17899]: pam_limits(sshd:session): Could not set limit for 'nice': Operation not permitted

This is easily fixed by commenting all nice related lines in /etc/security/limits.conf.

Tips & Trick

Network via dummy adapters

Here, you're either using the dummy module to create virtual network adapters or created interface aliases via /usr/sbin/ip. I went for the former and configured the host as such :

  1. /etc/sysctl.d/99-sysctl.conf : net.ipv4.ip_forward=1

Modify or add that statement to enable routing on the host

  1. /etc/rc.local
modprobe dummy numdummies=$NumberOfGuests
ip link set dev dummy$GuestContext name $GuestName

This provides me with dummy interfaces that I can route / firewall that are all named the same as my guests... yay.

More Resources

Problematic Programs
Make BSD style init SYSV compatible
Vserver tutorial
linux-vserver.org's Installation on ArchLinux
linux-verserver.org's networking tutorial