Difference between revisions of "Arch VServer"

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[[Category:Virtualization]]
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#REDIRECT [[Virtual Private Server]]
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].
 
 
 
=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 {{AUR|dietlibc}}, {{AUR|beecrypt}}, {{AUR|kernel26-vserver}} (not found or {{AUR|linux-vserver}} orphan), and {{AUR|util-vserver}}
 
 
 
=Paths of Interest=
 
 
 
'''/etc/vservers''' : configuration root ( [http://www.nongnu.org/util-vserver/doc/conf/configuration.html ''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 [https://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.
 
 
 
===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===
 
# 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
 
# mkdir $GuestRoot
 
# mount /dev/$GuestDisk $GuestRoot
 
 
 
===Optional: Link the host and guest pacman cache===
 
# mkdir $GuestRoot/var/cache/pacman/pkg
 
# mount -o bind /var/cache/pacman/pkg $GuestRoot/var/cache/pacman/pkg
 
 
 
===Prepare Vserver===
 
# 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
 
# (optional) cd /etc/vservers/$GuestName/interfaces
 
# (optional) cp -r 0 1
 
# (optional) echo 'lo' > dev
 
# (optional) echo '127.0.0.$GuestContext' > ip
 
 
 
===Prepare the guest's filesystem===
 
# Prepare guest filesystem for the pacman db
 
## 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 :
 
# 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.
 
## Bind /dev, /proc, /sys to the corresponding directories in $GuestRoot
 
# 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.sysinit''' by anything hardware/clock/mount related.
 
## Create '''/etc/init.d/rc'''
 
## Modify '''/etc/syslog-ng.conf''' by removing file("/proc/kmsg")
 
## Modify '''/etc/rc.conf''' by removing the networks Daemon.
 
# Ensure '''/etc/rc.*''' can be executed: "chmod +x /etc/rc.*"
 
 
 
===Annexe : Configuration files modified===
 
'''/etc/init.d/rc'''
 
if [ $1 -eq 3 ]; then
 
echo "entering runlevel 3:multi";
 
/etc/rc.multi
 
fi
 
if [ $1 -eq 6 ]; then
 
echo "entering runlevel 6:reboot";
 
/etc/rc.shutdown
 
fi
 
if [ $1 -eq 0 ]; then
 
echo "entering runlevel 0: shutdown";
 
/etc/rc.shutdown
 
fi
 
if [ $1 -eq 4 ]; then
 
echo "entering runlevel 4";
 
fi
 
if [ $1 -eq 5 ]; then
 
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";
 
/etc/rc.multi
 
fi
 
 
 
====/etc/rc.sysinit====
 
#!/bin/bash
 
#
 
# /etc/rc.sysinit
 
#
 
 
. /etc/rc.conf
 
. /etc/rc.d/functions
 
 
echo " "
 
printhl "Arch Linux\n"
 
printhl "${C_H2}https://www.archlinux.org"
 
printhl "Copyright 2002-2007 Judd Vinet"
 
printhl "Copyright 2007-2009 Aaron Griffin"
 
printhl "Distributed under the GNU General Public License (GPL)"
 
printsep
 
 
 
# start up our mini logger until syslog takes over
 
/sbin/minilogd
 
 
if [ -x /sbin/udevadm ]; then
 
stat_busy "Starting UDev Daemon"
 
/sbin/udevd --daemon
 
stat_done
 
else
 
# Static /dev, our last resort
 
status "Using static /dev filesystem" true
 
fi
 
 
# Trigger udev uevents
 
if /bin/pidof -o %PPID /sbin/udevd >/dev/null; then
 
  stat_busy "Triggering UDev uevents"
 
  /sbin/udevadm trigger
 
  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
 
/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
 
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
 
/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
 
if [ -f $RANDOM_SEED ]; then
 
stat_busy "Initializing Random Seed"
 
/bin/cat $RANDOM_SEED > /dev/urandom
 
stat_done
 
fi
 
 
stat_busy "Removing Leftover Files"
 
/bin/rm -f /etc/nologin &>/dev/null
 
/bin/rm -f /etc/shutdownpid &>/dev/null
 
/bin/rm -f /var/lock/* &>/dev/null
 
/bin/rm -rf /tmp/* /tmp/.* &>/dev/null
 
/bin/rm -f /forcefsck &>/dev/null
 
(cd /var/run && /usr/bin/find . ! -type d -exec /bin/rm -f -- {} \; )
 
: > /var/run/utmp
 
/bin/chmod 0664 /var/run/utmp
 
# Keep {x,k,g}dm happy with xorg
 
/bin/mkdir /tmp/.ICE-unix && /bin/chmod 1777 /tmp/.ICE-unix
 
/bin/mkdir /tmp/.X11-unix && /bin/chmod 1777 /tmp/.X11-unix
 
stat_done
 
 
#status "Updating Shared Library Links" /sbin/ldconfig
 
 
if [ "$HOSTNAME" != "" ]; then
 
status "Setting Hostname: $HOSTNAME" /bin/hostname $HOSTNAME
 
fi
 
 
# Set the NIS domain name, if necessary
 
[ -f /etc/conf.d/nisdomainname ] && . /etc/conf.d/nisdomainname
 
if [ "$NISDOMAINNAME" != "" ]; then
 
status "Setting NIS Domain Name: $NISDOMAINNAME" /bin/nisdomainname  $NISDOMAINNAME
 
fi
 
 
status "Updating Module Dependencies" /sbin/depmod -A
 
 
# Flush old locale settings
 
: >/etc/profile.d/locale.sh
 
/bin/chmod 755 /etc/profile.d/locale.sh
 
# Set user defined locale
 
[ -z "$LOCALE" ] && LOCALE="en_US"
 
stat_busy "Setting Locale: $LOCALE"
 
echo "export LANG=$LOCALE" >>/etc/profile.d/locale.sh
 
stat_done
 
 
# Adding persistent network/cdrom generated rules
 
if [ -f "/dev/.udev/tmp-rules--70-persistent-cd.rules" ]; then
 
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
 
 
# End of file
 
# vim: set ts=2 noet:
 
 
 
====/etc/rc.shutdown====
 
#!/bin/bash
 
#
 
# /etc/rc.shutdown
 
#
 
 
. /etc/rc.conf
 
. /etc/rc.d/functions
 
 
# avoid staircase effect
 
/bin/stty onlcr
 
 
echo " "
 
printhl "Initiating Shutdown..."
 
echo " "
 
 
# avoid NIS hanging syslog-ng on shutdown by unsetting the domainname
 
if [ -x /bin/domainname ]; then
 
/bin/domainname ""
 
fi
 
 
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=
 
==Viewing output from vserver $GuestName start / stop==
 
 
 
'''NOTE : ''' For me, this only worked in the actual consoles, not in X.
 
 
 
# Make sure that the device /dev/console exists in the guest
 
## 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 :
 
# cp -a /dev/null $GuestRoot/dev
 
# 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 or /usr/sbin/ifconfig. I went for the former and configured the host as such :
 
# ''/etc/sysctl.conf'' : net.ipv4.ip_forward=1<br>
 
Modify or add that statement to enable routing on the host
 
# ''/etc/rc.local''<br>
 
modprobe dummy numdummies=$NumberOfGuests<br>
 
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=
 
[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]<br>
 
[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]<br>
 
[http://wiki.linux-vserver.org/Networking_vserver_guests linux-verserver.org's networking tutorial]<br>
 
<!-- vim: set ft=Wikipedia: -->
 

Latest revision as of 02:15, 6 June 2015