Installation on Gentoo

From Linux-VServer

Revision as of 16:57, 4 November 2009 by Dmartin (Talk | contribs)

Jump to: navigation, search


Host configuration

Install a Linux-VServer kernel

Installing a prepatched kernel is as easy as:

# emerge vserver-sources

After the vserver-sources are installed it's time to configure them using make menuconfig. Below is a common configuration for 2.1.1 and above. If you are using 2.0.x some configuration options may not be present.

# cd /usr/src/linux-<KERNELVERSION>-vserver-<VSERVERVERSION>
# make menuconfig

Linux VServer --->
  [ ] Enable Legacy Kernel API
  [ ] Enable Legacy Networking Kernel API
  [ ] Remap Source IP Address
  [*] Enable COW Immutable Link Breaking
  [*] Enable Virtualized Guest Time
  [*] Enable Proc Security
  [*] Enable Hard CPU Limits
  [*]   Avoid idle CPUs by skipping Time
  [*]   Limit the IDLE task
      Persistent Inode Tagging (UID24/GID24)  --->
  [ ] Tag NFSD User Auth and Files
  [ ] Enable Inode Tag Propagation
  [*] Honor Privacy Aspects of Guests
  [ ] VServer Debugging Code

Note: If you are using reiserfs as file system on the partition where guest images are stored, you will need to enable extended attributes for reiserfs in your kernel configuration and additionally add the attrs option in /etc/fstab.

File systems  --->
  <*> Reiserfs support
  [*]   ReiserFS extended attributes
/dev/hdb1 /vservers reiserfs noatime,attrs 0 0

After you've built and installed the kernel, update your boot loader and finally reboot to see if the kernel boots correctly.

(Building the kernel)
# make
# make modules_install
# cp arch/<arch>/boot/bzImage /boot/kernel-<KERNELVERSION>-vserver-<VSERVERVERSION>
(Edit bootloader config file as required and)
# reboot

Setup host environment

To maintain your virtual servers you need the util-vserver package which contains all necessary programs and many useful features.

# emerge >=sys-cluster/util-vserver-0.30.212

You have to run the vprocunhide command after every reboot in order to setup /proc permissions correctly for vserver use. An init script has been installed by util-vserver. To use it you should add it to a runlevel:

# rc-update add vprocunhide default
# /etc/init.d/vprocunhide start
# rc-update add util-vserver default
# /etc/init.d/util-vserver start

Guest creation

Download a precompiled stage3

Since many hardware related commands are not available inside a virtual server, there has been a patched version of baselayout known as baselayout-vserver. However, since baselayout-2/openrc, all required changes have been integrated, eliminating the need for separate vserver stages, profiles and baselayout. The only (temporary) drawback is that baselayout-2/openrc is still in testing (~arch) and there are no stages with baselayout-2/openrc available on the mirrors yet.

As soon as baselayout-2/openrc is stable you can use a precompiled stage3 from one of the Gentoo mirrors. In the meantime please download a stage3 or gentoo-vserver stage from here. Since a stage3 contains a complete root file system you can use the template build method of util-vserver. However, this method only works reliable since util-vserver-0.30.213_rc5, so make sure you have the right version installed.

You have to choose a context ID for your vserver (dynamic context IDs are discouraged) as well as the necessary network device information (In this example eth0 is configured with and the context ID is equivalent to the last two parts of the virtual servers IP).

Using the template build method

For a long time now, plain init style was the only init style available for gentoo, i.e. a normal init process will be started inside the guest, just like on any common Unix system. However this approach has some drawbacks:

  • No possibility to see output of init/rc scripts
  • Wasted resources for idle init processes in each guest
  • Annoying conflicts for /etc/inittab

Therefore, many users have requested the gentoo init style to be reimplemented, which has been abandoned since it was a very hacky implementation and more or less worked by accident due to other modifications done to baselayout back then. However, as of util-vserver-0.30.212 the gentoo init style has been reimplemented in a concise manner and will become the default in the future.

# vserver myguest build \
  --context 1253 \
  --hostname myguest \
  --interface eth0: \
  --initstyle gentoo \
  -m template -- \
    -t /path/to/gentoo-vserver-<arch>-<version>.tar.bz2 \
    -d gentoo

You should be able to start and enter the vserver by using the commands below.

# vserver myguest start

   OpenRC 0.4.3 is starting up Gentoo Linux (x86_64) [VSERVER]

Press I to enter interactive boot mode

* /proc is already mounted, skipping
* Setting hostname to myguest...                     [ ok ]
* Creating user login records...                     [ ok ]
* Cleaning /var/run...                               [ ok ]
* Wiping /tmp directory...                           [ ok ]
* Updating /etc/mtab...                              [ ok ]
* Initializing random number generator...            [ ok ]
* Starting syslog-ng...                              [ ok ]
* Starting fcron...                                  [ ok ]
* Starting Name Service Cache Daemon...              [ ok ]
* Starting local...                                  [ ok ]
# vserver-stat
0       90   1.4G 153.4K  14m00s11   6m45s17   2h59m59 root server
1253     2     3M   286    0m00s45   0m00s42   0m02s91 myguest
# vserver myguest enter
# ps ax
    1 ?        Ss     0:04 init [3]
27637 ?        Ss     0:00 /usr/sbin/syslog-ng
27656 ?        Ss     0:00 /usr/sbin/fcron -c /etc/fcron/fcron.conf
27676 ?        Ssl    0:00 /usr/sbin/nscd
27713 ?        S+     0:00 login
27737 pts/15   Ss     0:00 /bin/bash
27832 pts/15   R+     0:00 ps ax
# logout

Maintenance made easy

Start guests on boot

You can start certain guests during boot. Each guest can be assigned a MARK. Now everything you have to do is configure these MARKs in the guests configuration and tell the init script to run all MARKed guests.

(Do this for every guest you want to start)
# mkdir -p /etc/vservers/myguest/apps/init
# echo "default" > /etc/vservers/myguest/apps/init/mark

Note: Since all guests marked with "default" are started by default, nothing more has to be done. If you have different marks you should also update /etc/conf.d/vservers.

Keep portage in sync

The script vesync will help you to keep the metadata cache and overlays in sync. vemerge is a simple wrapper for emerge in guests.

(Sync metadata for 'myguest')
# vesync myguest
(Sync metadata for all guests)
# vesync -a
(Sync metadata for all guests except 'myguest')
# vesync -a -e myguest
(Sync 'myoverlay' for all guests)
# vesync -a \
  --overlay /usr/local/overlays/myoverlay \
  --overlay-host rsync:// \
(emerge app-editors/vim in 'myguest')
# vemerge myguest -- app-editors/vim -va

Update guests

Gentoo guests can share packages to save compilation time. In order to use shared packages, you have to create a central directory for packages on the host. We will use /var/cache/vpackages on the host and mount it to /usr/portage/packages in every guest.

# mkdir -p /var/cache/vpackages
# $EDITOR /etc/vservers/myguest/fstab
(Add this line at the end)
/var/cache/vpackages /usr/portage/packages none bind,rw 0 0

Now you can use vupdateworld to update every guest. The command is equivalent to something like emerge --deep --update --newuse world depending on command line options.

(Pretend update for 'myguest')
# vupdateworld -p myguest
(Update 'myguest' using binary packages)
# vupdateworld -k myguest
(Update all guests using binary packages)
# vupdateworld -ka

Note: In order to get binary packages you can either use PORTAGE_BINHOST (see man make.conf) or set FEATURES="buildpkg" in one or more guests.

After a successful update you can easily update all configuration files with vdispatch-conf. It is a simple wrapper for dispatch-conf and behaves exactly the same.

(Update configuration files for 'myguest')
# vdispatch-conf myguest
(Update configuration files for all guests)
# vdispatch-conf -a

Bash scripts

These scripts will hopefully help some of you out with some basic tasks. Review each script carefully, so you know what it is doing.

The scripts here were outdated and the original contributor removed them.

External Resources

Please take a look at the Gentoo Linux-VServer Howto for more information. In general we try to keep the wiki in sync, nevertheless it might help :)

Personal tools