VS Quota HowTo
How to use Quota Support for VS
Quota on a separate partition (LVM, Conv. Quota)
This is an example for setting up quota support for a VServer based
system. It tries to explain how to setup user/group quota on a separate
partition. If you want to use context quota support on a shared partition,
have a look at the
Context Quota HowTo.
The following walkthrough was done on a Mandrake 8.2 Linux system,
running a custom built 2.4.20rc1 kernel, patched with CTX-14 patches
from the 0.21 release of VServer. Packages installed: 0.21 vserver
base/admin, quota-tools 3.07.
In this example, /dev/vg is the LVM volume group providing the
separate partition /dev/vg/part1 for the to-be-moved virtual
server TE01.
- Prerequisites
You will require at least the following to use/enable quota
support on your system:- quota support for the filesystem you want to use.
- a patched kernel (quota, vserver, lvm?)
- the quota-tools compiled for this kernel.
- a free partition, the size for one virtual server.
- a good idea what quota is, and how to use the tools.
- Required Modifications
There are no special modifications required, but I would
strongly suggest to modify the vserver script with the
following patch, to leave the directory before executing
the post-stop script ...----------------- patch me ----------------- --- /usr/sbin/vserver Fri Nov 8 21:21:43 2002 +++ /usr/sbin/vserver.patched Fri Nov 8 21:21:30 2002 @@ -500,6 +500,7 @@ # We umount anyway, because "enter" establish the mount # but when you exit, the server is considered not running umountproc /vservers/$1 + cd / test -x /etc/vservers/$1.sh && /etc/vservers/$1.sh post-stop $1 ifconfig_iproot_off $1 elif [ "$2" = "restart" ] ; then ----------------- patch me -----------------
- Server Setup/Move
This step assumes that you want to move your existing virtual
server TE01 on a separate partition /dev/vg/part1, and enable
quota support for that partition. If you either do not have an
existing server or already moved/created one on a separate
partition, you have to adjust and/or leave out the appropriate
steps.- stop the virtual server
# vserver TE01 stop
- create filesystem and mountpoint
# mke2fs -j /dev/vg/part1 # mkdir /vservers/LV01 # mount /dev/vg/part1 /vservers/LV01
- copy the virtual server and the configuration
# cp -a /vservers/TE01/. /vservers/LV01/ # cp -a /etc/vservers/TE01.conf /etc/vservers/LV01.conf
- create/modify the start/stop scripts
----------------- /etc/vservers/LV01.sh ----------------- #!/bin/sh case $1 in pre-start) e2fsck -p /dev/vg/part1 mount /dev/vg/part1 /vservers/LV01 rm -f /vservers/LV01/dev/hdv1 cp -fa /dev/vg/part1 /vservers/LV01/dev/hdv1 ;; post-start) ;; pre-stop) ;; post-stop) mount -o remount,ro /vservers/LV01 umount /vservers/LV01 ;; *) echo $0 pre-start echo $0 pre-stop echo $0 post-start echo $0 post-stop ;; esac ----------------- /etc/vservers/LV01.sh -----------------
- change the server mtab file
/dev/hdv1 / ext3 rw,usrquota,grpquota 0 0
- if not already done, install the quota-tools for the virtual server
# vrpm LV01 -- -i quota-3.07-1.i586.rpm
- start the server and change into it
# vserver LV01 start # vserver LV01 enter
- run the quotacheck tool
# quotacheck -maug
- take a look at the quota report
# repquota -aug *** Report for user quotas on device /dev/hdv1 Block grace time: 7days; Inode grace time: 7days Block limits File limits User used soft hard grace used soft hard grace ---------------------------------------------------------------- root -- 249712 0 0 12146 0 0 rpm -- 13124 0 0 71 0 0 apache -- 980 0 0 235 0 0 rpcuser -- 4 0 0 1 0 0 *** Report for group quotas on device /dev/hdv1 Block grace time: 7days; Inode grace time: 7days Block limits File limits Group used soft hard grace used soft hard grace ---------------------------------------------------------------- root -- 248964 0 0 12102 0 0 daemon -- 4 0 0 1 0 0 tty -- 16 0 0 2 0 0 ... - live happily ever after using quota wisely ...
- stop the virtual server
- Advantages and Disadvantages
This approach gives you several advantages and has some
drawbacks and security hazards.Advantages are:- no need to modify tools or kernel regarding quota.
- fixed maximum hard limit for each virtual server.
- no security/access issues with files or partitions.
- all quota settings can be done within the server.
Disadvantages would/could be:
- no unification across servers is possible.
- changing the maximum size requires fs/partition resize.
- filesystem caching is done for each partition.
Security issues !!! (so far):
- direct block device access to the partition.
this has several implications ...- root can modify/replace the root filesystem at low levels.
- root can create arbitrary device nodes, gaining access
to any physical resource. - wiping out the mounted (root) filesystem will probably
harm the kernel.
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| ©2002 Herbert Pötzl |