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Dobrica Pavlinušić's random unstructured stuff
OpenVZ
OpenVZ is nice name-space virtualization, creating chroot jails on steroids, similar in spirit to Solaris zones. It ideal if you want to run single kernel and allocate resources using bean counters as opposed to hard-limits (20% of CPU as opposed to one core). Each slice is called VE.
Disk speed
dpavlin@zut:~$ sudo hdparm -tT /dev/cciss/c1d0 /dev/sda
/dev/cciss/c1d0:
Timing cached reads: 2184 MB in 2.00 seconds = 1092.39 MB/sec
Timing buffered disk reads: 324 MB in 3.02 seconds = 107.40 MB/sec
/dev/sda:
Timing cached reads: 2144 MB in 2.00 seconds = 1071.89 MB/sec
Timing buffered disk reads: 136 MB in 3.02 seconds = 45.02 MB/sec
Insert joke about enterprise storage
Add disk space to VE
We are using normal Linux LVM with single logical volume for all VEs.
First, resize logical volume:
root@koha-hw:~# vgextend -L +80G /dev/vg/vz
vgextend: invalid option -- L
Error during parsing of command line.
root@koha-hw:~# lvextend -L +80G /dev/vg/vz
Extending logical volume vz to 100.00 GB
Logical volume vz successfully resized
root@koha-hw:~# resize2fs /dev/vg/vz
resize2fs 1.40-WIP (14-Nov-2006)
Filesystem at /dev/vg/vz is mounted on /vz; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 7
Performing an on-line resize of /dev/vg/vz to 26214400 (4k) blocks.
The filesystem on /dev/vg/vz is now 26214400 blocks long.
root@koha-hw:~# df -h /vz/
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg-vz 99G 20G 79G 21% /vz
Then, take a look how much space does VEs take:
root@koha-hw:~# vzlist -o veid,diskspace,diskspace.s,diskspace.h,diskinodes,diskinodes.s,diskspace.h
VEID DQBLOCKS DQBLOCKS.S DQBLOCKS.H DQINODES DQINODES.S DQBLOCKS.H
212052 11717220 15728640 20971520 61001 286527 20971520
212226 6407804 10485760 12582912 69011 435472 12582912
alternativly, you can also execute df inside VEs:
root@koha-hw:~# vzlist -o veid -H | xargs -i sh -c "echo --{}-- ; vzctl exec {} df -h"
--212052--
Filesystem Size Used Avail Use% Mounted on
simfs 15G 12G 3.9G 75% /
tmpfs 2.0G 0 2.0G 0% /lib/init/rw
tmpfs 2.0G 0 2.0G 0% /dev/shm
--212226--
Filesystem Size Used Avail Use% Mounted on
simfs 10G 6.2G 3.9G 62% /
tmpfs 2.0G 0 2.0G 0% /lib/init/rw
tmpfs 2.0G 0 2.0G 0% /dev/shm
next, we will set diskpace on both VEs (becase we want them to share all available resources) to new logical volume size:
root@koha-hw:~# vzlist -o veid -H | xargs -i vzctl set {} --diskspace 100G:100G --save
Saved parameters for VE 212052
Saved parameters for VE 212226
This VEs are not in production, and one is development version of another. When we move to production, we want to enforce more strict limit on disk usage, to protect production machine from running out of disk space in case the development one goes wild.
VE management
We usually want to do some operations on bunch of VEs at once. This can be done using vzctl exec in one sweep like this:
Update Debian
vzlist -H -o veid | xargs -i vzctl exec {} 'apt-get update && apt-get -y upgrade' 2>&1 | tee ~/log
Quick reporting
You can read more about groupby.pl and sum.pl on my blog.
# install dependencies which are not part of standard lenny (sorry!)
cpanp i IPC::System::Simple
dpavlin@mjesec:~$ vzps -E axv --no-headers \
| groupby.pl 'sum:($7+$8+$9*1024),1,count:1' --join 'sudo vzlist -H -o veid,hostname' --on 2 \
| sort -rn | align | sum.pl -h
webgui.rot13.org 23 1026M OOOOOOOOOOOO 1026M
0 385 855M OOOOOOOOOO------------ 1882M
saturn.ffzg.hr 32 544M OOOOOO----------------------- 2427M
eprints.ffzg.hr 18 351M OOOO----------------------------- 2778M
arh.rot13.org 20 224M OO---------------------------------- 3003M
find getty processes
root@mljac:~# ps ax | grep getty | cut -c-5 | xargs vzpid
Pid VEID Name
5668 0 getty
5670 0 getty
5672 0 getty
5673 0 getty
5674 0 getty
5675 0 getty
9503 207016 getty
9504 207013 getty
9505 207013 getty
9534 207016 getty
9535 207015 getty
9536 207013 getty
9537 207013 getty
9538 207015 getty
9539 207015 getty
9540 207015 getty
9541 207016 getty
9542 207015 getty
9543 207016 getty
9545 207013 getty
9546 207013 getty
9547 207015 getty
9548 207016 getty
devices inside VE
For example, fuse
dpavlin@brr:/dev$ vzctl set 100 --devices c:10:229:rw --save
Links
Suite of perl scripts in spirit of xen-tools but for OpenVZ
Installation
Install perl dependencies from Debian packages
This step is optional. If you don't want to use perl modules from packages provided by your distribution, skip this step, and modules will be automatically installed in next one.
sudo apt-get install libio-prompt-perl libregexp-common-perl libdata-dump-perl
Install utilities from Debian packages
sudo apt-get install host
Checkout source
svn co svn://svn.rot13.org/vz-tools/trunk vz-tools
Check and install perl modules from CPAN
cd vz-tools
perl Makefile.PL
make
Please note that there is no need to run make install
Tools are runnable from current directory. This will probably change in later versions.
Usage
This is quick hand-on overview of commands to get you started.
All commands must be started with root priviledges
vz-create.pl
This will perform following steps:
- Create new virtual machine bootstraped using debootstrap
- Change root password
- Create single user
- Make small custimization like installing vim and apt-iselect
All commands will be echoed on screen, even passwords. However, if you want to learn steps in creating OpenVZ VE, this is very helpful.
To run interactive session which asks questions use:
./vz-create.pl
Other alternative is to just enter hostname (defined in /etc/hosts for example)
./vz-create.pl my-new-ve.exmple.com
or by specifing IP adress
./vz-create.pl 192.168.42.42
vz-optimize.pl
vz-clone.pl
root@black:~/vz-tools# time ./vz-clone.pl create 1001
Clone VE 1001 -> 101001
found LV /dev/vg/vz for /vz
vzquota : (warning) Quota is running, so data reported from quota file may not reflect current values
quota for 1001 | 10485760 < 20971520 | usage: 7826792
using existing /dev/vg/vz-clone-101001
Mounting /dev/vg/vz-clone-101001 to /tmp/vz-clone-101001
rsync /vz/private/1001 -> /tmp/vz-clone-101001/private
101001 new IP number: 10.42.42.42
101001 new hostname: clone-42.example.com
Please review config file: /etc/vz/conf/101001.conf
Add NAT for new VE with: iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
Start clone of 1001 with: vzctl start 101001
real 1m57.347s
user 0m2.252s
sys 0m8.591s
Source
Related posts on my blog
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