Demo scripts
The following demo scripts (scenarios) can be used to show advantages of OpenVZ.
Contents
Full container lifecycle
Create a container, set an IP, start, add a user, enter, exec, show
ps -axf output inside the container, stop, and destroy.
It should take about two minutes ("compare that to a time you need
to deploy a new (non-virtual) server!"). During the demonstration,
describe what's happening and why.
Here are the example commands needed:
# CT=123 # IP=10.1.1.123 # sed -i "/$IP /d" ~/.ssh/ # time vzctl create $CT --ostemplate fedora-core-5-i386-default # vzctl set $CT --ipadd $IP --hostname newCT --save # vzctl start $CT # vzctl exec $CT ps axf # vzctl set $CT --userpasswd guest:secret --save # ssh guest@$IP [newCT]# ps axf [newCT]# logout # vzctl stop $CT # vzctl destroy $CT
Massive container creation
Create/start 50 or 100 containers in a shell loop. Shows fast deployment and high density.
Here are the example commands needed:
# time for ((CT=200; CT<250; CT++)); do \ > time vzctl create $CT --ostemplate fedora-core-9-i386; \ > vzctl start $CT; \ > done
Massive container load
Use containers from the previous item — load those by ab or
http_load. This demo shows that multiple containers are working
just fine, with low response time etc.
# for ((CT=200; CT<250; CT++)); do \ > vzctl set $CT --ipadd 10.1.1.$CT --save; \ > done
On another machine:
# rpm -ihv http_load #
FIXME: http_load commands
Live migration
If you have two boxes, do vzmigrate --online from one box
to another. You can use, say, xvnc in a container and
vncclient to connect to it, then run
xscreensaver-demo, choose a suitable screensaver (eye-candy but
not too CPU aggressive) and while the picture is moving start a live
migration. You'll see that xscreensaver stalls for a few
seconds but then continues to run — on another machine! That looks amazing,
to say at least.
FIXME: commands, setup, VNC template.
Resource management
Below scenarios aims to show how OpenVZ resource management works.
UBC protection
fork() bomb
# while [ true ]; do \ > while [ true ]; do \ > echo " " > /dev/null; > done & > done
We can see that the number of processes inside container will not be growing.
We will see only the increase of numproc and/or
kmemsize fail counters in /proc/user_beancounters.
dentry cache eat up
FIXME
CPU scheduler
|
Warning: CPU weights only works in stable kernels. |
Create 3 containers:
# vzctl create 101 # vzctl create 102 # vzctl create 103
Set container weights:
# vzctl set 101 --cpuunits 1000 --save # vzctl set 102 --cpuunits 2000 --save # vzctl set 103 --cpuunits 3000 --save
We set next CPU sharing CT101 : CT102 : CT103 = 1 : 2 : 3
Start containers:
# vzctl start 101 # vzctl start 102 # vzctl start 103
Run busy loops in all containers:
# vzctl enter 101 [ve101]# while [ true ]; do true; done # vzctl enter 102 [ve102]# while [ true ]; do true; done # vzctl enter 103 [ve103]# while [ true ]; do true; done
Check in top that sharing works:
# top COMMAND %CPU bash 48.0 bash 34.0 bash 17.5
So, we see that CPU time is given to container in proportion ~ 1 : 2 : 3.
Now start some more busy loops. CPU distribution should remain the same.
Disk quota
# vzctl set CTID --diskspace 1048576:1153434 --save # vzctl start CTID # vzctl enter CTID [ve]# dd if=/dev/zero of=/tmp/tmp.file bs=1048576 count=1000 dd: writing `/tmp/tmp.file': Disk quota exceeded