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