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KVM manage virtual machines with virsh

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Virsh is the main interface for managing virsh guest domains. The program can be used to create, pause, and shutdown domains.

Some of this commands may be helpful if you have no chance to run virt-manager.

Show guest information:

Show a list of all running guests: virsh list
Show a list of all available guests: virsh list –all
Show a guest’s info: virsh dominfo GUEST_NAME
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Ubuntu: freenx server installation

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Next Generation Remote Display – NX is an exciting new technology for remote display. It provides near local speed application responsiveness over high latency, low bandwidth links.

Was tested on Ubuntu 10.10 Codenamed “Maverick Meerkat”. Works on Debian 6 too;)

Edit your source list or create a new one:

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vim /etc/apt/sources.list.d/freenx.list

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Pacemaker: fix timeout warnings

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Sometimes if you add a new resource or change something in your cluster configuration you get some warnings like this one.

Or if you run a configuration syntax check:

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root@node1:~# crm configure verify
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crm(live)configure# verify 
WARNING: mount_srv: default timeout 20s for start is smaller than the advised 60
WARNING: mount_srv: default timeout 20s for stop is smaller than the advised 60
WARNING: drbd_r0: default timeout 20s for start is smaller than the advised 240
WARNING: drbd_r0: default timeout 20s for stop is smaller than the advised 100
WARNING: pingnet: default timeout 20s for start is smaller than the advised 60
WARNING: pingnet: default timeout 20s for monitor_0 is smaller than the advised 60

Solution: define new operations, use the same times 240s and 100s
op start interval=”0″ timeout=”240s”
op stop interval=”0″ timeout=”100s”

Config snippet:

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primitive drbd_r0 ocf:linbit:drbd \
        params drbd_resource="drbd0" \
        op monitor interval="120s" \
        op start interval="0" timeout="240s" \
        op stop interval="0" timeout="100s"

Really dirty fix (set global timeouts):

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crm configure property default-action-timeout="240"

DRBD set sync speed

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The default sync rate is normally defined in your drbd configuration (mostly /etc/drbd.conf)

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syncer {
    rate 100M; 
}

If you are setting up a virtual machine on drbd cluster you need to produce more I/O and your physical machines are under heavy load. You can stop some services or you can reduce the sync rate.

Set temporary sync rate:
You need to issue this command only on one of your nodes!

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root@drbd-node1:~# drbdsetup /dev/drbd0 syncer -r 10M

Enjoy the easy solution;)