nova diagnostics doesn't work with libvirt/qemu,kvm

[Lorin Hochstein]

The "nova diagnostics" command does not currently work with qemu and kvm.

[Lorin Hochstein (lorinh)]

Leander Bessa mentioned working on this bug in the mailing list:

https://lists.launchpad.net/openstack/msg10303.html

[Leander Beernaert (leanderbb)]

So far, whit what i've put together i can get:

- CPU utilization, although it requires a minimum sample time of 1 second
- IO read and write for disks, volumes and network interfaces

I am still unable to retrieve the memory usage. However, i think that might be a libvirt issue, since i can't seem to get the value through the virsh command as well.

How can i submit the code i've made this far?

[Lorin Hochstein (lorinh)]

Leander:

See http://wiki.openstack.org/HowToContribute for how to submit your code.

In a nutshell: you'll need to sign the Contributor Licnse Agreement (CLA), add your name to http://wiki.openstack.org/Contributors and join the https://launchpad.net/~openstack-cla team on Launchpad, then you'll be able to submit your code to Gerrit using the git-review tool.

[Lorin Hochstein (lorinh)]

James Penick from Yahoo said on the mailing list “In the interim, tell those people that code is comin' Real Soon Now.”

[Sean Dague (sdague)]

any progress on this so far?

[Leander Beernaert (leanderbb)]

I'm sorry this is taking so long, but i'm still waiting for some on to sign the CCLA before i can submit my code.

[Leander Beernaert (leanderbb)]

Small update: The CCLA should be signed by the end of the day, and i hope to submit the code by the end of the week :)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/8839

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/8839
Committed: http://github.com/openstack/nova/commit/ad54ed53cf6a475ad0f8042f8b95454a8c0b35a4
Submitter: Jenkins
Branch: master

commit ad54ed53cf6a475ad0f8042f8b95454a8c0b35a4
Author: Leander Bessa Beernaert <email address hidden>
Date: Fri Jun 22 12:08:08 2012 +0100

    Adds diagnostics command for the libvirt driver.

    This code provides an implementation of the get_diagnostics
    API for the libvirt driver. This API is invoked by the
    'nova diagnostic' command.

    There is no existing formal specification for what data items
    to expose from the 'get_diagnostics' API, so the XenAPI driver
    is used as an informal guide. The Xen implementation currently
    produces the following output:

    +----------------+-----------------+
    | Property | Value |
    +----------------+-----------------+
    | cpu0 | 4.3627 |
    | memory | 1171088064.0000 |
    | memory_target | 1171088064.0000 |
    | vbd_xvda_read | 0.0 |
    | vbd_xvda_write | 0.0 |
    | vif_0_rx | 3223.6870 |
    | vif_0_tx | 0.0 |
    | vif_1_rx | 104.4955 |
    | vif_1_tx | 0.0 |
    +----------------+-----------------+

    The new libvirt implementation will return a similar set of stats
    for guest CPUs, memory, disks and network interfaces, resulting
    in the following output:

    +------------------+------------+
    | Property | Value |
    +------------------+------------+
    | cpu0_time | 2870000000 |
    | memory | 524288 |
    | vda_errors | -1 |
    | vda_read | 262144 |
    | vda_read_req | 112 |
    | vda_write | 5606400 |
    | vda_write_req | 376 |
    | vnet0_rx | 63343 |
    | vnet0_rx_drop | 0 |
    | vnet0_rx_errors | 0 |
    | vnet0_rx_packets | 431 |
    | vnet0_tx | 4905 |
    | vnet0_tx_drop | 0 |
    | vnet0_tx_errors | 0 |
    | vnet0_tx_packets | 45 |
    +------------------+------------+

    The implementation has only been tested with the libvirt KVM
    driver.

    In a future a formal specification for the required data
    format should be written and all virt drivers made to comply.

    Finally, the fakelibvirt driver has been updated in order to
    support the methods required by the get_diagnostics method.

    For those interested, below is the formula to extract the
    CPU usage based on the CPU time. I've added it here for reference
    since it's not used at the moment and it took quite a while
    to locate it in the libvirt documentation.

      usage = 100 * (current_cpu_time - last_cpu_time) /
              (measurement_interval * (10 ** 9))

    Fixes bug 986200.
    Change-Id: I92da392f43d0840ed31cfd88f54570ea5830bb4a