nova-compute does not respect reserved memory for dom0 when using libvirt/XEN

[Thomas Kaergel]

When using libvirt/XEN nova-compute does not respect the reserved memory for dom0. Dom0 is skipped in memory calculation in nova/virt/libvirt/driver.py. I suggest introducing of a new config-option named "libvirt_xen_ballooning=bool" which represents the usage of XEN ballooning defaulting to "true" (as this is xen default). If this value is set to false then dom0-memory is included in calculation of used memory.

[Sumanth Nagadavalli (sumanth-nagadavalli)]

Right now, the method, get_memory_mb_used in nova/virt/libvirt/driver.py does the following things for dom0,
m = open('/proc/meminfo').read().split()

idx1 = m.index('MemFree:')
idx2 = m.index('Buffers:')
idx3 = m.index('Cached:')

used += (dom_mem -
                             (int(m[idx1 + 1]) +
                              int(m[idx2 + 1]) +
                              int(m[idx3 + 1])))

Looks like, it is assuming that the ballooning is enabled by default.

Is the expectation to hide it behind a config?

[Geza Gemes (geza-gemes)]

Seems to be a duplicate of bug #1266415, for which fix was commited: https://review.openstack.org/#/c/70835/

[shailendra acharya (acharyashailendra1)]

hello i want to work over this bug, could u help me to reproduce this bug and plz also share useful links

[Eduardo Otubo (otubo)]

Can anyone confirm it is a duplicate of bug #1266415 (with corresponding commit https://review.openstack.org/#/c/70835/)? I want to work on this issue otherwise.

[Markus Zoeller (markus_z) (mzoeller)]

The age and number of assignee changes suggest that this isn't really
a low-hanging-fruit. I'm removing the tag to not confuse new folks who
are searching for that tag.

[Markus Zoeller (markus_z) (mzoeller)]

This is an automated cleanup. This bug report has been closed because it
is older than 18 months and there is no open code change to fix this.
After this time it is unlikely that the circumstances which lead to
the observed issue can be reproduced.

If you can reproduce the bug, please:
* reopen the bug report (set to status "New")
* AND add the detailed steps to reproduce the issue (if applicable)
* AND leave a comment "CONFIRMED FOR: <RELEASE_NAME>"
  Only still supported release names are valid (LIBERTY, MITAKA, OCATA, NEWTON).
  Valid example: CONFIRMED FOR: LIBERTY