Cannot Allocate Memory

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Any of you guys ever seen an issue with Xen 4.4 were xm cannot create a guest because of what looks like an issue allocating memory even though xm info shows like 5x the amount of free memory needed? We are still unfortunately still using xm… it’s on my list, i know..

We’ve had this happen on a couple hosts now. Only way to resolve seams to be rebooting the host. I’m going to update the host to latest Xen
4.4 now hoping this is a old bug.

Here’s from xen logs

[2016-06-22 09:13:50 1958] DEBUG (XendDomainInfo:105)
XendDomainInfo.create([‘vm’, [‘name’, ‘xxx’], [‘memory’, 2048],
[‘on_xend_start’, ‘ignore’], [‘on_xend_stop’, ‘ignore’], [‘vcpus’, 2],
[‘oos’, 1], [‘image’, [‘linux’, [‘kernel’,
‘/kernels/vmlinux-2.6.18.8-4’], [‘videoram’, 4], [‘args’,
‘root=/dev/xvda ro xencons=tty console=tty1 ‘], [‘tsc_mode’, 0],
[‘nomigrate’, 0]]], [‘s3_integrity’, 1], [‘device’, [‘vbd’, [‘uname’,
‘phy:vg/fs_6818’], [‘dev’, ‘xvda’], [‘mode’, ‘w’]]], [‘device’, [‘vbd’,
[‘uname’, ‘phy:vg/fs_6819’], [‘dev’, ‘xvdb’], [‘mode’, ‘w’]]],
[‘device’, [‘vif’, [‘rate’, ’40mb/s’], [‘mac’, ‘FE:FD:48:01:F1:E7’]]]])
[2016-06-22 09:13:50 1958] DEBUG (XendDomainInfo:2504)
XendDomainInfo.constructDomain
[2016-06-22 09:13:50 1958] DEBUG (balloon:187) Balloon: 7602632 KiB
free; need 16384; done.
[2016-06-22 09:13:50 1958] ERROR (XendDomainInfo:2566) (12, ‘Cannot allocate memory’)
Traceback (most recent call last):
File “/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py”, line 2561, in _constructDomain
target = self.info.target())
Error: (12, ‘Cannot allocate memory’)
[2016-06-22 09:13:50 1958] ERROR (XendDomainInfo:490) VM start failed Traceback (most recent call last):
File “/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py”, line 475, in start
XendTask.log_progress(0, 30, self._constructDomain)
File “/usr/lib64/python2.6/site-packages/xen/xend/XendTask.py”, line
209, in log_progress
retval = func(*args, **kwds)
File “/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py”, line 2572, in _constructDomain
raise VmError(failmsg)
VmError: Creating domain failed: name=xxx
[2016-06-22 09:13:50 1958] ERROR (XendDomainInfo:110) Domain construction failed Traceback (most recent call last):
File “/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py”, line 108, in create
vm.start()
File “/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py”, line 475, in start
XendTask.log_progress(0, 30, self._constructDomain)
File “/usr/lib64/python2.6/site-packages/xen/xend/XendTask.py”, line
209, in log_progress
retval = func(*args, **kwds)
File “/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py”, line 2572, in _constructDomain
raise VmError(failmsg)
VmError: Creating domain failed: name=xxx

5 thoughts on - Cannot Allocate Memory

  • xend hasn’t had much love in years, so it’s fairly unlikely that this has been fixed.

    If you haven’t decided to switch to xl, would you mind reposting this question to xen-users? If you do, please also include the output of
    “xl info” after the failure.

    The logs tell us that xend is asking dom0 to free up some memory to use to create the guest. My guess is that there’s a slight mismatch between how much memory xend things needs to be freed and how much memory actually needs freeing.

    Thanks,
    -George

  • Hmm.. so you’re using (dom0) memory ballooning? You might want to disable it. Things worked better without ballooning (at least with xend).

    — Pasi

  • We are planing on moving to xl but have not done so yet.

    Our xend configs are untouched so they should match what they were when the xen-* packages were installed.

    We force dom0 to 1024MB of memory via grub.

    On a couple servers were we’ve seen this issue we’ve had 16+ GB of memory free and the domU was requesting something small like 2GB.

  • We’re using the stock configuration, the dom0 is limited to 1024MB via grub.

    —— Original Message ——
    From: “Pasi Kärkkäinen” To: “Shaun Reitan” ; “Discussion about the virtualization on CentOS”
    Sent: 6/26/2016 9:30:57 AM
    Subject: Re: [CentOS-virt] Cannot allocate Memory

  • Did you try disabling dom0 memory ballooning in xend config ? Does that change anything?

    — Pasi