[tools] Disable memory autoballooning on openqaw5-xen
svirt job on Xen may fail with:
[2018-07-18T09:54:56.0344 CEST] [debug] Command executed: virsh define /var/lib/libvirt/images/openQA-SUT-3.xml [2018-07-18T09:54:56.0539 CEST] [debug] Command's stdout: Domain openQA-SUT-3 defined from /var/lib/libvirt/images/openQA-SUT-3.xml [2018-07-18T09:54:56.0583 CEST] [debug] Command executed: virsh start openQA-SUT-3 [2018-07-18T09:55:02.0753 CEST] [debug] Command's stderr: error: Failed to start domain openQA-SUT-3 error: operation failed: Failed to balloon domain0 memory
I tried to disable autoballooning on openqaw5-xen.qa.suse.de in the past but perhaps I did not finish it. Here's how to do that: https://www.suse.com/documentation/sles-12/singlehtml/article_vt_best_practices/article_vt_best_practices.html#sec.vt.best.mem.xen.
#1 Updated by okurz over 2 years ago
- Subject changed from [xen][functional] Disable memory autoballooning on openqaw5-xen to [xen][functional][u] Disable memory autoballooning on openqaw5-xen
- Target version set to Milestone 19
Should we really disable autoballooning or rather reduce the amount of machines we execute on that host? Reducing the amount of machines sounds like a more conservative approach. I guess QSF would be fine with a little longer waiting time rather than random failures.
#2 Updated by michalnowak over 2 years ago
The host is capable of running much more than three VMs in parallel (that is our current setup), the problem is that sometimes Xen is not fast enough in "transferring" enough free memory from Dom0 to other (i.e. VM's) domain. Random failure might even happen for the first VM to be starter on the host.
Even our developers suggest to turn it off: "The SLES virt documentation recommends setting dom0_mem and disabling autoballooning. This avoids the pitfalls of autoballooning and is a better approach to managing system memory resources. domain0 can always be manually ballooned later, if needed." (https://bugzilla.suse.com/show_bug.cgi?id=943562#c19)
We should do the same in my opinion:
- disable autoballooning
- restrict DomU to 2-4 GB of RAM
- keep the rest of RAM for VMs