Bug 1559694
| Summary: | RFE: warn user if VM does not fit in a single numa node of the host | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Virtualization Manager | Reporter: | Germano Veit Michel <gveitmic> |
| Component: | ovirt-engine | Assignee: | Andrej Krejcir <akrejcir> |
| Status: | CLOSED ERRATA | QA Contact: | Polina <pagranat> |
| Severity: | high | Docs Contact: | |
| Priority: | medium | ||
| Version: | 4.1.10 | CC: | lsurette, mavital, michal.skrivanek, mkalinin, mtessun, rbarry, redhat_bugzilla, Rhev-m-bugs, sborella, srevivo, trichard |
| Target Milestone: | ovirt-4.3.0 | Keywords: | FutureFeature |
| Target Release: | 4.3.0 | Flags: | pagranat:
testing_plan_complete+
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| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | verified_upstream | ||
| Fixed In Version: | ovirt-engine-4.3.0_alpha | Doc Type: | Enhancement |
| Doc Text: |
If a VM does not use virtual NUMA nodes, it is better if its whole memory can fit into a single NUMA node on the host. Otherwise, there may be some performance overhead. There are two additions in this RFE:
1. A new warning message is shown in the audit log if a VM is run on a host where its memory cannot fit into a single host NUMA node.
2. A new policy unit is added to the scheduler: 'Fit VM to single host NUMA node'. When starting a VM, this policy prefers hosts where the VM can fit into a single NUMA node. This unit is not active by default, because it can cause undesired edge cases. For example, the policy unit would cause the following behavior when starting multiple VMs:
In the following setup:
- 9 hosts with 16 GB per NUMA node
- 1 host with 4 GB per NUMA node
When multiple VMs with 6 GB of memory are scheduled, the scheduling unit would prevent them from starting on the host with 4 GB per NUMA node, no matter how overloaded the other hosts are. It would use the last host only when all the others do not have enough free memory to run the VM.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2019-05-08 12:37:22 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | Virt | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | |||
| Bug Blocks: | 902971 | ||
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Description
Germano Veit Michel
2018-03-23 03:29:43 UTC
Adding a warning to the audit log when the VM starts should be simple. We can also add a policy to the scheduler so it prefers hosts, where the VM can fit to a single NUMA node. (In reply to Andrej Krejcir from comment #2) > Adding a warning to the audit log when the VM starts should be simple. > > We can also add a policy to the scheduler so it prefers hosts, where the VM > can fit to a single NUMA node. I would go for both. Still there will be cases where a VM will span multiple NUMA nodes, so the warning should be something like "... Consider using vNUMA and NUMA pinning for this VM". Once we have HP Live migration in place the NUMA pinning should no longer prevent the migration. The BZ verification on ovirt-release-master-4.3.0-0.1.master.20180906000056.git3e0522a.el7.noarch ===test1 host numactl -H available: 4 nodes (0-3) node 0 cpus: 0 2 node 0 size: 16349 MB node 0 free: 14036 MB node 1 cpus: 4 6 node 1 size: 8192 MB node 1 free: 6172 MB node 2 cpus: 1 3 node 2 size: 16384 MB node 2 free: 13932 MB node 3 cpus: 5 7 node 3 size: 8175 MB node 3 free: 6251 MB node distances: configure vm without NUMA nodes has memory 18432 MB. it is more than single numa node , but less than the free memory on host. warning in Events appears: "VM golden_env_mixed_virtio_0 does not fit to a single NUMA node on host host_mixed_1. This may negatively impact its performance. Consider using vNUMA and NUMA pinning for this VM." ===test2 set the new policy filter "Fit VM to single host numa node". (Administration -> Configure -> Scheduling Policies. Copy 'none' policy. In the dialog, enable weight module 'Fit VM to single host NUMA node'. two hosts: host1 - numactl -H available: 4 nodes (0-3) node 0 cpus: 0 2 node 0 size: 16349 MB node 0 free: 13684 MB node 1 cpus: 4 6 node 1 size: 8192 MB node 1 free: 5878 MB node 2 cpus: 1 3 node 2 size: 16384 MB node 2 free: 13841 MB node 3 cpus: 5 7 node 3 size: 8175 MB node 3 free: 5722 MB host2 - no numa node Run a VM without NUMA nodes with 18 GB of memory. It runs on the host without numa, even if it could fit on the host with numa. WARN: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{'rhevm-4.3-ga': '?'}', ]
For more info please contact: rhv-devops: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{'rhevm-4.3-ga': '?'}', ]
For more info please contact: rhv-devops
WARN: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{'rhevm-4.3-ga': '?'}', ]
For more info please contact: rhv-devops: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{'rhevm-4.3-ga': '?'}', ]
For more info please contact: rhv-devops
verification - https://bugzilla.redhat.com/show_bug.cgi?id=1559694#c4 Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2019:1085 |