Bug 1651747
| Summary: | All virtual machines in an affinity group do not run on same host after migrating one of the VMs with VM Soft Affinity. | ||||||
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| Product: | Red Hat Enterprise Virtualization Manager | Reporter: | Abhishekh Patil <abpatil> | ||||
| Component: | ovirt-engine | Assignee: | Andrej Krejcir <akrejcir> | ||||
| Status: | CLOSED ERRATA | QA Contact: | Polina <pagranat> | ||||
| Severity: | medium | Docs Contact: | |||||
| Priority: | high | ||||||
| Version: | 4.2.7 | CC: | adevolder, akrejcir, amashah, cshao, emarcus, gchakkar, mavital, michal.skrivanek, mkalinin, rbarry, Rhev-m-bugs, rhodain, yquinn | ||||
| Target Milestone: | ovirt-4.3.5 | Flags: | lsvaty:
testing_plan_complete-
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| Target Release: | --- | ||||||
| Hardware: | Unspecified | ||||||
| OS: | Unspecified | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Enhancement | |||||
| Doc Text: |
In this release, the Affinity Enforcement process now includes Soft Virtual Machine Affinity.
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Story Points: | --- | ||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2019-08-12 11:53:27 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: | |||||||
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Description
Abhishekh Patil
2018-11-20 16:45:41 UTC
This still appears to be reproducible (I encountered it today) Yanir, are there any changes to the default scheduling policy needed to make this work as expected? The policies I looked at today already had values for affinity set to priority 10 Looking at the code, the component responsible for migrating VMs that break affinity rules (AffinityRulesEnforcementManager) does not consider soft VM-VM affinity when choosing a VM to migrate. I think this is a bug, AREM should try to correct soft VM-VM affinity too. Currently the soft VM-VM affinity is only used when starting or migrating a VM and during balancing. But the balancing chooses which VM to migrate based on CPU and memory load, not affinity rules. So in case the hosts are not overloaded, the VMs will not be migrated even if they break soft affinity. Can someone help to check whether this bug is similar to this bug: Bug 1678708 This bug is about enabling the automatic migration which fixes broken affinity groups even for soft VM affinity groups. And Bug 1678708 looks to be about VM soft affinity not applying when starting VMs. These bugs are different. Hi Andrej, I'm testing on ovirt-engine-4.3.5.1-0.1.el7.noarch. according to the bz the patch must be there . But I see some unexpected behavior. Sometimes I migrate the VM1 (placed in soft positive VMs affinity rule) and the VM2 is balanced as expected (because of the affinity rule) to the same new host to be together with VM1. But in most cases I see another behavior: I migrate the VM1 and wait for the VM2 to be balanced. Instead, though I see that the VM1 is balanced back to the source host. like this : Jun 23, 2019, 3:40:04 PM Migration started (VM: golden_env_mixed_virtio_0, Source: host_mixed_1, Destination: host_mixed_2, User: admin@internal-authz). Jun 23, 2019, 3:40:27 PM Migration completed (VM: golden_env_mixed_virtio_0, Source: host_mixed_1, Destination: host_mixed_2, Duration: 12 seconds, Total: 22 seconds, Actual downtime: 59ms) Jun 23, 2019, 3:40:57 PM Migration initiated by system (VM: golden_env_mixed_virtio_0, Source: host_mixed_2, Destination: host_mixed_1, Reason: Affinity rules enforcement) Jun 23, 2019, 3:41:12 PM Migration completed (VM: golden_env_mixed_virtio_0, Source: host_mixed_2, Destination: host_mixed_1, Duration: 4 seconds, Total: 14 seconds, Actual downtime: 63ms) I attach engine log with scheduler debug . Please see example starting from the line 2019-06-23 15:40:04,502+03 INFO [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (default task-3) [5a79e5ef-c2aa-409d-b606-c26b6f778088] EVENT_ID: VM_MIGRATION_START(62), Migration started (VM: golden_env_mixed_virtio_0, Source: host_mixed_1, Destination: host_mixed_2, User: admin@internal-authz). Two VMs are running on host_mixed_1 . I migrate VM golden_env_mixed_virtio_0 to the host_mixed_2 . It succeeds and then after 30 sec this VM is balanced back instead of expected the second VM golden_env_mixed_virtio_1 to be migrated to the host host_mixed_2. Could you please look? Created attachment 1583695 [details]
engine with debug
That is the expected behavior. The affinity enforcement just tries to migrate VMs such that the affinity is not broken. It does not matter if VM2 migrates to VM1 or VM1 migrates back to VM2, both cases are ok, since the affinity is fixed. In case the user does not want VM1 to migrate back, its migration mode should be set to "manual migration only". verified on the base of https://bugzilla.redhat.com/show_bug.cgi?id=1651747#c22 and #c24 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-2019:2431 sync2jira sync2jira |