Created attachment 1216627 [details]
engine log

Description of problem:
Failing to perform memory hotplug for a vm.
When attempting memory hotplug I get an internal error (code 500).
In engine log I get a long trace starting with:

2016-11-02 17:58:40,850 INFO  [org.ovirt.engine.core.bll.UpdateVmCommand] (default task-9) [1da7f3ac] Running command: UpdateVmCommand internal: false. Entities affected :  ID: ff1f7366-c5b2-48d9-9e8e-473a58c832a3 Type: VMAction group EDIT_VM_PROPERTIES with role type USER
2016-11-02 17:58:40,851 WARN  [org.ovirt.engine.core.utils.ObjectIdentityChecker] (default task-9) [1da7f3ac] Field 'balloonEnabled' can not be updated when status is 'Up'
2016-11-02 17:58:40,853 WARN  [org.ovirt.engine.core.utils.ObjectIdentityChecker] (default task-9) [1da7f3ac] Field 'rngDevice' can not be updated when status is 'Up'
2016-11-02 17:58:40,855 WARN  [org.ovirt.engine.core.utils.ObjectIdentityChecker] (default task-9) [1da7f3ac] Field 'soundDeviceEnabled' can not be updated when status is 'Up'
2016-11-02 17:58:40,856 WARN  [org.ovirt.engine.core.utils.ObjectIdentityChecker] (default task-9) [1da7f3ac] Field 'consoleEnabled' can not be updated when status is 'Up'
2016-11-02 17:58:40,858 WARN  [org.ovirt.engine.core.utils.ObjectIdentityChecker] (default task-9) [1da7f3ac] Field 'virtioScsiEnabled' can not be updated when status is 'Up'
2016-11-02 17:58:40,861 WARN  [org.ovirt.engine.core.utils.ObjectIdentityChecker] (default task-9) [1da7f3ac] Field 'graphicsDevices' can not be updated when status is 'Up'
2016-11-02 17:58:40,871 INFO  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogableBase] (default task-9) [1da7f3ac] Failed to get vm 'ff1f7366-c5b2-48d9-9e8e-473a58c832a3', error null
2016-11-02 17:58:40,871 ERROR [org.ovirt.engine.core.bll.CommandsFactory] (default task-9) [1da7f3ac] Error in invocating CTOR of command 'HotSetAmountOfMemory' with parameters 'HotSetAmountOfMemoryParameters:{commandId='2b9b5ef7-b65b-401d-9f38-9d6ab5bb2ff6', user='null', commandType='Unknown', vmId='ff1f7366-c5b2-48d9-9e8e-473a58c832a3'}': null
2016-11-02 17:58:40,931 ERROR [org.ovirt.engine.core.bll.UpdateVmCommand] (default task-9) [1da7f3ac] Command 'org.ovirt.engine.core.bll.UpdateVmCommand' failed: null
2016-11-02 17:58:40,931 ERROR [org.ovirt.engine.core.bll.UpdateVmCommand] (default task-9) [1da7f3ac] Exception: javax.ejb.EJBTransactionRolledbackException




Version-Release number of selected component (if applicable):
tried so far in 2 versions:
ovirt-engine-4.1.0-0.0.master.20161030191240.gitfccaeff.el7.centos.noarch

How reproducible:
always

Steps to Reproduce:
1. Create vm with 1024MB memory with some os installed.
2. Start vm.
3. Edit vm -> change memory to 2048MB

Actual results:
internal error

Expected results:
Vm's memory is expanded to approx. 2048MB

Additional info: