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https://issues.apache.org/jira/browse/VCL-1023?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15928284#comment-15928284
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ASF subversion and git services commented on VCL-1023:
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Commit 1787209 from [email protected] in branch 'vcl/trunk'
[ https://svn.apache.org/r1787209 ]
VCL-1023
Reworked Semaphore.pm to use the new vcldsemaphore table instead of a lockfile
on the management node. This allows semaphores to be obeyed for vcld processes
running on different management nodes.
Added VMware.pm::get_datastore_directory_semaphore which retrieves a
datastore's URL/UUID identifier and uses this to obtain a semaphore instead of
the descriptive datastore name. This allows semaphores to be obeyed for a
particular directory on a datastore, even if different hosts to mount the same
datastore with using different names.
Updated VMware.pm::prepare_vmdk to use get_datastore_directory_semaphore.
Deleted no longer used subroutines:
* Module.pm::does_semaphore_exist
* Semaphore.pm::get_process_semaphore_ids
* Semaphore.pm::get_reservation_semaphore_ids
* Semaphore.pm::semaphore_exists
* Semaphore.pm::get_lockfile_paths
* Semaphore.pm::release_lockfile
Updated Module.pm to not call 'use VCL::Module::Semaphore' at the beginning.
This causes subroutine redefined warnings because there's sort of a circular
reference the way Module.pm uses Semaphore.pm and Semaphore.pm inherits from
Module.pm. Added require and import statement inside of
Module.pm::get_semaphore contained within an eval block as a replacement.
Updated new.pm::computer_not_being_used to use
utils.pm::get_vcld_semaphore_info instead of calling
Semaphore.pm::get_process_semaphore_ids.
Other
Added DataStructure.pm::get_connect_method_info_matching_name. It was used for
some experimentation and isn't currently being called, but may be useful in the
future.
Updated Linux.pm::get_network_bridge_info to check for exit statuses > 0
instead of anything != 0. Perl occasionally returns -1 even though the command
was successful.
> Cluster reservations may fail to copy an image if assigned to multiple VM
> hosts sharing a datastore
> ---------------------------------------------------------------------------------------------------
>
> Key: VCL-1023
> URL: https://issues.apache.org/jira/browse/VCL-1023
> Project: VCL
> Issue Type: Bug
> Components: vcld (backend)
> Affects Versions: 2.4.2
> Reporter: Andy Kurth
> Assignee: Andy Kurth
> Fix For: 2.5
>
>
> Conditions:
> * Cluster request
> * Multiple reservations are assigned the same image revision
> * Reservations are assigned to VMs on different VMware ESXi hosts
> * VMware ESXi hosts share a common virtual disk image datastore
> * Image does not yet exist on the datastore and needs to be copied from the
> repository
> Each vcld process checks if the image needs to be copied from the repository
> to the datastore. Since the same image revision was assigned to multiple
> reservations in the cluster request, multiple vcld processes determine the
> image needs to be copied.
> The code does obtain a semaphore before attempting to copy the image.
> However, the semaphore name is based on both the VM host name and image name:
> {noformat}
> 2017-03-14
> 00:25:46|18904|3115170|3222911|new|Module.pm:get_semaphore|1601|created
> 'blade1a1-13-/vmfs/volumes/datastore-1a1_mcnc-fas2554/vmwarelinux-RHEL6hkim224213-v3'
> Semaphore object, memory address: 557fdf0
> 2017-03-14
> 00:25:46|18908|3115170|3222912|new|Module.pm:get_semaphore|1601|created
> 'blade1a1-8-/vmfs/volumes/datastore-1a1_mcnc-fas2554/vmwarelinux-RHEL6hkim224213-v3'
> Semaphore object, memory address: 5023f10
> 2017-03-14
> 00:25:47|18913|3115170|3222914|new|Module.pm:get_semaphore|1601|created
> 'blade1a1-9-/vmfs/volumes/datastore-1a1_mcnc-fas2554/vmwarelinux-RHEL6hkim224213-v3'
> Semaphore object, memory address: 5024518
> 2017-03-14
> 00:25:47|18926|3115170|3222918|new|Module.pm:get_semaphore|1601|created
> 'blade1a1-3-/vmfs/volumes/datastore-1a1_mcnc-fas2554/vmwarelinux-RHEL6hkim224213-v3'
> Semaphore object, memory address: 50256d0
> 2017-03-14
> 00:26:12|18930|3115170|3222919|new|Module.pm:get_semaphore|1601|created
> 'blade1a1-11-/vmfs/volumes/datastore-1a1_mcnc-fas2554/vmwarelinux-RHEL6hkim224213-v3'
> Semaphore object, memory address: 5021988
> 2017-03-14
> 00:31:18|18917|3115170|3222916|new|Module.pm:get_semaphore|1601|created
> 'blade1a1-13-/vmfs/volumes/datastore-1a1_mcnc-fas2554/vmwarelinux-RHEL6hkim224213-v3'
> Semaphore object, memory address: 5578c60
> 2017-03-14
> 00:31:24|18922|3115170|3222917|new|Module.pm:get_semaphore|1601|created
> 'blade1a1-3-/vmfs/volumes/datastore-1a1_mcnc-fas2554/vmwarelinux-RHEL6hkim224213-v3'
> Semaphore object, memory address: 4493e78
> {noformat}
> The first 5 processes each obtained a semaphore within 30 seconds of each
> other. Afterwards, each attempted to copy the .vmdk to the same shared
> directory.
> The last 2 processes obeyed the semaphore and waited several minutes because
> the VM host name was the same as that of another reservation. Once the
> process assigned to the same VM host finished attempting to copy the .vmdk
> and released the semaphore, the last 2 processes checked if the copy was
> still necessary. This is how it is supposed to work for all processes
> copying to the same destination.
> The code should be updated to use a better name for the semaphore. The
> datastore UUID should be used along with the image revision name.
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