5c8876e763
New section added to explain how to change live_migration_completion_timeout parameter and replacing Configure a Live Migration Completion Timeout in Nova Fixed typo. Signed-off-by: Elisamara Aoki Goncalves <elisamaraaoki.goncalves@windriver.com> Change-Id: If025df41ea6a5e28a258a966f74249b116c26633
109 lines
3.6 KiB
ReStructuredText
109 lines
3.6 KiB
ReStructuredText
.. _configure-a-live-migration-parameters-in-nova-6154238dfc6d:
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===========================================
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Configure Live Migration Parameters in Nova
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===========================================
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.. rubric:: |context|
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You can configure a maximum time for a live migration to complete and/or the
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maximum downtime target for live migration switchover.
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----------
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Parameters
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----------
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- ``live_migration_completion_timeout``
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Time to wait, in seconds, for live migration to successfully complete
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transferring data before aborting the operation.
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Value is per GiB of guest RAM + disk to be transferred, with a lower
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boundary of 2 GiB. Set to 0 to disable timeouts.
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- ``live_migration_downtime``
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The target maximum period of time that Nova will require the |VM| to be
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paused in order to complete the |VM| memory copy. If the transfer rate
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slows down after the |VM| has been paused, this value can be exceeded by a
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small amount of time, it will be rounded up to a minimum of 100ms.
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You may increase this value if you want to allow live-migrations to
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complete faster, or avoid ``live-migration`` timeout errors by allowing the
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guest to be paused longer during the ``live-migration`` switch over.
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Two additional ``live_migration_downtime_scope`` parameters can be
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modified:
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- ``live_migration_downtime_steps``
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Sets the total number of adjustment steps until
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``live_migration_downtime`` is reached. This will let nova increase
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``live_migration_downtime`` gradually until either the switchover has
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been completed or the maximum value has been reached. The default is 10
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steps.
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- ``live_migration_downtime_delay``
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Sets the time interval between two adjustment steps in seconds. The
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default is 75.
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.. rubric:: |proc|
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All the parameters can be modified using the Helm overrides for the |prod-os|
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application.
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#. Create a yaml file containing the configuration update.
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For example ``nova_override.yaml``:
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.. code-block:: none
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conf:
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nova:
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libvirt:
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live_migration_completion_timeout: 300
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live_migration_downtime: 600
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live_migration_downtime_steps: 12
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live_migration_downtime_delay: 50
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#. Update the Helm overrides using the new configuration file.
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.. code-block:: none
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~(keystone_admin)]$ system helm-override-update --values ./nova_override.yaml wr-openstack nova openstack --reuse-values
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#. Confirm that the user override lists the correct live migration parameters.
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.. code-block:: none
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~(keystone_admin)]$ system helm-override-show wr-openstack nova openstack
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#. Apply the changes.
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.. code-block:: none
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~(keystone_admin)]$ system application-apply wr-openstack
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.. rubric:: |result|
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If the live migration aborts because ``live_migration_completion_timeout`` has
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been exceeded, then the following message appears on the ``nova_compute`` logs:
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.. code-block:: none
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WARNING nova.virt.libvirt.migration [-] [instance: 07b5842b-6324-4de0-973e-6d0ff18ef574] Live migration not completed after 300 seconds
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The default behavior is to abort the operation. You can change this action by
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configuring ``live_migration_timeout_action`` in your yaml file.
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For example:
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.. code-block:: none
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live_migration_timeout_action: force_complete
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If it is set to ``force_complete``, the compute service will either pause the
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|VM| or trigger post-copy if post copy is enabled and available
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(``live_migration_permit_post_copy`` is set to True).
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