79 lines
2.2 KiB
ReStructuredText
79 lines
2.2 KiB
ReStructuredText
.. meta::
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:scope: admin_only
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.. highlight: bash
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:linenothreshold: 5
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===============================================
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Migrate single instance to another compute host
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===============================================
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When you want to move an instance from one compute host to another,
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you can use the ``nova migrate`` command. The scheduler chooses the
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destination compute host based on its settings. This process does
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not assume that the instance has shared storage available on the
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target host.
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#. To list the VMs you want to migrate, run::
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$ nova list
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#. After selecting a VM from the list, run this command where :guilabel:`VM_ID`
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is set to the ID in the list returned in the previous step::
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$ nova show VM_ID
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#. Now, use the ``nova migrate`` command::
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$ nova migrate VM_ID
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#. To migrate of an instance and watch the status, use this example script:
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.. code-block:: bash
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:linenos:
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#!/bin/bash
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# Provide usage
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usage() {
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echo "Usage: $0 VM_ID"
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exit 1
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}
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[[ $# -eq 0 ]] && usage
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# Migrate the VM to an alternate hypervisor
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echo -n "Migrating instance to alternate host"
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$VM_ID=$1
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nova migrate $VM_ID
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VM_OUTPUT=`nova show $VM_ID`
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VM_STATUS=`echo "$VM_OUTPUT" | grep status | awk '{print $4}'`
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while [[ "$VM_STATUS" != "VERIFY_RESIZE" ]]; do
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echo -n "."
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sleep 2
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VM_OUTPUT=`nova show $VM_ID`
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VM_STATUS=`echo "$VM_OUTPUT" | grep status | awk '{print $4}'`
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done
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nova resize-confirm $VM_ID
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echo " instance migrated and resized."
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echo;
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# Show the details for the VM
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echo "Updated instance details:"
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nova show $VM_ID
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# Pause to allow users to examine VM details
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read -p "Pausing, press <enter> to exit."
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.. note::
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If you see this error, it means you are either
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trying the command with the wrong credentials,
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such as a non-admin user, or the ``policy.json``
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file prevents migration for your user:
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``ERROR (Forbidden): Policy doesn't allow compute_extension:admin_actions:migrate
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to be performed. (HTTP 403)``
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The instance is booted from a new host, but preserves its configuration
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including its ID, name, any metadata, IP address, and other properties.
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