Revision d4fcd298 doc/admin.rst
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The above command has the minimum required options; other options you |
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can give include, among others: |
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- The memory size (``-B memory``) |
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- The maximum/minimum memory size (``-B maxmem``, ``-B minmem``) |
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(``-B memory`` can be used to specify only one size) |
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- The number of virtual CPUs (``-B vcpus``) |
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gnt-instance remove INSTANCE_NAME |
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.. _instance-startup-label: |
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Startup/shutdown |
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~~~~~~~~~~~~~~~~ |
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gnt-instance startup INSTANCE_NAME |
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Ganeti will start an instance with up to its maximum instance memory. If |
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not enough memory is available Ganeti will use all the available memory |
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down to the instance minumum memory. If not even that amount of memory |
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is free Ganeti will refuse to start the instance. |
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Note, that this will not work when an instance is in a permanently |
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stopped state ``offline``. In this case, you will first have to |
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put it back to online mode by running:: |
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does not require dynamically allocated resources (memory and vcpus), |
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after shutting down an instance, execute the following:: |
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gnt-instance modify --ofline INSTANCE_NAME |
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gnt-instance modify --offline INSTANCE_NAME
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.. warning:: Do not use the Xen or KVM commands directly to stop |
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instances. If you run for example ``xm shutdown`` or ``xm destroy`` |
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status), etc. This is harder to parse and is more expensive than the |
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list operation, but returns much more detailed information. |
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Changing an instance's runtime memory |
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+++++++++++++++++++++++++++++++++++++ |
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Ganeti will always make sure an instance has a value between its maximum |
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and its minimum memory available as runtime memory. As of version 2.6 |
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Ganeti will only choose a size different than the maximum size when |
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starting up, failing over, or migrating an instance on a node with less |
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than the maximum memory available. It won't resize other instances in |
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order to free up space for an instance. |
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If you find that you need more memory on a node any instance can be |
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manually resized without downtime, with the command:: |
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gnt-instance modify -m SIZE INSTANCE_NAME |
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The same command can also be used to increase the memory available on an |
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instance, provided that enough free memory is available on its node, and |
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the specified size is not larger than the maximum memory size the |
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instance had when it was first booted (an instance will be unable to see |
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new memory above the maximum that was specified to the hypervisor at its |
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boot time, if it needs to grow further a reboot becomes necessary). |
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Export/Import |
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+++++++++++++ |
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That's it. After the command completes the secondary node is now the |
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primary, and vice-versa. |
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The instance will be started with an amount of memory between its |
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``maxmem`` and its ``minmem`` value, depending on the free memory on its |
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target node, or the operation will fail if that's not possible. See |
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:ref:`instance-startup-label` for details. |
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Live migrating an instance |
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~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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long the migration will take. In any case, for both KVM and Xen |
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hypervisors, the migration will be transparent to the instance. |
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If the destination node has less memory than the instance's current |
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runtime memory, but at least the instance's minimum memory available |
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Ganeti will automatically reduce the instance runtime memory before |
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migrating it, unless the ``--no-runtime-changes`` option is passed, in |
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which case the target node should have at least the instance's current |
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runtime memory free. |
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Moving an instance (offline) |
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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