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======== |
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Glossary |
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======== |
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.. if you add new entries, keep the alphabetical sorting! |
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.. glossary:: |
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:sorted: |
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ballooning |
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A term describing dynamic changes to an instance's memory while the instance |
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is running that don't require an instance reboot. Depending on the |
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hypervisor and configuration, changes may be automatically initiated by the |
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hypervisor (based on the memory usage of the node and instance), or may need |
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to be initiated manually. |
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BE parameter |
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BE stands for *backend*. BE parameters are hypervisor-independent instance |
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parameters, such as the amount of RAM/virtual CPUs allocated to an instance. |
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DRBD |
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A block device driver that can be used to build RAID1 across the network or |
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across shared storage, while using only locally-attached storage. |
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HV parameter |
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HV stands for *hypervisor*. HV parameters describe the virtualization- |
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specific aspects of the instance. For example, a HV parameter might describe |
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what kernel (if any) to use to boot the instance or what emulation model to |
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use for the emulated hard drives. |
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HVM |
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*Hardware Virtualization Mode*. In this mode, the virtual machine is |
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oblivious to the fact that it is virtualized and all its hardware is |
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emulated. |
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LogicalUnit |
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The code associated with an :term:`OpCode`; for example, the code that |
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implements the startup of an instance. |
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LUXI |
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Local UniX Interface. The IPC method over :manpage:`unix(7)` sockets used |
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between the CLI tools/RAPI daemon and the master daemon. |
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OOB |
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*Out of Band*. This term describes methods of accessing a machine (or parts |
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of a machine) by means other than the usual network connection. Examples |
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include accessing a remote server via a physical serial console or via a |
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virtual console. IPMI is also considered OOB access. |
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OpCode |
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A data structure encapsulating a basic cluster operation; for example: start |
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instance, add instance, etc. |
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PVM |
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(Xen) *Para-virtualization mode*. In this mode, the virtual machine is aware |
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that it is virtualized; therefore, there is no need for hardware emulation |
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or virtualization. |
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SoR |
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*State of Record*. Refers to values/properties that come from an |
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authoritative configuration source. For example, the maximum VCPU over- |
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subscription ratio is a SoR value, but the current over-subscription ratio |
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(based upon how many instances live on the node) is a :term:`SoW` value. |
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SoW |
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*State of the World*. Refers to values that directly describe the world, as |
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opposed to values that come from the configuration (which are considered |
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:term:`SoR`). |
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tmem |
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Xen Transcendent Memory (http://en.wikipedia.org/wiki/Transcendent_memory). |
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tmem is a mechanism used by Xen to provide memory over-subscription. |
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watcher |
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:command:`ganeti-watcher` is a tool that should be run regularly from |
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cron. The tool executes tasks such as restarting failed instances and |
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restarting secondary DRBD devices. For more details, see the man page |
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:manpage:`ganeti-watcher(8)`. |
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