- A term describing runtime, dynamic changes to an instance’s memory,
without having to reboot the instance. Depending on the hypervisor
and configuration, the changes need to be initiated manually, or
they can be automatically initiated by the hypervisor based on the
node and instances memory usage.
- BE parameter
- BE stands for backend. BE parameters are hypervisor-independent
instance parameters such as the amount of RAM/virtual CPUs it has
- A block device driver that can be used to build RAID1 across the
network or even shared storage, while using only locally-attached
- HV parameter
- HV stands for hypervisor. HV parameters are the ones that describe
the virtualization-specific aspects of the instance; for example,
what kernel to use to boot the instance (if any), or what emulation
model to use for the emulated hard drives.
- Hardware virtualization mode, where the virtual machine is oblivious
to the fact that’s being virtualized and all the hardware is
- The code associated with an OpCode, e.g. the code that
implements the startup of an instance.
- Local UniX Interface. The IPC method over unix(7)
sockets used between the CLI tools/RAPI daemon and the master
- Out of Band. This term describes methods of accessing a machine
(or parts of a machine) not via the usual network connection. For
example, accessing a remote server via a physical serial console or
via a virtual one IPMI counts as out of band access.
- A data structure encapsulating a basic cluster operation; for
example, start instance, add instance, etc.
- (Xen) Para-virtualization mode, where the virtual machine knows it’s
being virtualized and as such there is no need for hardware
emulation or virtualization.
- State of Record. Refers to values/properties that come from an
authoritative configuration source. For example, the maximum VCPU
over-subscription ratio is a SoR value, but the current
over-subscription ration (based on how many instances live on the
node) is a SoW value.
- State of the World. Refers to values that describe directly the
world, as opposed to values that come from the
configuration. Contrast with SoR.
- Xen Transcendent Memory
(http://en.wikipedia.org/wiki/Transcendent_memory). It is a
mechanism used by Xen to provide memory over-subscription.
- ganeti-watcher is a tool that should be run regularly
from cron and takes care of restarting failed instances, restarting
secondary DRBD devices, etc. For more details, see the man page