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ganeti(7) Ganeti | Version @GANETI_VERSION@
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===========================================
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Name
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----
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ganeti - cluster-based virtualization management
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Synopsis
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--------
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::
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    # gnt-cluster init cluster1.example.com
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    # gnt-node add node2.example.com
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    # gnt-instance add -n node2.example.com \
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    > -o debootstrap --disk 0:size=30g \
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    > -t plain instance1.example.com
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DESCRIPTION
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-----------
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The Ganeti software manages physical nodes and virtual instances of a
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cluster based on a virtualization software. The current version (2.3)
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supports Xen 3.x and KVM (72 or above) as hypervisors, and LXC as an
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experimental hypervisor.
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Quick start
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-----------
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First you must install the software on all the cluster nodes, either
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from sources or (if available) from a package. The next step is to
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create the initial cluster configuration, using **gnt-cluster init**.
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Then you can add other nodes, or start creating instances.
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Cluster architecture
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--------------------
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In Ganeti 2.0, the architecture of the cluster is a little more
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complicated than in 1.2. The cluster is coordinated by a master daemon
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(**ganeti-masterd**(8)), running on the master node. Each node runs
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(as before) a node daemon, and the master has the RAPI daemon running
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too.
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Node roles
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~~~~~~~~~~
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Each node can be in one of the following states:
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master
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    Only one node per cluster can be in this role, and this node is the
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    one holding the authoritative copy of the cluster configuration and
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    the one that can actually execute commands on the cluster and
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    modify the cluster state. See more details under
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    *Cluster configuration*.
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master_candidate
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    The node receives the full cluster configuration (configuration
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    file and jobs) and can become a master via the
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    **gnt-cluster master-failover** command. Nodes that are not in this
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    state cannot transition into the master role due to missing state.
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regular
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    This the normal state of a node.
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drained
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    Nodes in this state are functioning normally but cannot receive
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    new instances, because the intention is to set them to *offline*
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    or remove them from the cluster.
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offline
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    These nodes are still recorded in the Ganeti configuration, but
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    except for the master daemon startup voting procedure, they are not
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    actually contacted by the master. This state was added in order to
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    allow broken machines (that are being repaired) to remain in the
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    cluster but without creating problems.
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Node flags
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~~~~~~~~~~
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Nodes have two flags which govern which roles they can take:
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master_capable
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    The node can become a master candidate, and furthermore the master
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    node. When this flag is disabled, the node cannot become a
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    candidate; this can be useful for special networking cases, or less
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    reliable hardware.
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vm_capable
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    The node can host instances. When enabled (the default state), the
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    node will participate in instance allocation, capacity calculation,
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    etc. When disabled, the node will be skipped in many cluster checks
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    and operations.
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Node Parameters
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~~~~~~~~~~~~~~~
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The ``ndparams`` refer to node parameters. These can be set as defaults
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on cluster and node group levels, but they take effect for nodes only.
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Currently we support the following node parameters:
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oob_program
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    Path to an executable used as the out-of-band helper as described in
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    the `Ganeti Node OOB Management Framework <design-oob.rst>`_ design
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    document.
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spindle_count
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    This should reflect the I/O performance of local attached storage
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    (e.g. for "file", "plain" and "drbd" disk templates). It doesn't
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    have to match the actual spindle count of (any eventual) mechanical
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    hard-drives, its meaning is site-local and just the relative values
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    matter.
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Hypervisor State Parameters
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Using ``--hypervisor-state`` you can set hypervisor specific states as
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pointed out in ``Ganeti Resource Model <design-resource-model.rst>``.
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The format is: ``hypervisor:option=value``.
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Currently we support the following hypervisor state values:
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mem_total
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  Total node memory, as discovered by this hypervisor
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mem_node
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  Memory used by, or reserved for, the node itself; note that some
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  hypervisors can report this in an authoritative way, other not
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mem_hv
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  Memory used either by the hypervisor itself or lost due to instance
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  allocation rounding; usually this cannot be precisely computed, but
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  only roughly estimated
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cpu_total
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  Total node cpu (core) count; usually this can be discovered
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  automatically
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cpu_node
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  Number of cores reserved for the node itself; this can either be
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  discovered or set manually. Only used for estimating how many VCPUs
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  are left for instances
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Disk State Parameters
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~~~~~~~~~~~~~~~~~~~~~
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Using ``--disk-state`` you can set disk specific states as pointed out
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in ``Ganeti Resource Model <design-resource-model.rst>``.
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The format is: ``storage_type/identifier:option=value``. Where we
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currently just support ``lvm`` as storage type. The identifier in this
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case is the LVM volume group. By default this is ``xenvg``.
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Currently we support the following hypervisor state values:
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disk_total
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  Total disk size (usually discovered automatically)
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disk_reserved
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  Reserved disk size; this is a lower limit on the free space, if such a
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  limit is desired
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disk_overhead
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  Disk that is expected to be used by other volumes (set via
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  ``reserved_lvs``); usually should be zero
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Cluster configuration
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~~~~~~~~~~~~~~~~~~~~~
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The master node keeps and is responsible for the cluster
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configuration. On the filesystem, this is stored under the
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``@LOCALSTATEDIR@/ganeti/lib`` directory, and if the master daemon is
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stopped it can be backed up normally.
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The master daemon will replicate the configuration database called
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``config.data`` and the job files to all the nodes in the master
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candidate role. It will also distribute a copy of some configuration
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values via the *ssconf* files, which are stored in the same directory
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and start with a ``ssconf_`` prefix, to all nodes.
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Jobs
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~~~~
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All cluster modification are done via jobs. A job consists of one
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or more opcodes, and the list of opcodes is processed serially. If
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an opcode fails, the entire job is failed and later opcodes are no
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longer processed. A job can be in one of the following states:
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queued
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    The job has been submitted but not yet processed by the master
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    daemon.
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waiting
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    The job is waiting for for locks before the first of its opcodes.
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canceling
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    The job is waiting for locks, but is has been marked for
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    cancellation. It will not transition to *running*, but to
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    *canceled*.
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running
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    The job is currently being executed.
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canceled
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    The job has been canceled before starting execution.
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success
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    The job has finished successfully.
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error
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    The job has failed during runtime, or the master daemon has been
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    stopped during the job execution.
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Common command line features
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----------------------------
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Options
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~~~~~~~
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Many Ganeti commands provide the following options. The
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availability for a certain command can be checked by calling the
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command using the ``--help`` option.
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**gnt-...** *command* [--dry-run] [--priority {low | normal | high}]
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The ``--dry-run`` option can be used to check whether an operation
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would succeed.
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The option ``--priority`` sets the priority for opcodes submitted
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by the command.
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Defaults
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~~~~~~~~
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For certain commands you can use environment variables to provide
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default command line arguments. Just assign the arguments as a string to
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the corresponding environment variable. The format of that variable
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name is **binary**_*command*. **binary** is the name of the ``gnt-*``
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script all upper case and dashes replaced by underscores, and *command*
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is the command invoked on that script.
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Currently supported commands are ``gnt-node list``, ``gnt-group list``
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and ``gnt-instance list``. So you can configure default command line
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flags by setting ``GNT_NODE_LIST``, ``GNT_GROUP_LIST`` and
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``GNT_INSTANCE_LIST``.
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Field formatting
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----------------
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Multiple ganeti commands use the same framework for tabular listing of
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resources (e.g. **gnt-instance list**, **gnt-node list**, **gnt-group
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list**, **gnt-debug locks**, etc.). For these commands, special states
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are denoted via a special symbol (in terse mode) or a string (in
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verbose mode):
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\*, (offline)
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    The node in question is marked offline, and thus it cannot be
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    queried for data. This result is persistent until the node is
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    de-offlined.
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?, (nodata)
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    Ganeti expected to receive an answer from this entity, but the
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    cluster RPC call failed and/or we didn't receive a valid answer;
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    usually more information is available in the node daemon log (if
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    the node is alive) or the master daemon log. This result is
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    transient, and re-running command might return a different result.
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-, (unavail)
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    The respective field doesn't make sense for this entity;
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    e.g. querying a down instance for its current memory 'live' usage,
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    or querying a non-vm_capable node for disk/memory data. This
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    result is persistent, and until the entity state is changed via
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    ganeti commands, the result won't change.
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??, (unknown)
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    This field is not known (note that this is different from entity
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    being unknown). Either you have mis-typed the field name, or you
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    are using a field that the running Ganeti master daemon doesn't
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    know. This result is persistent, re-running the command won't
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    change it.
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Key-value parameters
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~~~~~~~~~~~~~~~~~~~~
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Multiple options take parameters that are of the form
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``key=value,key=value,...`` or ``category:key=value,...``. Examples
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are the hypervisor parameters, backend parameters, etc. For these,
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it's possible to use values that contain commas by escaping with via a
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backslash (which needs two if not single-quoted, due to shell
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behaviour)::
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  # gnt-instance modify -H kernel_path=an\\,example instance1
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  # gnt-instance modify -H kernel_path='an\,example' instance1
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Query filters
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~~~~~~~~~~~~~
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Most commands listing resources (e.g. instances or nodes) support filtering.
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The filter language is similar to Python expressions with some elements from
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Perl. The language is not generic. Each condition must consist of a field name
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and a value (except for boolean checks), a field can not be compared to another
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field. Keywords are case-sensitive.
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Syntax in pseudo-BNF::
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  <quoted-string> ::= /* String quoted with single or double quotes,
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                         backslash for escaping */
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  <integer> ::= /* Number in base-10 positional notation */
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  <re> ::= /* Regular expression */
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  /*
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    Modifier "i": Case-insensitive matching, see
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    http://docs.python.org/library/re#re.IGNORECASE
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    Modifier "s": Make the "." special character match any character,
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    including newline, see http://docs.python.org/library/re#re.DOTALL
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  */
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  <re-modifiers> ::= /* empty */ | i | s
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  <value> ::= <quoted-string> | <integer>
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  <condition> ::=
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    { /* Value comparison */
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      <field> { == | != } <value>
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      /* Collection membership */
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      | <value> [ not ] in <field>
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      /* Regular expressions (recognized delimiters
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         are "/", "#", "^", and "|"; backslash for escaping)
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      */
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      | <field> { =~ | !~ } m/<re>/<re-modifiers>
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      /* Globbing */
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      | <field> { =* | !* } <quoted-string>
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      /* Boolean */
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      | <field>
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    }
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  <filter> ::=
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    { [ not ] <condition> | ( <filter> ) }
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    [ { and | or } <filter> ]
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Operators:
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*==*
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  Equality
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*!=*
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  Inequality
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*=~*
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  Pattern match using regular expression
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*!~*
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  Logically negated from *=~*
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*=\**
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  Globbing, see **glob**(7), though only * and ? are supported
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*!\**
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  Logically negated from *=\**
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*in*, *not in*
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  Collection membership and negation
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As a shortcut globbing patterns can be specified as names, e.g.
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``gnt-instance list '*.site1' '*.site2'``.
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Common daemon functionality
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---------------------------
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All Ganeti daemons re-open the log file(s) when sent a SIGHUP signal.
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**logrotate**(8) can be used to rotate Ganeti's log files.
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.. vim: set textwidth=72 :
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.. Local Variables:
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.. mode: rst
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.. fill-column: 72
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.. End: