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gnt-node(8) Ganeti | Version @GANETI_VERSION@

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Name

----

gnt-node - Node administration

Synopsis

--------

**gnt-node** {command} [arguments...]

DESCRIPTION

-----------

The **gnt-node** is used for managing the (physical) nodes in the

Ganeti system.

COMMANDS

--------

ADD

~~~

**add** [--readd] [-s *secondary\_ip*] [-g *nodegroup*]

[--master-capable=``yes|no``] [--vm-capable=``yes|no``]

{*nodename*}

Adds the given node to the cluster.

This command is used to join a new node to the cluster. You will

have to provide the password for root of the node to be able to add

the node in the cluster. The command needs to be run on the Ganeti

master.

Note that the command is potentially destructive, as it will

forcibly join the specified host the cluster, not paying attention

to its current status (it could be already in a cluster, etc.)

The ``-s`` is used in dual-home clusters and specifies the new node's

IP in the secondary network. See the discussion in **gnt-cluster**(8)

for more information.

In case you're readding a node after hardware failure, you can use

the ``--readd`` parameter. In this case, you don't need to pass the

secondary IP again, it will reused from the cluster. Also, the

drained and offline flags of the node will be cleared before

re-adding it.

The ``-g`` is used to add the new node into a specific node group,

specified by UUID or name. If only one node group exists you can

skip this option, otherwise it's mandatory.

The ``vm_capable`` and ``master_capable`` options are described in

**ganeti**(7), and are used to set the properties of the new node.

Example::

    # gnt-node add node5.example.com

    # gnt-node add -s 192.0.2.5 node5.example.com

    # gnt-node add -g group2 -s 192.0.2.9 node9.group2.example.com

ADD-TAGS

~~~~~~~~

**add-tags** [--from *file*] {*nodename*} {*tag*...}

Add tags to the given node. If any of the tags contains invalid

characters, the entire operation will abort.

If the ``--from`` option is given, the list of tags will be

extended with the contents of that file (each line becomes a tag).

In this case, there is not need to pass tags on the command line

(if you do, both sources will be used). A file name of - will be

interpreted as stdin.

EVACUATE

~~~~~~~~

**evacuate** [-f] [--early-release] [--iallocator *NAME* \|

--new-secondary *destination\_node*] {*node*...}

This command will move all secondary instances away from the given

node(s). It works only for instances having a drbd disk template.

The new location for the instances can be specified in two ways:

- as a single node for all instances, via the ``--new-secondary``

  option

- or via the ``--iallocator`` option, giving a script name as

  parameter, so each instance will be in turn placed on the (per the

  script) optimal node

The ``--early-release`` changes the code so that the old storage on

node being evacuated is removed early (before the resync is

completed) and the internal Ganeti locks are also released for both

the current secondary and the new secondary, thus allowing more

parallelism in the cluster operation. This should be used only when

recovering from a disk failure on the current secondary (thus the

old storage is already broken) or when the storage on the primary

node is known to be fine (thus we won't need the old storage for

potential recovery).

Example::

    # gnt-node evacuate -I dumb node3.example.com

FAILOVER

~~~~~~~~

**failover** [-f] [--ignore-consistency] {*node*}

This command will fail over all instances having the given node as

primary to their secondary nodes. This works only for instances having

a drbd disk template.

Normally the failover will check the consistency of the disks before

failing over the instance. If you are trying to migrate instances off

a dead node, this will fail. Use the ``--ignore-consistency`` option

for this purpose.

Example::

    # gnt-node failover node1.example.com

INFO

~~~~

**info** [*node*...]

Show detailed information about the nodes in the cluster. If you

don't give any arguments, all nodes will be shows, otherwise the

output will be restricted to the given names.

LIST

~~~~

| **list** [--sync]

| [--no-headers] [--separator=*SEPARATOR*]

| [--units=*UNITS*] [-o *[+]FIELD,...*]

| [--roman]

| [node...]

Lists the nodes in the cluster.

The ``--no-headers`` option will skip the initial header line. The

``--separator`` option takes an argument which denotes what will be

used between the output fields. Both these options are to help

scripting.

The units used to display the numeric values in the output varies,

depending on the options given. By default, the values will be

formatted in the most appropriate unit. If the ``--separator``

option is given, then the values are shown in mebibytes to allow

parsing by scripts. In both cases, the ``--units`` option can be

used to enforce a given output unit.

By default, the query of nodes will be done in parallel with any

running jobs. This might give inconsistent results for the free

disk/memory. The ``--sync`` can be used to grab locks for all the

nodes and ensure consistent view of the cluster (but this might

stall the query for a long time).

Passing the ``--roman`` option gnt-node list will try to output

some of its fields in a latin-friendly way. This is not the default

for backwards compatibility.

The ``-o`` option takes a comma-separated list of output fields.

The available fields and their meaning are:

name

    the node name

pinst_cnt

    the number of instances having this node as primary

pinst_list

    the list of instances having this node as primary, comma separated

sinst_cnt

    the number of instances having this node as a secondary node

sinst_list

    the list of instances having this node as a secondary node, comma

    separated

pip

    the primary ip of this node (used for cluster communication)

sip

    the secondary ip of this node (used for data replication in dual-ip

    clusters, see gnt-cluster(8)

dtotal

    total disk space in the volume group used for instance disk

    allocations

dfree

    available disk space in the volume group

mtotal

    total memory on the physical node

mnode

    the memory used by the node itself

mfree

    memory available for instance allocations

bootid

    the node bootid value; this is a linux specific feature that

    assigns a new UUID to the node at each boot and can be use to

    detect node reboots (by tracking changes in this value)

tags

    comma-separated list of the node's tags

serial_no

    the so called 'serial number' of the node; this is a numeric field

    that is incremented each time the node is modified, and it can be

    used to detect modifications

ctime

    the creation time of the node; note that this field contains spaces

    and as such it's harder to parse

    if this attribute is not present (e.g. when upgrading from older

    versions), then "N/A" will be shown instead

mtime

    the last modification time of the node; note that this field

    contains spaces and as such it's harder to parse

    if this attribute is not present (e.g. when upgrading from older

    versions), then "N/A" will be shown instead

uuid

    Show the UUID of the node (generated automatically by Ganeti)

ctotal

    the toal number of logical processors

cnodes

    the number of NUMA domains on the node, if the hypervisor can

    export this information

csockets

    the number of physical CPU sockets, if the hypervisor can export

    this information

master_candidate

    whether the node is a master candidate or not

drained

    whether the node is drained or not; the cluster still communicates

    with drained nodes but excludes them from allocation operations

offline

    whether the node is offline or not; if offline, the cluster does

    not communicate with offline nodes; useful for nodes that are not

    reachable in order to avoid delays

role

    A condensed version of the node flags; this field will output a

    one-character field, with the following possible values:

    - *M* for the master node

    - *C* for a master candidate

    - *R* for a regular node

    - *D* for a drained node

    - *O* for an offline node

master_capable

    whether the node can become a master candidate

vm_capable

    whether the node can host instances

group

    the name of the node's group, if known (the query is done without

    locking, so data consistency is not guaranteed)

group.uuid

    the UUID of the node's group

If the value of the option starts with the character ``+``, the new

fields will be added to the default list. This allows to quickly

see the default list plus a few other fields, instead of retyping

the entire list of fields.

Note that some of this fields are known from the configuration of

the cluster (e.g. name, pinst, sinst, pip, sip and thus the master

does not need to contact the node for this data (making the listing

fast if only fields from this set are selected), whereas the other

fields are "live" fields and we need to make a query to the cluster

nodes.

Depending on the virtualization type and implementation details,

the mtotal, mnode and mfree may have slighly varying meanings. For

example, some solutions share the node memory with the pool of

memory used for instances (KVM), whereas others have separate

memory for the node and for the instances (Xen).

If no node names are given, then all nodes are queried. Otherwise,

only the given nodes will be listed.

LIST-TAGS

~~~~~~~~~

**list-tags** {*nodename*}

List the tags of the given node.

MIGRATE

~~~~~~~

**migrate** [-f] [--non-live] [--migration-mode=live\|non-live]

{*node*}

This command will migrate all instances having the given node as

primary to their secondary nodes. This works only for instances

having a drbd disk template.

As for the **gnt-instance migrate** command, the options

``--no-live`` and ``--migration-mode`` can be given to influence

the migration type.

Example::

    # gnt-node migrate node1.example.com

MODIFY

~~~~~~

| **modify** [-f] [--submit]

| [--master-candidate=``yes|no``] [--drained=``yes|no``] [--offline=``yes|no``]

| [--master-capable=``yes|no``] [--vm-capable=``yes|no``] [--auto-promote]

| [-s *secondary_ip*]

| {*node*}

This command changes the role of the node. Each options takes

either a literal yes or no, and only one option should be given as

yes. The meaning of the roles and flags are described in the

manpage **ganeti**(7).

In case a node is demoted from the master candidate role, the

operation will be refused unless you pass the ``--auto-promote``

option. This option will cause the operation to lock all cluster nodes

(thus it will not be able to run in parallel with most other jobs),

but it allows automated maintenance of the cluster candidate pool. If

locking all cluster node is too expensive, another option is to

promote manually another node to master candidate before demoting the

current one.

Example (setting a node offline, which will demote it from master

candidate role if is in that role)::

    # gnt-node modify --offline=yes node1.example.com

The ``-s`` can be used to change the node's secondary ip. No drbd

instances can be running on the node, while this operation is

taking place.

Example (setting the node back to online and master candidate)::

    # gnt-node modify --offline=no --master-candidate=yes node1.example.com

REMOVE

~~~~~~

**remove** {*nodename*}

Removes a node from the cluster. Instances must be removed or

migrated to another cluster before.

Example::

    # gnt-node remove node5.example.com

REMOVE-TAGS

~~~~~~~~~~~

**remove-tags** [--from *file*] {*nodename*} {*tag*...}

Remove tags from the given node. If any of the tags are not

existing on the node, the entire operation will abort.

If the ``--from`` option is given, the list of tags to be removed will

be extended with the contents of that file (each line becomes a tag).

In this case, there is not need to pass tags on the command line (if

you do, tags from both sources will be removed). A file name of - will

be interpreted as stdin.

VOLUMES

~~~~~~~

| **volumes** [--no-headers] [--human-readable]

| [--separator=*SEPARATOR*] [--output=*FIELDS*]

| [*node*...]

Lists all logical volumes and their physical disks from the node(s)

provided.

The ``--no-headers`` option will skip the initial header line. The

``--separator`` option takes an argument which denotes what will be

used between the output fields. Both these options are to help

scripting.

The units used to display the numeric values in the output varies,

depending on the options given. By default, the values will be

formatted in the most appropriate unit. If the ``--separator``

option is given, then the values are shown in mebibytes to allow

parsing by scripts. In both cases, the ``--units`` option can be

used to enforce a given output unit.

The ``-o`` option takes a comma-separated list of output fields.

The available fields and their meaning are:

node

    the node name on which the volume exists

phys

    the physical drive (on which the LVM physical volume lives)

vg

    the volume group name

name

    the logical volume name

size

    the logical volume size

instance

    The name of the instance to which this volume belongs, or (in case

    it's an orphan volume) the character "-"

Example::

    # gnt-node volumes node5.example.com

    Node              PhysDev   VG    Name                                 Size Instance

    node1.example.com /dev/hdc1 xenvg instance1.example.com-sda_11000.meta 128  instance1.example.com

    node1.example.com /dev/hdc1 xenvg instance1.example.com-sda_11001.data 256  instance1.example.com

LIST-STORAGE

~~~~~~~~~~~~

| **list-storage** [--no-headers] [--human-readable]

| [--separator=*SEPARATOR*] [--storage-type=*STORAGE\_TYPE*]

| [--output=*FIELDS*]

| [*node*...]

Lists the available storage units and their details for the given

node(s).

The ``--no-headers`` option will skip the initial header line. The

``--separator`` option takes an argument which denotes what will be

used between the output fields. Both these options are to help

scripting.

The units used to display the numeric values in the output varies,

depending on the options given. By default, the values will be

formatted in the most appropriate unit. If the ``--separator``

option is given, then the values are shown in mebibytes to allow

parsing by scripts. In both cases, the ``--units`` option can be

used to enforce a given output unit.

The ``--storage-type`` option can be used to choose a storage unit

type. Possible choices are lvm-pv, lvm-vg or file.

The ``-o`` option takes a comma-separated list of output fields.

The available fields and their meaning are:

node

    the node name on which the volume exists

type

    the type of the storage unit (currently just what is passed in via

    ``--storage-type``)

name

    the path/identifier of the storage unit

size

    total size of the unit; for the file type see a note below

used

    used space in the unit; for the file type see a note below

free

    available disk space

allocatable

    whether we the unit is available for allocation (only lvm-pv can

    change this setting, the other types always report true)

Note that for the "file" type, the total disk space might not equal

to the sum of used and free, due to the method Ganeti uses to

compute each of them. The total and free values are computed as the

total and free space values for the filesystem to which the

directory belongs, but the used space is computed from the used

space under that directory *only*, which might not be necessarily

the root of the filesystem, and as such there could be files

outside the file storage directory using disk space and causing a

mismatch in the values.

Example::

    node1# gnt-node list-storage node2

    Node  Type   Name        Size Used   Free Allocatable

    node2 lvm-pv /dev/sda7 673.8G 1.5G 672.3G Y

    node2 lvm-pv /dev/sdb1 698.6G   0M 698.6G Y

MODIFY-STORAGE

~~~~~~~~~~~~~~

**modify-storage** [``--allocatable=yes|no``]

{*node*} {*storage-type*} {*volume-name*}

Modifies storage volumes on a node. Only LVM physical volumes can

be modified at the moment. They have a storage type of "lvm-pv".

Example::

    # gnt-node modify-storage --allocatable no node5.example.com lvm-pv /dev/sdb1

REPAIR-STORAGE

~~~~~~~~~~~~~~

**repair-storage** [--ignore-consistency] {*node*} {*storage-type*}

{*volume-name*}

Repairs a storage volume on a node. Only LVM volume groups can be

repaired at this time. They have the storage type "lvm-vg".

On LVM volume groups, **repair-storage** runs "vgreduce

--removemissing".

**Caution:** Running this command can lead to data loss. Use it with

care.

The ``--ignore-consistency`` option will ignore any inconsistent

disks (on the nodes paired with this one). Use of this option is

most likely to lead to data-loss.

Example::

    # gnt-node repair-storage node5.example.com lvm-vg xenvg

POWERCYCLE

~~~~~~~~~~

**powercycle** [``--yes``] [``--force``] {*node*}

This commands (tries to) forcefully reboot a node. It is a command

that can be used if the node environemnt is broken, such that the

admin can no longer login over ssh, but the Ganeti node daemon is

still working.

Note that this command is not guaranteed to work; it depends on the

hypervisor how effective is the reboot attempt. For Linux, this

command require that the kernel option CONFIG\_MAGIC\_SYSRQ is

enabled.

The ``--yes`` option can be used to skip confirmation, while the

``--force`` option is needed if the target node is the master

node.