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 ] 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.
Example:
# gnt-node add node5.example.com
# gnt-node add -s 192.168.44.5 node5.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,... ]
[ 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).
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
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 ] 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 --no-live option can be
given to do a non-live migration.
Example:
# gnt-node migrate node1.example.com
MODIFY
modify [ -f ] [ --submit ] [ --master-candidate=yes|no ] [
--drained=yes|no ] [ --offline=yes|no ] [ --auto-promote ] 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 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
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 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.
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.
REPORTING BUGS
Report bugs to <URL:http://code.google.com/p/ganeti/> or contact the
developers using the ganeti mailing list <ganeti@googlegroups.com>.
SEE ALSO
Ganeti overview and specifications: ganeti(7) (general overview),
ganeti-os-interface(7) (guest OS definitions).
Ganeti commands: gnt-cluster(8) (cluster-wide commands), gnt-job(8)
(job-related commands), gnt-node(8) (node-related commands), gnt-
instance(8) (instance commands), gnt-os(8) (guest OS commands), gnt-
backup(8) (instance import/export commands), gnt-debug(8) (debug
commands).
Ganeti daemons: ganeti-watcher(8) (automatic instance restarter),
ganeti-cleaner(8) (job queue cleaner), ganeti-noded(8) (node daemon),
ganeti-masterd(8) (master daemon), ganeti-rapi(8) (remote API daemon).
COPYRIGHT
Copyright (C) 2006, 2007, 2008, 2009 Google Inc. Permission is granted
to copy, distribute and/or modify under the terms of the GNU General
Public License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
On Debian systems, the complete text of the GNU General Public License
can be found in /usr/share/common-licenses/GPL.