gnt-node¶

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} secondary_ip]
[{-g|--node-group} nodegroup]
[--master-capable=``yes|no``] [--vm-capable=``yes|no``]
[--node-parameters ndparams]
[--disk-state diskstate]
[--hypervisor-state hvstate]
[--no-node-setup]
{node-name}

Adds the given node to the cluster.

This command is used to join a new node to the cluster. You will have to provide credentials to ssh as root to the node to be added. Forwarding of an ssh agent (the -A option of ssh) works, if an appropriate authorized key is set up on the node to be added. If the other node allows password authentication for root, another way of providing credentials is to provide the root password once asked for it. 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 to the cluster, not paying attention to its current status (it could be already in a cluster, etc.)

The -s (--secondary-ip) 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 re-adding 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 be reused from the cluster. Also, the drained and offline flags of the node will be cleared before re-adding it. Note that even for re-added nodes, a new SSH key is generated and distributed and previous Ganeti keys are removed from the machine.

The -g (--node-group) option 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The --no-node-setup option that used to prevent Ganeti from performing the initial SSH setup on the new node is no longer valid. Instead, Ganeti considers the modify ssh setup configuration parameter (which is set using --no-ssh-init during cluster initialization) to determine whether or not to do the SSH setup on a new node or not. If this parameter is set to False, Ganeti will not touch the SSH keys or the authorized_keys file of the node at all. Using this option, it lies in the administrators responsibility to ensure SSH connectivity between the hosts by other means.

The vm_capable, master_capable, ndparams, diskstate and hvstate options are described in ganeti(7), and are used to set the properties of the new node.

The command performs some operations that change the state of the master and the new node, like copying certificates and starting the node daemon on the new node, or updating /etc/hosts on the master node. If the command fails at a later stage, it doesn’t undo such changes. This should not be a problem, as a successful run of gnt-node add will bring everything back in sync.

If the node was previously part of another cluster and still has daemons running, the node-cleanup tool can be run on the machine to be added to clean remains of the previous cluster from the 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

EVACUATE¶

evacuate [-f] [--early-release] [--submit] [--print-jobid]

[{-I|--iallocator} name | {-n|--new-secondary} destination_node]

[–ignore-soft-errors]

[{-p|--primary-only} | {-s|--secondary-only} ]

{node}

This command will move instances away from the given node. If --primary-only is given, only primary instances are evacuated, with --secondary-only only secondaries. If neither is given, all instances are evacuated. 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 -n (--new-secondary) option
or via the -I (--iallocator) option, giving a script name as parameter (or . to use the default allocator), 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).

Note that this command is equivalent to using per-instance commands for each affected instance individually:

--primary-only is equivalent to performing gnt-instance migrate for every primary instance running on the node that can be migrated and gnt-instance failover for every primary instance that cannot be migrated.
--secondary-only is equivalent to gnt-instance replace-disks in secondary node change mode (--new-secondary) for every DRBD instance that the node is a secondary for.
when neither of the above is done a combination of the two cases is run

Note that the iallocator currently only considers disk information of the default disk template, even if the instance’s disk templates differ from that.

The --ignore-soft-errors option is passed through to the allocator.

See ganeti(7) for a description of --submit and other common options.

Example:

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

Note that, due to an issue with the iallocator interface, evacuation of all instances at once is not yet implemented. Full evacuation can currently be achieved by sequentially evacuating primaries and secondaries.

# gnt-node evacuate -p node3.example.com
# gnt-node evacuate -s 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.

Note that failover will stop any running instances on the given node and restart them again on the new primary. See also FAILOVER in gnt-instance(8).

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 shown, otherwise the output will be restricted to the given names.

LIST¶

list
[--no-headers] [--separator=*SEPARATOR*]
[--units=*UNITS*] [-v] [{-o|--output} [+]FIELD,…]
[--filter]
[node-name…]

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.

Queries of nodes will be done in parallel with any running jobs. This might give inconsistent results for the free disk/memory.

The -v option activates verbose mode, which changes the display of special field states (see ganeti(7)).

The -o (--output) option takes a comma-separated list of output fields. The available fields and their meaning are:

bootid: Random UUID renewed for each system reboot, can be used for detecting reboots by tracking changes
cnodes: Number of NUMA domains on node (if exported by hypervisor)
cnos: Number of logical processors used by the node OS (dom0 for Xen)
csockets: Number of physical CPU sockets (if exported by hypervisor)
ctime: Creation timestamp
ctotal: Number of logical processors
custom_ndparams: Custom node parameters
dfree: Available storage space in storage unit
disk_state: Disk state
drained: Whether node is drained
dtotal: Total storage space in storage unit used for instance disk allocation
group: Node group
group.uuid: UUID of node group
hv_state: Hypervisor state
master: Whether node is master
master_candidate: Whether node is a master candidate
master_capable: Whether node can become a master candidate
mfree: Memory available for instance allocations
mnode: Amount of memory used by node (dom0 for Xen)
mtime: Modification timestamp
mtotal: Total amount of memory of physical machine
name: Node name
ndp/cpu_speed: The “cpu_speed” node parameter
ndp/exclusive_storage: The “exclusive_storage” node parameter
ndp/oob_program: The “oob_program” node parameter
ndp/ovs: The “ovs” node parameter
ndp/ovs_link: The “ovs_link” node parameter
ndp/ovs_name: The “ovs_name” node parameter
ndp/spindle_count: The “spindle_count” node parameter
ndp/ssh_port: The “ssh_port” node parameter
ndparams: Merged node parameters
offline: Whether node is marked offline
pinst_cnt: Number of instances with this node as primary
pinst_list: List of instances with this node as primary
pip: Primary IP address
powered: Whether node is thought to be powered on
role: Node role; “M” for master, “C” for master candidate, “R” for regular, “D” for drained, “O” for offline
serial_no: Node object serial number, incremented on each modification
sinst_cnt: Number of instances with this node as secondary
sinst_list: List of instances with this node as secondary
sip: Secondary IP address
spfree: Available spindles in volume group (exclusive storage only)
sptotal: Total spindles in volume group (exclusive storage only)
tags: Tags
uuid: Node UUID
vm_capable: Whether node can host instances

If the value of the option starts with the character +, the new fields will be added to the default list. This allows one to quickly see the default list plus a few other fields, instead of retyping the entire list of fields.

Note that some of these 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 require a query to the cluster nodes.

Depending on the virtualization type and implementation details, the mtotal, mnode and mfree fields may have slightly 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).

Note that the field ‘dtotal’ and ‘dfree’ refer to the storage type that is defined by the default disk template. The default disk template is the first on in the list of cluster-wide enabled disk templates and can be set with gnt-cluster modify. Currently, only the disk templates ‘plain’, ‘drbd’, ‘file’, and ‘sharedfile’ support storage reporting, for all others ‘0’ is displayed.

If exactly one argument is given and it appears to be a query filter (see ganeti(7)), the query result is filtered accordingly. For ambiguous cases (e.g. a single field name as a filter) the --filter (-F) option forces the argument to be treated as a filter (e.g. gnt-node list -F master_candidate).

If no node names are given, then all nodes are queried. Otherwise, only the given nodes will be listed.

LIST-DRBD¶

list-drbd [--no-headers] [--separator=*SEPARATOR*] node

Lists the mapping of DRBD minors for a given node. This outputs a static list of fields (it doesn’t accept the --output option), as follows:

Node: The (full) name of the node we are querying
Minor: The DRBD minor
Instance: The instance the DRBD minor belongs to
Disk: The disk index that the DRBD minor belongs to
Role: Either primary or secondary, denoting the role of the node for the instance (note: this is not the live status of the DRBD device, but the configuration value)
PeerNode: The node that the minor is connected to on the other end

This command can be used as a reverse lookup (from node and minor) to a given instance, which can be useful when debugging DRBD issues.

Note that this command queries Ganeti via ganeti-confd(8), so it won’t be available if support for confd has not been enabled at build time; furthermore, in Ganeti 2.6 this is only available via the Haskell version of confd (again selected at build time).

LIST-FIELDS¶

list-fields [field…]

Lists available fields for nodes.

MIGRATE¶

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

[--ignore-ipolicy] [--submit] [--print-jobid] {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, --migration-mode and --no-runtime-changes can be given to influence the migration type.

If --ignore-ipolicy is given any instance policy violations occurring during this operation are ignored.

See ganeti(7) for a description of --submit and other common options.

Example:

# gnt-node migrate node1.example.com

MODIFY¶

modify [-f] [--submit] [--print-jobid]
[{-C|--master-candidate} yes|no]
[{-D|--drained} yes|no] [{-O|--offline} yes|no]
[--master-capable=``yes|no``] [--vm-capable=``yes|no``] [--auto-promote]
[{-s|--secondary-ip} secondary_ip]
[--node-parameters ndparams]
[--node-powered=``yes|no``]
[--hypervisor-state hvstate]
[--disk-state diskstate]
{node-name}

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).

The option --node-powered can be used to modify state-of-record if it doesn’t reflect the reality anymore.

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 (--secondary-ip) option 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. Remember that the secondary ip must be reachable from the master secondary ip, when being changed, so be sure that the node has the new IP already configured and active. In order to convert a cluster from single homed to multi-homed or vice versa --force is needed as well, and the target node for the first change must be the master.

See ganeti(7) for a description of --submit and other common options.

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

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

REMOVE¶

remove {node-name}

Removes a node from the cluster. Instances must be removed or migrated to another cluster before.

Example:

# gnt-node remove node5.example.com

VOLUMES¶

volumes [--no-headers] [--human-readable]
[--separator=*SEPARATOR*] [{-o|--output} FIELDS]
[node-name…]

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 (--output) 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*]
[{-o|--output} FIELDS]
[node-name…]

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, file, sharedfile and gluster.

The -o (--output) 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}] [--submit] [--print-jobid]

{node-name} {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] ]--submit]

{node-name} {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] [--submit] [--print-jobid] {node-name}

This command (tries to) forcefully reboot a node. It is a command that can be used if the node environment 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 requires the kernel option CONFIG_MAGIC_SYSRQ to be enabled.

The --yes option can be used to skip confirmation, while the --force option is needed if the target node is the master node.

See ganeti(7) for a description of --submit and other common options.

POWER¶

power [--force] [--ignore-status] [--all] [--power-delay] on|off|cycle|status [node-name…]

This command calls out to out-of-band management to change the power state of given node. With status you get the power status as reported by the out-of-band management script.

Note that this command will only work if the out-of-band functionality is configured and enabled on the cluster. If this is not the case, please use the powercycle command above.

Currently this only has effect for off and cycle. For safety, Ganeti will not allow either of these operations to be run on the master node. However, it will print a command line which can then be run manually on the master. Note that powering off the master is potentially dangerous, and Ganeti does not support doing this.

Providing --force will skip confirmations for the operation.

Providing --ignore-status will ignore the offline=N state of a node and continue with power off.

--power-delay specifies the time in seconds (factions allowed) waited between powering on the next node. This is by default 2 seconds but can increased if needed with this option.

The list of node names is optional. If not provided it will call out for every node in the cluster. Except for the off and cycle command where you’ve to explicit use --all to select all.

HEALTH¶

health [node-name…]

This command calls out to out-of-band management to ask for the health status of all or given nodes. The health contains the node name and then the items element with their status in a item=status manner. Where item is script specific and status can be one of OK, WARNING, CRITICAL or UNKNOWN. Items with status WARNING or CRITICAL are logged and annotated in the command line output.

RESTRICTED-COMMAND¶

restricted-command [-M] [--sync]

{ -g group command | command node-name… }

Executes a restricted command on the specified nodes. Restricted commands are not arbitrary, but must reside in /usr/local/etc/ganeti/restricted-commands on a node, either as a regular file or as a symlink. The directory must be owned by root and not be world- or group-writable. If a command fails verification or otherwise fails to start, the node daemon log must be consulted for more detailed information.

Example for running a command on two nodes:

# gnt-node restricted-command mycommand \
  node1.example.com node2.example.com

The -g option can be used to run a command only on a specific node group, e.g.:

# gnt-node restricted-command -g default mycommand

The -M option can be used to prepend the node name to all command output lines. --sync forces the opcode to acquire the node lock(s) in exclusive mode.

Tags¶

ADD-TAGS¶

add-tags [--from file] {node-name} {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.

REMOVE-TAGS¶

remove-tags [--from file] {node-name} {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.

gnt-node¶

Name¶

Synopsis¶

DESCRIPTION¶

COMMANDS¶

ADD¶

EVACUATE¶

FAILOVER¶

INFO¶

LIST¶

LIST-DRBD¶

LIST-FIELDS¶

MIGRATE¶

MODIFY¶

REMOVE¶

VOLUMES¶

LIST-STORAGE¶

MODIFY-STORAGE¶

REPAIR-STORAGE¶

POWERCYCLE¶

POWER¶

HEALTH¶

RESTRICTED-COMMAND¶

Tags¶

ADD-TAGS¶

REMOVE-TAGS¶

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gnt-node¶

Name¶

Synopsis¶

DESCRIPTION¶

COMMANDS¶

ADD¶

EVACUATE¶

FAILOVER¶

INFO¶

LIST¶

LIST-DRBD¶

LIST-FIELDS¶

MIGRATE¶

MODIFY¶

REMOVE¶

VOLUMES¶

LIST-STORAGE¶

MODIFY-STORAGE¶

REPAIR-STORAGE¶

POWERCYCLE¶

POWER¶

HEALTH¶

RESTRICTED-COMMAND¶

Tags¶

ADD-TAGS¶

LIST-TAGS¶

REMOVE-TAGS¶