GNT-CLUSTER

NAME

gnt-cluster − ganeti administration, cluster-wide

SYNOPSIS

gnt-cluster command [ arguments... ]

DESCRIPTION

The gnt-cluster is used for cluster-wide administration in the ganeti system.

COMMANDS

ADD-TAGS
add-tags [ --from file ] tag ...

Add tags to the cluster. 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.

COMMAND
command [ -n node ] command

Executes a command on all nodes. If the option -n is not given, the command will be executed on all nodes, otherwise it will be executed only on the node(s) specified. Use the option multiple times for running it on multiple nodes, like:

# gnt-cluster command -n node1.example.com -n node2.example.com date

The command is executed serially on the selected nodes. If the master node is present in the list, the command will be executed last on the master. Regarding the other nodes, the execution order is somewhat alphabetic (it’s smarter so that node2.example.com will be earlier than node10.example.com but after node1.example.com).

So given the node names node1, node2, node3, node10, node11, with node3 being the master, the order will be: node1, node2, node10, node11, node3.

The command is constructed by concatenating all other command line arguments. For example, to list the contents of the /etc directory on all nodes, run:

# gnt-cluster command ls -l /etc

and the command which will be executed will be "ls -l /etc"

COPYFILE
copyfile [ -n node ] file

Copies a file to all or to some nodes. The argument specifies the source file (on the current system), the -n argument specifies the target node, or nodes if the option is given multiple times. If -n is not given at all, the file will be copied to all nodes. Example:

# gnt-cluster -n node1.example.com -n node2.example.com copyfile /tmp/test

This will copy the file /tmp/test from the current node to the two named nodes.

DESTROY
destroy --yes-do-it

Remove all configuration files related to the cluster, so that a gnt-cluster init can be done again afterwards.

Since this is a dangerous command, you are required to pass the argument --yes-do-it.

GETMASTER
getmaster

Displays the current master node.

INFO
info

Shows runtime cluster information: cluster name, architecture (32 or 64 bit), master node, node list and instance list.

INIT
init [ -s secondary_ip ] [ -b bridge ] [ -t hypervisor-type ] [ -g vg-name ] [ --master-netdev vg-name ] [ -m mac-prefix ] clustername

This commands is only run once initially on the first node of the cluster. It will initialize the cluster configuration and setup ssh-keys and more.

Note that the clustername is not any random name. It has to be resolvable to an IP address using DNS, and it is best if you give the fully-qualified domain name. This hostname must resolve to an IP address reserved exclusively for this purpose.

The cluster can run in two modes: single-home or dual-homed. In the first case, all traffic (both public traffic, inter-node traffic and data replication traffic) goes over the same interface. In the dual-homed case, the data replication traffic goes over the second network. The -s option here marks the cluster as dual-homed and its parameter represents this node’s address on the second network. If you initialise the cluster with -s, all nodes added must have a secondary IP as well.

Note that for Ganeti it doesn’t matter if the secondary network is actually a separate physical network, or is done using tunneling, etc. For performance reasons, it’s recommended to use a separate network, of course.

The -b option specifies the default bridge for instances.

The -t allows to set the hypervisor type of the cluster. Available hypervisor types are: xen-3.0, fake and xen-hvm3.1. The default is the xen-3.0 hypervisor. Note that if you init the cluster with hypervisor-type xen-hvm3.1 you also need to provide the cluster VNC password file /etc/ganeti/vnc-cluster-password because HVM instances require it for VNC console authentication.

The -g option will let you specify a volume group different than xenvg for ganeti to use when creating instance disks. This volume group must have the same name on all nodes.

The --master-netdev option is useful for specifying a different interface on which the master will activate its IP address. It’s important that all nodes have this interface because you’ll need it for a master failover.

The -m option will let you specify a three byte prefix under which the virtual MAC addresses of your instances will be generated. The prefix must be specified in the format XX:XX:XX and the default is aa:00:00.

LIST-TAGS
list-tags

List the tags of the cluster.

MASTERFAILOVER
masterfailover

Failover the master role to the current node.

REMOVE-TAGS
remove-tags [ --from file ] tag ...

Remove tags from the cluster. If any of the tags are not existing on the cluster, 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.

RENAME
rename [ -f ] name

Renames the cluster and in the process updates the master IP address to the one the new name resolves to. At least one of either the name or the IP address must be different, otherwise the operation will be aborted.

Note that since this command can be dangerous (especially when run over SSH), the command will require confirmation unless run with the -f option.

SEARCH-TAGS
search-tags pattern

Searches the tags on all objects in the cluster (the cluster itself, the nodes and the instances) for a given pattern. The pattern is interpreted as a regular expression and a search will be done on it (i.e. the given pattern is not anchored to the beggining of the string; if you want that, prefix the pattern with ^).

If no tags are matching the pattern, the exit code of the command will be one. If there is at least one match, the exit code will be zero. Each match is listed on one line, the object and the tag separated by a space. The cluster will be listed as /cluster, a node will be listed as /nodes/name, and an instance as /instances/name. Example:

# gnt-cluster search time
/cluster ctime:2007-09-01
/nodes/node1.example.com mtime:2007-10-04

VERIFY
verify [ --no-nplus1-mem ]

Verify correctness of cluster configuration. This is safe with respect to running instances, and incurs no downtime of the instances.

If the --no-nplus1-mem option is given, ganeti won’t check whether if it loses a node it can restart all the instances on their secondaries (and report an error otherwise).

VERIFY-DISKS
verify-disks

The command checks which instances have degraded DRBD disks and activates the disks of those instances.

This command is run from the ganeti-watcher tool, which also has a different, complementary algorithm for doing this check. Together, these two should ensure that DRBD disks are kept consistent.

VERSION
version

Show the cluster version.

REPORTING BUGS

Report bugs to http://code.google.com/p/ganeti/ or contact the developers using the ganeti mailing list <ganeti AT googlegroups DOT 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-node(8) (node-related commands), gnt-instance(8) (instance commands), gnt-os(8) (guest OS commands). gnt-backup(8) (instance import/export commands).

Ganeti daemons: ganeti-watcher(8) (automatic instance restarter), ganeti-noded(8) (node daemon), ganeti-master(8) (the master startup script), ganeti-rapi(8) (remote API daemon).

COPYRIGHT

Copyright (C) 2006, 2007 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.