1 ganeti(7) Ganeti | Version @GANETI_VERSION@
2 ===========================================
7 ganeti - cluster-based virtualization management
14 # gnt-cluster init cluster1.example.com
15 # gnt-node add node2.example.com
16 # gnt-instance add -n node2.example.com \
17 > -o debootstrap --disk 0:size=30g \
18 > -t plain instance1.example.com
24 The Ganeti software manages physical nodes and virtual instances of a
25 cluster based on a virtualization software. The current version (2.3)
26 supports Xen 3.x and KVM (72 or above) as hypervisors, and LXC as an
27 experimental hypervisor.
32 First you must install the software on all the cluster nodes, either
33 from sources or (if available) from a package. The next step is to
34 create the initial cluster configuration, using **gnt-cluster init**.
36 Then you can add other nodes, or start creating instances.
41 In Ganeti 2.0, the architecture of the cluster is a little more
42 complicated than in 1.2. The cluster is coordinated by a master daemon
43 (**ganeti-masterd**(8)), running on the master node. Each node runs
44 (as before) a node daemon, and the master has the RAPI daemon running
50 Each node can be in one of the following states:
53 Only one node per cluster can be in this role, and this node is the
54 one holding the authoritative copy of the cluster configuration and
55 the one that can actually execute commands on the cluster and
56 modify the cluster state. See more details under
57 *Cluster configuration*.
60 The node receives the full cluster configuration (configuration
61 file and jobs) and can become a master via the
62 **gnt-cluster master-failover** command. Nodes that are not in this
63 state cannot transition into the master role due to missing state.
66 This the normal state of a node.
69 Nodes in this state are functioning normally but cannot receive
70 new instances, because the intention is to set them to *offline*
71 or remove them from the cluster.
74 These nodes are still recorded in the Ganeti configuration, but
75 except for the master daemon startup voting procedure, they are not
76 actually contacted by the master. This state was added in order to
77 allow broken machines (that are being repaired) to remain in the
78 cluster but without creating problems.
84 Nodes have two flags which govern which roles they can take:
87 The node can become a master candidate, and furthermore the master
88 node. When this flag is disabled, the node cannot become a
89 candidate; this can be useful for special networking cases, or less
93 The node can host instances. When enabled (the default state), the
94 node will participate in instance allocation, capacity calculation,
95 etc. When disabled, the node will be skipped in many cluster checks
102 These parameters are node specific and can be preseeded on node-group
105 Currently we support the following node parameters:
108 Path to an executable used as the out-of-band helper as described in
109 the `Ganeti Node OOB Management Framework <design-oob.rst>`_ design
113 Cluster configuration
114 ~~~~~~~~~~~~~~~~~~~~~
116 The master node keeps and is responsible for the cluster
117 configuration. On the filesystem, this is stored under the
118 ``@LOCALSTATEDIR@/ganeti/lib`` directory, and if the master daemon is
119 stopped it can be backed up normally.
121 The master daemon will replicate the configuration database called
122 ``config.data`` and the job files to all the nodes in the master
123 candidate role. It will also distribute a copy of some configuration
124 values via the *ssconf* files, which are stored in the same directory
125 and start with a ``ssconf_`` prefix, to all nodes.
130 All cluster modification are done via jobs. A job consists of one
131 or more opcodes, and the list of opcodes is processed serially. If
132 an opcode fails, the entire job is failed and later opcodes are no
133 longer processed. A job can be in one of the following states:
136 The job has been submitted but not yet processed by the master
140 The job is waiting for for locks before the first of its opcodes.
143 The job is waiting for locks, but is has been marked for
144 cancellation. It will not transition to *running*, but to
148 The job is currently being executed.
151 The job has been canceled before starting execution.
154 The job has finished successfully.
157 The job has failed during runtime, or the master daemon has been
158 stopped during the job execution.
164 Many Ganeti commands provide the following options. The
165 availability for a certain command can be checked by calling the
166 command using the ``--help`` option.
168 **gnt-...** *command* [--dry-run] [--priority {low | normal | high}]
170 The ``--dry-run`` option can be used to check whether an operation
173 The option ``--priority`` sets the priority for opcodes submitted
177 Common daemon functionality
178 ---------------------------
180 All Ganeti daemons re-open the log file(s) when sent a SIGHUP signal.
181 **logrotate**(8) can be used to rotate Ganeti's log files.