fence_virtd.conf(5) fence_virtd.conf(5)

NAME fence_virt.conf - configuration file for fence_virtd

DESCRIPTION The fence_virt.conf file contains configuration information for fence_virtd, a fencing request routing daemon for clusters of virtual machines.

The file is tree-structured. There are parent/child relationships and sibling relationships between the nodes.

foo { bar { baz = "1"; } }

There are three primary sections of fence_virt.conf.

SECTIONS fence_virtd This section contains global information about how fence_virtd is to operate. The most important pieces of information are as follows:

listener the listener plugin for receiving fencing requests from clients

backend the plugin to be used to carry out fencing requests

foreground do not fork into the background.

wait_for_backend wait for the backend management layer to initialize rather than giving up immediately

module_path the module path to search for plugins

listeners This section contains listener-specific configuration information; see the section about listeners below.

backends This section contains listener-specific configuration information; see the section about listeners below.

groups This section contains static maps of which virtual machines may fence which other virtual machines; see the section about groups below.

LISTENERS There are various listeners available for fence_virtd, each one handles decoding and authentication of a given fencing request. The following configuration blocks belong in the listeners section of fence_virt.conf

multicast key_file the shared key file to use (default: /etc/clus- ter/fence_xvm.key).

hash the weakest hashing algorithm allowed for client requests. Clients may send packets with stronger hashes than the one spec- ified, but not weaker ones. (default: sha256, but could be sha1, sha512, or none)

auth the hashing algorithm to use for the simplistic challenge- response authentication (default: sha256, but could be sha1, sha512, or none)

family the IP family to use (default: ipv4, but may be ipv6)

address the multicast address to listen on (default:

port the multicast port to listen on (default: 1229)

interface interface to listen on. By default, fence_virtd listens on the default network interface. However, this causes problems in some environments where the host computer is used as a gateway.

serial The serial listener plugin utilizes libvirt s serial (or VMChannel) mapping to listen for requests. When using the serial listener, it is necessary to add a serial port (preferably pointing to /dev/ttyS1) or a channel (preferrably pointing to to the libvirt domain description. Note that only type unix , mode bind serial ports and channels are supported. Example libvirt XML:

<serial type=unix> <source mode= bind path= /sandbox/guests/fence_socket_molly/> <target port=1/> </serial> <channel type=unix> <source mode= bind path= /sandbox/guests/fence_molly_vmchannel/> <target type=guestfwd address= port=1229/> </channel>

uri the URI to use when connecting to libvirt by the serial plugin.

path Sockets must reside in this directory in order to be considered valid. This can be used to prevent fence_virtd from using the wrong sockets.

mode This selects the type of sockets to register. Valid values are "serial" (default) and "vmchannel".

BACKENDS There are various backends available for fence_virtd, each one handles routing a fencing request to a hypervisor or management tool. The fol- lowing configuration blocks belong in the backends section of fence_virt.conf

libvirt The libvirt plugin is the simplest plugin. It is used in environments where routing fencing requests between multiple hosts is not required, for example by a user running a cluster of virtual machines on a single desktop computer.

uri the URI to use when connecting to libvirt.

libvirt-qpid The libvirt-qpid plugin acts as a QMF Console to the libvirt-qpid dae- mon in order to route fencing requests over AMQP to the appropriate computer. There are currently no configuration options for libvirt- qpid.

host host or IP address of qpid broker. Defaults to

port IP port of qpid broker. Defaults to 5672.

username Username for GSSAPI, if configured.

service Qpid service to connect to.

gssapi If set to 1, have fence_virtd use GSSAPI for authentication when communicating with the Qpid broker. Default is 0 (off).

checkpoint The checkpoint plugin uses CMAN, CPG, and OpenAIS checkpoints to track virtual machines and route fencing requests to the appropriate com- puter.

uri the URI to use when connecting to libvirt by the checkpoint plu- gin.

name_mode The checkpoint plugin, in order to retain compatibility with fence_xvm, stores virtual machines in a certain way in the Ope- nAIS checkpoints. The default was to use name when using fence_xvm and fence_xvmd, and so this is still the default. However, it is strongly recommended to use uuid instead of name in all cluster environments involving more than one phys- ical host in order to avoid the potential for name collisions.

GROUPS Fence_virtd supports static maps which allow grouping of VMs. The groups are arbitrary and are checked at fence time. Any member of a group may fence any other member. Hosts may be assigned to multiple groups if desired.

group This defines a group.

uuid defines UUID as a member of a group.

ip defines an IP which is allowed to send fencing requests for mem- bers of this group (e.g. for multicast). It is highly recom- mended that this be used in conjunction with a key file.

EXAMPLE fence_virtd { listener = "multicast"; backend = "checkpoint"; }

# this is the listeners section

listeners { multicast { key_file = "/etc/cluster/fence_xvm.key"; } }

backends { libvirt { uri = "qemu:///system"; } }

groups { group { ip = ""; uuid = "44179d3f-6c63-474f-a212-20c8b4b25b16"; uuid = "1ce02c4b-dfa1-42cb-b5b1-f0b1091ece60"; } }

SEE ALSO fence_virtd(8), fence_virt(8), fence_xvm(8), fence(8)