LVS.CF(5)LVS.CF(5)NAMElvs.cf - configuration file for lvs
DESCRIPTION
This file contains the configuration information for piranha and is
normally located in /etc/sysconfig/ha/lvs.cf. lvs.cf is read and
updated from the piranha web configuration tool, which uses lvs(8) to
actually work with the file.
GLOBAL OPTIONS
Global settings affect all aspects of the cluster, including virtual
servers and real servers.
service = [lvs|fos]
Indicates which set of defined services are to be used. Virtual
Servers and Failover Services as mutually exclusive; although
they may both be defined in the same config file, thay cannot
both be running simultaneously. This option specifies which
section is to be used.
primary = a.b.c.d
This is the IP (or hostname) of the primary LVS machine.
primary_private = a.b.c.d
Indicates the IP address of an alternative network device for
private heartbeating. It is not necessary to fill out this
field for piranha to work as it simply provides an alternative
method of checking an IP service is running.
backup = a.b.c.d
This is the IP (or hostname) of the backup (or failover) LVS
machine.
backup_private = a.b.c.d
This is akin to primary_private but refers to the alternative IP
device on the backup
backup_active = [0|1]
This dictates if the backup server option is active or inactive.
This option must be set if the backup server is to function in a
failover manner.
heartbeat = [0|1]
Use heartbeat between the two LVS nodes.
keepalive = n
Number of seconds between heartbeats.
deadtime = n
Length of time before a node is declared dead and IP takeover
occurs.
reservation_conflict_action = [nothing|preempt]
This option dictates what action should be taken when a scsi
reservation conflict occurs during failover and the disk is
found to be unexpectedly locked. You should think carefully
about this option as your setup may or may not have a scsi con‐
troller setup to reset the scsi bus on power on or warm reboot.
debug = NONE
Ignore this option. Eventually it will become a means to dictate
how much and what type of information about the state of the
cluster is written to file.
rsh_command =
The command family used to sync file systems and config files.
Allowable options are either rsh (default) or ssh. The appro‐
priate .rhosts (or .ssh/authorized_keys) entries must be on all
nodes so that connections can be made non-interactively.
Sync'ing of specified config files and directories will occur
when lvs receives a SIGUSR1. lvs.cf(5) is automatically synced
between the LVS nodes anytime it is written to.
network = [direct|nat|tunnel]
The lvs virtual server can reroute all of its incoming traffic
via one of three methods; NAT (Network Address Translation),
Direct Routing, or Tunneling (IP Encapsulation).
nat_router = a.b.c.d dev:n
If NAT routing is selected, this specifies the IP address and
device of the routing interface.
nat_nmask = a.b.c.d
Optional. The subnet mask to apply to nat_router.
PER-VIRTUAL SERVER SECTION
A per-virtual server section starts with
virtual server-name {
}
where the string is a unique server identifier. This doesn't have to
match up to a FQDN.
The following items are required for each virtual server entry in the
config file.
address = a.b.c.d
This is the address to be used for the virtual server.
vip_nmask = a.b.c.d
Optional. This is the subnet mask to apply to the address of the
virtual server.
active = [0|1]
This flag is used to indicate whether or not this particular
virtual server is active. If it is marked inactive, then all
real servers being routed to by it will by default become inac‐
tive as well.
The following items are all optional entries (note the default
values for many).
load_monitor = [uptime|rup|ruptime|none]
This specifies the method that the LVS can acquire CPU load
information from the real servers. This load information is
used to adjust the weighting factor for each server entry in the
LVS routing table. Each method requires slightly different con‐
figurations to be present on the real servers and on the LVS
nodes. The default method is uptime. Specifying "none" causes
the service monitor to skip load tests (required for most non-
linux systems).
timeout =
This is the amount of time allowed before a presumed dead real
server is removed from the LVS routing table. Default is 10
seconds.
reentry =
This is the amount of time that a previously dead real server
must be alive before the LVS will re-enter it into the routing
table. The purpose of this delay is to prevent troubled
machines from causing a "ping-pong" effect. The default is 180
seconds.
port = xx
This is the port that the virtual server is instructed to listen
to and redirect network requests from. The default is port 80
(http).
send = xxx
If present, the specified text ("xxx") will be sent to the port
of the virtual server as part of the test for whether the ser‐
vice is operational. The text is limited to 255 characters maxi‐
mum. Characters must be printable/quotable, and may contain "\n,
\r, \\, or \'". Note that if both "send" and "expect" are spec‐
ified, the send will always execute before the read for the
expect is attempted.
send_program = path %h
For more advanced service verification, you can use this direc‐
tive to specify the path to a service-checking script. This
functionality is especially helpful for services that require
dynamically changing data, such as HTTPS or SSL. To use this
functionality, you must write a script that returns a textual
response (that will be matched against 'expect' directive), set
it to be executable, and specify the path to it. To ensure that
each server in the real server pool is checked, use the special
token %h after the path to the script. This token is replaced
with each real server's IP address as the script is called by
the nanny daemon. If 'send_program' is used, then the 'send' is
ignored.
expect = xxx
If present, the specified text ("xxx") will be expected as a
response from the port on the virtual server as part of the test
for whether the service is operational. The text is limited to
255 characters maximum. Characters must be printable/quotable,
and may contain "\n, \r, \\, or \'". Note that if both "send"
and "expect" are specified, the send will always execute before
the read for the expect is attempted. If you wrote your own
service-checking script, enter the response you told it to send
if it was successful.
use_regex = [0|1]
If enabled, the expect string will be interpreted as a regular
expression.
persistent =
The number of seconds that a connection between this virtual
server and a real server will persist. If a request is received
from a client within this number of seconds, it will be assigned
to the same real server that processed a prior request. If this
parameter is missing or set to zero, connections with this vir‐
tual server are not persistent.
pmask =
The network mask to apply to persistence if enabled. Default is
255.255.255.255.
scheduler = [rr|lc|wlc|wrr]
This is the key part of the LVS router. These methods of sched‐
uling how incoming requests are routed are built as loadable
kernel modules: Round Robin (rr), least-connections (lc),
Weighted Least Connections (wlc, the default) and Weighted Round
Robin (wrr).
REAL SERVER SECTIONS
A per-real server section starts with
server servername {
}
where the string is a unique server identifier. This doesn't have to
match up to any real FQDN.
The following items are required for each real server entry in the con‐
fig file.
address = a.b.c.d
This is the actual IP address being used by the real server. In
the cases of NAT type routing, it is generally one of the
reserved, private IPs.
active = [0|1]
This flag is used to indicate whether or not this particular
real server is active.
The following item is optional.
weight =
This option enforces a skew affect by enabling more loading on a
particular server. The weights of all real servers influence
the scheduling algorithm and a higher weight will load a partic‐
ular server down with more redirects. The default value is 1.
An example real server entry might look like:
server 1 {
address = 192.168.10.2
active = 1
weight = 1
}
PER-FAILOVER SERVICE SECTION
A per-failover-service section starts with
failover service-name {
}
where the service-name is a unique identifier.
The following items are required for each failover service entry in the
config file.
address = a.b.c.d dev:x
This is the address and device interface to be used for the vir‐
tual service.
vip_nmask = a.b.c.d
Optional. The netmask to apply to the service address.
active = [0|1]
This flag is used to indicate whether or not this particular
virtual server is active. If it is marked inactive, then all
real servers being routed to by it will by default become inac‐
tive as well.
The following items are all optional entries (note the default
values for many).
timeout =
This is the amount of time allowed before a service is presumed
dead and will cause a failover.
reentry =
This is the amount of time that a previously dead partner system
must be alive before it will be a candidate for possible
failover. The purpose of this delay is to prevent troubled
machines from causing a "ping-pong" effect. The default is 180
seconds.
port = xx
This is the port that the failover service is instructed to
test. The default is port 80 (http).
send = xxx
If present, the specified text ("xxx") will be sent to the port
of the virtual server as part of the test for whether the ser‐
vice is operational. The text is limited to 255 characters maxi‐
mum. Characters must be printable/quotable, and may contain "\n,
\r, \\, or \'". Note that if both "send" and "expect" are spec‐
ified, the send will always execute before the read for the
expect is attempted.
expect = xxx
If present, the specified text ("xxx") will be expected as a
response from the port on the virtual server as part of the test
for whether the service is operational. The text is limited to
255 characters maximum. Characters must be printable/quotable,
and may contain "\n, \r, \\, or \'". Expect can also be a sin‐
gle '*' character to indicate any response characters are
allowed. Note that if both "send" and "expect" are specified,
the send will always execute before the read for the expect is
attempted.
start_cmd = xxx
Mandatory; specifies the startup command/script to execute to
start the failover service. Options can be specified, but must
be separated by a single space.
stop_cmd = xxx
Mandatory; specifies the shutdown command/script to execute to
stop the failover service. Options can be specified, but must be
separated by a single space.
SEE ALSOipvsadm(8), lvs(8), fos(8), pulse(8). sample.cf file
http://www.linuxvirtualserver.org
4 July 2001 LVS.CF(5)
