ltm pool¶

ltm pool(1) BIG-IP TMSH Manual ltm pool(1)

NAME
pool - Configures load balancing pools for the Local Traffic Manager.

MODULE
ltm

SYNTAX
Modify the pool component within the ltm module using the syntax shown
in the following sections.

CREATE/MODIFY
create pool [name]
modify pool [name]
options:
all
allow-nat [yes | no]
allow-snat [yes | no]
app-service [[string] | none]
autoscale-group-id [[string] | none]
description [string]
gateway-failsafe-device [string]
ignore-persisted-weight [yes | no]
ip-tos-to-client [pass-through | [integer] ]
ip-tos-to-server [pass-through | [integer] ]
link-qos-to-client [pass-through | [integer] ]
link-qos-to-server [pass-through | [integer] ]
load-balancing-mode [dynamic-ratio-member | dynamic-ratio-node |
fastest-app-response | fastest-node |
least-connections-members |
least-connections-node |
least-sessions |
observed-member | observed-node |
predictive-member | predictive-node |
ratio-least-connections-member |
ratio-least-connections-node |
ratio-member | ratio-node | ratio-session |
round-robin | weighted-least-connections-member |
weighted-least-connections-node]
members [add | delete | modify | replace-all-with] {
[ [node_name:port] ] {
options:
address [ip address]
app-service [[string] | none]
connection-limit [integer]
description [string]
dynamic-ratio [integer]
inherit-profile [enabled | disabled]
logging [enabled | disabled]
monitor [name]
priority-group [integer]
profiles [none | profile_name]
rate-limit [integer]
ratio [integer]
session [user-enabled | user-disabled]
state [ user-up | user-down ]
fqdn {
name [string]
address-family [ipv4 | ipv6]
autopopulate [enabled | disabled]
down-interval [integer]
interval [integer]
}
}
}
members none
metadata
[add | delete | modify] {
[metadata_name ... ] {
value [ "value content" ]
persist [ true | false ]
}
}
min-active-members [integer]
min-up-members [integer]
min-up-members-action [failover | reboot | restart-all]
min-up-members-checking [enabled | disabled]
monitor [name]
profiles [none | profile_name]
queue-on-connection-limit [enabled | disabled]
queue-depth-limit [integer]
queue-time-limit [integer]
reselect-tries [integer]
service-down-action [drop | none | reselect | reset]
slow-ramp-time [integer]

edit pool [ [ [name] | [glob] | [regex] ] ... ]
options:
all-properties
non-default-properties

reset-stats pool
reset-stats pool [ [ [name] | [glob] | [regex] ] ... ]

mv pool [ [[source-name] [destination-name]] | [[name] to-folder [folder-name]] | [[name...name] to-folder [folder-name]] ]
options:
to-folder

DISPLAY
list pool
list pool [ [ [name] | [glob] | [regex] ] ... ]
show running-config pool
show running-config pool [ [ [name] | [glob] | [regex] ] ... ]
options:
all-properties
non-default-properties
one-line
partition

show pool
show pool [name]
options:
all-properties
(default | exa | gig | kil | meg | peta | raw | tera | yotta | zetta)
detail
field-fmt

DELETE
delete pool [name]

Note: You must remove all references to a pool before you can delete
the pool.

DESCRIPTION
You can use this pool component to configure the pool definitions on
the Local Traffic Manager. A load balancing pool is a logical set of
devices, such as Web servers, that you group together to receive and
process traffic.

EXAMPLES
create pool my_pool members add { member 10.2.3.11:http member
10.2.3.12:http }

Creates a Local Traffic Manager pool named my_pool with two members,
10.2.3.11 and 10.2.3.12, using the default values for the pool and pool
members.

delete pool my_pool

Deletes the pool named my_pool.

show pool

Displays statistics and status for all Local Traffic Manager pools in
the system configuration.

show pool all-properties

Displays statistics and status for all Local Traffic Manager pools in
the system configuration.

Note that if the system includes Packet Velocity(r) ASIC (PVA) and PVA
Assist capabilities, this command displays status and statistics for
that feature.

list pool my_pool

Displays properties of the pool named my_pool.

mv /ltm pool /Common/my_pool to-folder /Common/some_folder

Moves an LTM pool named my_pool and all of its Pool Members to the
folder named some_folder, where some_folder has already been created
under /Common.

Please refer to the mv manual page for additional examples on how to
use the mv command.

OPTIONS
all Specifies that you want to modify all of the existing components
of the specified type.

allow-nat
Specifies whether the pool can load balance network address
translation (NAT) connections. The default value is yes.

allow-snat
Specifies whether the pool can load balance secure network address
translation (SNAT) connections. The default value is yes.

app-service
Specifies the name of the application service to which the pool
belongs. The default value is none. Note: If the strict-updates
option is enabled on the application service that owns the object,
you cannot modify or delete the pool. Only the application service
can modify or delete the pool.

autoscale-group-id
Specifies the autoscale-group id as reported by Amazon Web
Services(AWS).

description
User defined description.

gateway-failsafe-device
Specifies that the pool is a gateway failsafe pool in a redundant
configuration. The gateway-failsafe-device identifies the device
that depends on the gateway. If the monitor associated with the
pool reports that the gateway is down, the device goes to the
standby state. The default value for this string is empty, the
feature is not configured.

glob Displays the items that match the glob expression. See help glob
for a description of glob expression syntax.

traffic-acceleration-status
Displays the current Traffic-Acceleration status. Indicates
whether the pool is in-use by or dedicated to a virtual server
that uses a traffic-acceleration profile.

ignore-persisted-weight
Discounts the weight of connections made to pool members selected
through persistence, rather than as a result of the algorithm
configured on the pool. If the connection's weight is ignored,
then it is not treated as a 'pick' for that pool member, and does
not influence subsequent pool member load balancing decisions.

This option only impacts pools configured with one of the
following load balancing modes: observed-member, observed-node,
predictive-member, predictive-node, ratio-least-connections-
member, ratio-least-connections-node, ratio-member, or ratio-node.

The default value is no, which results in persisted pool member
connections being accounted for during load balancing
calculations.

ip-tos-to-client
Specifies the Type of Service (ToS) level to use when sending
packets to a client. The default value is 65535 (pass-through).

ip-tos-to-server
Specifies the ToS level to use when sending packets to a server.
The default value is 65535 (pass-through).

link-qos-to-client
Specifies the Link Quality of Service (QoS) level to use when
sending packets to a client. The default value is 65535 (pass-
through).

link-qos-to-server
Specifies the Link QoS level to use when sending packets to a
server. The default value is 65535 (pass-through).

load-balancing-mode
Specifies the modes that the system uses to load balance name
resolution requests among the members of this pool. The default
value is round-robin.

The options are:

dynamic-ratio-member
Specifies that the system distributes connections based on
various aspects of real-time server performance analysis,
such as the number of current connections per node or the
fastest node response time.

This mode is similar to the dynamic-ratio-node mode, except
that weights are based on continuous monitoring of the
servers and are therefore continually changing.

dynamic-ratio-node
Specifies that the system distributes connections based on
various aspects of real-time server performance analysis,
such as the number of current connections per node or the
fastest node response time.

This mode is similar to the dynamic-ratio-member mode, except
that weights are based on continuous monitoring of the
servers and are therefore continually changing.

fastest-app-response
Specifies that the system passes a new connection based on
the fastest response of all currently active nodes in a pool.
This mode might be particularly useful in environments where
nodes are distributed across different logical networks.

fastest-node
Specifies that the system passes a new connection based on
the fastest response of all pools of which a server is a
member. This mode might be particularly useful in
environments where nodes are distributed across different
logical networks.

least-connections-member
Specifies that the system passes a new connection to the node
that has the least number of current connections in the pool.
This mode works best in environments where the servers or
other equipment you are load balancing have similar
capabilities.

This dynamic load balancing mode distributes connections
based on various aspects of real-time server performance
analysis, such as the current number of connections per node
or the fastest node response time.

least-connections-node
Specifies that the system passes a new connection to the node
that has the least number of current connections out of all
pools of which a node is a member. This mode works best in
environments where the servers or other equipment you are
load balancing have similar capabilities.

This dynamic load balancing mode distributes connections
based on various aspects of real-time server performance
analysis, such as the number of current connections per node,
or the fastest node response time.

least-sessions
Specifies that the system passes a new connection to the node
that has the least number of current sessions. This mode
works best in environments where the servers or other
equipment you are load balancing have similar capabilities.

This dynamic load balancing mode distributes connections
based on various aspects of real-time server performance
analysis, such as the number of current sessions.

observed-member
Specifies that the system ranks nodes based on the number of
connections. Nodes that have a better balance of fewest
connections receive a greater proportion of the connections.

This mode differs from the least-connections-member mode,
which measures connections only at the moment of load
balancing, while the observed-member mode tracks the number
of Layer 4 connections to each node over time and creates a
ratio for load balancing.

This dynamic load balancing mode works well in any
environment, but may be particularly useful in environments
where node performance varies significantly.

observed-node
Specifies that the system ranks nodes based on the number of
connections. Nodes that have a better balance of fewest
connections receive a greater proportion of the connections.

This mode differs from least-connections-node mode, which
measures connections only at the moment of load balancing,
while the observed-node mode tracks the number of Layer 4
connections to each node over time and creates a ratio for
load balancing.

This dynamic load balancing method works well in any
environment, but may be particularly useful in environments
where node performance varies significantly.

predictive-member
Uses the ranking method used by the observed-member mode,
except that the system analyzes the trend of the ranking over
time, determining whether a node's performance is improving
or declining. The nodes in the pool with better performance
rankings that are currently improving, rather than declining,
receive a higher proportion of the connections. This dynamic
load balancing mode works well in any environment.

predictive-node
Uses the ranking method used by the observed-node mode,
except that the system analyzes the trend of the ranking over
time, determining whether a node's performance is improving
or declining. The nodes in the pool with better performance
rankings that are currently improving, rather than declining,
receive a higher proportion of the connections. This dynamic
load balancing mode works well in any environment.

queue-depth-limit
Specifies the maximum number of connections that may
simultaneously be queued to go to any member of this pool.
The default is zero which indicates there is no limit.

queue-on-connection-limit
Enable or disable queuing connections when pool member or
node connection limits are reached. When queuing is not
enabled, new connections are reset when connection limits are
met. The default value is disabled.

queue-time-limit
Specifies the maximum time, in milliseconds, a connection
will remain enqueued. The default is zero which indicates
there is no limit.

ratio-least-connections-member
Specifies that the system weights connections to each pool
member based on the value of the ratio weight defined for
each pool member. If a ratio weight is unspecified, it will
be treated as a default value of '1'.

ratio-least-connections-node
Specifies that the system weights connections to each pool
member based on the value of the ratio weight defined for the
pool member's node. If a ratio weight is unspecified, it will
be treated as a default value of '1'.

ratio-member
Specifies that the number of connections that each machine
receives over time is proportionate to a ratio weight you
define for each machine within the pool.

ratio-node
Specifies that the number of connections that each machine
receives over time is proportionate to a ratio weight you
define for each machine across all pools of which the server
is a member.

ratio-session
Specifies that the number of sessions that each machine
receives over time is proportionate to a ratio weight that
you define for each machine within the pool.

round-robin
Specifies that the system passes each new connection request
to the next server in line, eventually distributing
connections evenly across the array of machines being load
balanced. This mode works well in most configurations,
especially if the equipment that you are load balancing is
roughly equal in processing speed and memory.

weighted-least-connections-member
Specifies that the system passes a new connection to the pool
member that is handling the lowest percentage of the
specified maximum number of concurrent connections allowed.
This mode works best in environments where the servers or
other equipment you are load balancing have different but
quantified capability limits.

This mode requires that you specify a value for the
connection-limit option for all members of the pool, but does
not require all servers or other equipment you are load
balancing to have similar capabilities.

weighted-least-connections-node
Specifies that the system passes a new connection to the node
that is handling the lowest percentage of the specified
connection limit. This mode works best in environments where
the servers or other equipment you are load balancing have
different but quantified capability limits.

This mode requires that you specify a value for the
connection-limit option for all nodes, but does not require
all servers or other equipment you are load balancing to have
similar capabilities.

members
Adds, deletes, or replaces a set of pool members, by specifying a
node name and service port in the format [node name/port]. If a
node by the specified name does not exist, it will be created. You
can configure the following options for a pool member:

address
Specifies the IP address of a pool member if a node by the
name specified does not already exist.

app-service
Specifies the name of the application service to which the
pool member belongs. The default value is none. Note: If the
strict-updates option is enabled on the application service
that owns the object, you cannot modify or delete the pool
member. Only the application service can modify or delete the
pool member.

connection-limit
Specifies the maximum number of concurrent connections
allowed for a pool member. The default value is 0 (zero).

description
User defined description.

dynamic-ratio
Specifies a range of numbers that you want the system to use
in conjunction with the ratio load balancing method. The
default value is 1.

fqdn Specifies the attributes for defining a fully qualified
domain name for the node.

name Specifies the fully-qualified domain name of the node.

address-family
Specifies whether the fqdn should consider IPv4, IPv6,
or IP-agnostic address family.

autopopulate
Specifies whether a node defined by a fully-qualified
domain name should automatically scale to the set of IP
addresses returned by the DNS query. If disabled, only
one ephemeral node is generated from the first IP
address returned by DNS. The default is disabled.

interval
Specifies the interval to instantiate DNS queries on a
fully-qualified domain name. The default is the TTL.

down-interval
Specifies the interval for the domain name resolution
operation when a DNS query fails.

inherit-profile
Specifies whether the pool member inherits the encapsulation
profile from the parent pool. The default value is enabled.
If you disable inheritance, no encapsulation takes place,
unless you specify another encapsulation profile for the pool
member using the profiles attribute.

logging
Specifies whether the monitor applied should log its actions.
Logs are stored in /var/log/monitors/ and are regularly
rotated and compressed. The default value is disabled. This
option isn't a part of configuration and will reset to
disabled on load. This option doesn't sync.

monitor
Specifies the health monitors that are configured to monitor
the pool member. The default value is default, the system
monitors the pool member using the monitors specified for the
pool.

You can specify:

o A single monitor, for example, modify pool mypool
members modify { pool_member_1:80 { monitor http } }.

o Multiple monitors, for example, modify pool mypool
members modify { pool_member_1:80 { monitor http and
https } }.

o A minimum number of monitors, for example, modify pool
mypool members modify { pool_member_1:80 { monitor min 1
of { http https } } }.

o No monitor rule or remove a monitor rule, for example,
modify pool mypool members modify { pool_member_1:80 {
monitor none } }.

profiles
Specifies the encapsulation profile to use for the pool
member, when the inherit-profile attribute is disabled. The
default value is none.

priority-group
Specifies the priority group within the pool for this pool
member. Valid values are 0 through 65535. The system sends
traffic to groups in order of priority. The default value is
0.

rate-limit
Specifies the maximum number of connections per second
allowed for a pool member. The default value is 'disabled'.

ratio
Specifies the weight of the pool member for load balancing
purposes. The default value is 1.

session
Establishing a session with a pool member is establishing the
ability of the client to persist to the pool member when
making new connections. When a pool member is session
disabled, clients that have already established sessions with
the pool member may create new connections, but a client that
has not already established a session may not create a new
one (or make a connection which would create a new session).
This feature is used to gently drain connections from a node,
typically as part of a maintenance operation. The default
value is user-enabled.

The value of this property can be set by system or by user.
If the value is set by system, the property will not be
displayed in "Edit" command. But, users can add this field in
if they need to modify this property. The values which user
can set for this property are user-enabled and user-disabled.

state
user-down forces the pool member offline, overriding
monitors. user-up reverts the user-down. When user-up, this
displays the monitor state.

metadata
Associates user-defined data, each of which has name and value
pair and persistence. The default value is persistent, which saves
the data to the config file.

min-active-members
Specifies the minimum number of members that must be up for
traffic to be confined to a priority group when using priority-
based activation. The default value is 0 (zero). An active member
is a member that is up (not marked down) and is handling fewer
connections than its connection limit.

min-up-members
Specifies the minimum number of pool members that must be up;
otherwise, the system takes the action specified in the min-up-
members-action option.

Use this option for gateway pools in a redundant system where a
unit number is applied to the pool. This indicates that the pool
is configured only on the specified unit.

min-up-members-action
Specifies the action to take if min-up-members-checking is
enabled, and the number of active pool members falls below the
number specified in the min-up-members option. The default value
is failover. The options are:

reboot
Specifies that when the min-up-members-checking option is
enabled, and the number of active pool members is less than
the number specified in the min-up-members option, the system
restarts.

restart-all
Specifies that when the min-up-members-checking option is
enabled, and the number of active pool members is less than
the number specified in the min-up-members option, the system
restarts.

failover
Specifies, for a redundant system, that when the min-up-
members-checking option is enabled, and the number of active
pool members is less than the number specified in the min-up-
members option, the system fails over.

min-up-members-checking
Enables or disables the min-up-members feature. If you enable this
feature, you must also specify a value for both the min-up-members
and min-up-members-action options.

monitor
Specifies the health monitors that the system uses to determine
whether it can use this pool for load balancing. The monitor marks
the pool up or down based on whether the monitor is successful.
The default value is none.

You can specify:

o A single monitor, for example, modify pool mypool monitor
http.

o Multiple monitors, for example, modify pool mypool monitor
http and https.

o A minimum number of monitors, for example, modify pool mypool
monitor min 1 of {http and https}.

o No monitor rule or remove a monitor rule, for example, modify
pool mypool monitor none.

name Specifies a unique name for the component. This option is required
for the commands create, delete, and modify.

partition
Displays the administrative partition within which the pool
resides.

profiles
Specifies the profile to use for encapsulation. The default value
is none, which indicates no encapsulation.

regex
Displays the items that match the regular expression. The regular
expression must be preceded by an at sign (@[regular expression])
to indicate that the identifier is a regular expression. See help
regex for a description of regular expression syntax.

reselect-tries
When set to the default value of 0 (zero) the system does not
attempt to load balance to another pool member after a passive
failure. A passive failure is a pool member connection failure.

When set to any other value, the system attempts to load balance
to another pool member after a passive failure, and if that
attempt also results in a passive failure, the system repeats the
process until the specified number of reselection tries is
reached.

reset-stats
Resets the statistics for the specified component to 0 (zero).

service-down-action
Specifies the action to take if the service specified in the pool
is marked down. The options are:

drop Specifies that the system drops connections when a the
service is marked down.

none Specifies that the system takes no action when a the service
is marked down. This is the default value.

reselect
Specifies that the system reselects a node for the next
packet that comes in on a Layer 4 connection, if the service
of the existing connection is marked down.

reset
Specifies that the system resets when a the service is marked
down.

slow-ramp-time
Specifies, in seconds, the ramp time for the pool. This provides
the ability to cause a pool member that has just been enabled, or
marked up, to receive proportionally less traffic than other
members in the pool. The proportion of traffic the member accepts
is determined by how long the member has been up in comparison to
the value of the slow-ramp-time option for the pool.

For example, if the load-balancing-mode of a pool is round-robin
and it has a slow-ramp-time of 60 seconds, when a pool member has
been up for only 30 seconds, the pool member receives
approximately half the amount of new traffic as other pool members
that have been up for more than 60 seconds. After the pool member
has been up for 45 seconds, it receives approximately three
quarters of the new traffic.

The slow-ramp-time option is particularly useful when used with
the least-connections-member load balancing mode. The default
value is 10.

to-folder
This is used with the mv command to specify a folder in which to
move the pool and its members to.

Note: pools can be moved to any folder under /Common, but
dependencies upon it may restrict moving it out of /Common.

SEE ALSO
create, delete, edit, glob, list, modify, mv, ltm virtual, regex,
reset-stats, show, tmsh

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BIG-IP 2016-10-10 ltm pool(1)