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]
autopopulate [enabled | disabled]
}
}
}
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 { 10.2.3.11:http 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
Deprecated since v13.1.0. 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, in seconds, to instantiate DNS queries on a fully-qualified domain
name. The default is 3600. A value of 'ttl' uses the TTL value obtained from the DNS server.

down-interval
Specifies the interval for the domain name resolution operation when a DNS query fails. The
default is 5.

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:

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

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

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

· 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:

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

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

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

· 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

COPYRIGHT
No part of this program may be reproduced or transmitted in any form or by any means, electronic or
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other than the purchaser's personal use, without the express written permission of F5 Networks, Inc.

BIG-IP 2018-10-17 ltm pool(1)