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Command Reference vA5(1.0) and earlier, Cisco ACE Application Control Engine

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Command Reference vA5(1.0) and earlier, Cisco ACE Application Control Engine

Chapter Title

Real Server Host Configuration Mode Commands

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Updated:: February 17, 2018

Chapter: Real Server Host Configuration Mode Commands

Real Server Host Configuration Mode Commands
Real Server Redirect Configuration Mode Commands

Real Server Host Configuration Mode Commands

Real server host configuration mode commands allow you to create and configure host real servers that are used in server load balancing (SLB). The parameters that you configure determine how the ACE interacts with the servers used for web content and services. For details about SLB, see the Server Load-Balancing Guide, Cisco ACE Application Control Engine.

To create a host real server and access real server host configuration mode, use the rserver host command in configuration mode. The CLI prompt changes to (config-rserver-host). For information about commands available in this mode, see the following commands.

Use the no form of this command to remove an existing real server from the configuration.

rserver [host] name

no rserver name

Syntax Description


name	Unique identifier of the real server. Enter an unquoted text string with no spaces and a maximum of 64 alphanumeric characters.
host	(Optional) Specifies that the real server is a typical server that provides web services and content.

Command Modes

Configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

The commands in this mode require the rserver feature in your user role unless otherwise specified. For details about role-based access control (RBAC) and user roles, see the Virtualization Guide, Cisco ACE Application Control Engine.

All servers in a server farm should be of the same type: host or redirect.

Examples

To create a host server named SERVER1, enter:

host1/Admin(config)# rserver SERVER1

host1/Admin(config-rserver-host)#

To delete the host server named SERVER1, enter:

host1/Admin(config)# no rserver SERVER1

Related Commands

(config-sfarm-host) rserver

(config-rserver-host) conn-limit

To configure the maximum and minimum number of connections that you want to allow for a host real server, use the conn-limit command. Use the no form of this command to reset the maximum number of connections and the minimum connection threshold for a real server to the default of 4000000.

conn-limit max max-conns min min-conns

no conn-limit max

Syntax Description


max maxconns	Specifies the maximum number of connections allowed for this real server. •For the ACE module, enter an integer from 2 to 4000000. •For the ACE appliance, enter an integer from 1 to 4000000. The default is 4000000.
min minconns	Specifies the connection threshold below which the real server will start accepting connections again after the number of connections exceeds the configured maximum number of connections. •For the ACE module, enter an integer from 2 to 4000000. •For the ACE appliance, enter an integer from 1 to 4000000. The default is minconns equal to maxconns.

Command Modes

Real server host configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

Use this command to specify the maximum number of connections and the minimum connection threshold for a real server. The minconns value must be less than or equal to the maxconns value. When the number of connections to a real server reaches the maxconns value, the ACE stops sending connections to that server and assigns it a state of OUTOFSERVICE. The ACE uses the minconns value as a threshold for load balancing to start accepting connections again after the maxconns limit is reached.

Examples

To configure the maximum number of connections and the minimum connection threshold for a real server, enter:

host1/Admin(config-rserver-host)# conn-limit max 65535 min 40000

To reset the maximum number of connections and the minimum connection threshold for a real server to the default of 4000000, enter:

host1/Admin(config-rserver-host)# no conn-limit

Related Commands

(config-rserver-host) rate-limit

(config-rserver-host) description

To configure a description for a real server, use the description command. Use the no form of this command to remove the real server description from the configuration.

description text

no description

Syntax Description


text	User-defined description of the real server and related information. Enter an unquoted text string with a maximum of 240 alphanumeric characters.

Command Modes

Real server host configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

This command has no usage guidelines.

Examples

To configure a description for a real server, enter:

host1/Admin(config-rserver-host)# description database application server

To delete a description for a real server, enter:

host1/Admin(config-rserver-host)# no description

Related Commands

This command has no related commands.

(config-rserver-host) fail-on-all

To configure a real server to remain in the OPERATIONAL state unless all probes associated with it fail (AND logic), use the fail-on-all command in real server host configuration mode. This command is applicable to all probe types. The syntax of this command is:

fail-on-all

no fail-on-all

Syntax Description

This command has no keywords or arguments.

Command Modes

Real server host configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
A2(1.0)	This command was introduced.
A5(1.0)	Added IPv6 support.


ACE Appliance Release	Modification
A3(1.0)	This command was introduced.
A5(1.0)	Added IPv6 support.

Usage Guidelines

This command has no usage guidelines.

Examples

To configure the SERVER1 real server to remain in the OPERATIONAL state unless all associated probes fail, enter the following commands:

host1/Admin(config)# rserver SERVER1

host1/Admin(config-rserver-host)# ip address 2001:DB8:1::1

or

host1/Admin(config-rserver-host)# ip address 192.168.12.15

host1/Admin(config-rserver-host)# probe HTTP_PROBE

host1/Admin(config-rserver-host)# probe ICMP_PROBE

host1/Admin(config-rserver-host)# fail-on-all

To remove the AND probe logic from the real server and return the behavior to the default of OR logic, enter the following command:

host1/Admin(config-rserver-host)# no fail-on-all

Related Commands

This command has no related commands.

(config-rserver-host) inservice

To place a real server in service, use the inservice command in real server host configuration mode. Use the no form of this command to gracefully shut down a real server.

inservice

no inservice

Syntax Description

This command has no keywords or arguments.

Command Modes

Real server host configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

This command requires the real-inservice feature in your user role. For details about role-based access control (RBAC) and user roles, see the Virtualization Guide, Cisco ACE Application Control Engine.

Use the no form of this command to shut down a real server gracefully for maintenance or software upgrades. When you enter this command, the ACE tears down all non-TCP connections. For TCP connections, the ACE allows existing connections to end before taking the server out of service. No new connections are allowed. To place the real server back in service, use the inservice command.

The ACE resets all SSL connections to a particular real server when you enter the no inservice command for that server.

Examples

To place a real server in service, enter:

host1/Admin(config-rserver-host)# inservice

To take a real server out of service, enter:

host1/Admin(config-rserver-host)# no inservice

Related Commands

This command has no related commands.

(config-rserver-host) ip address

To configure an IPv6 or an IPv4 address for a real server, use the ip address command in real server host configuration mode. Use the no form of this command to remove the real server IP address from the configuration.

ip address ip-address

no ip address

Syntax Description


ip-address	IP address for the real server of type host.

Command Modes

Real server host configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

Use this command to provide a unique IP address for a real server. The address that you choose must not be a VIP of an existing virtual server.

Caution

Do not configure under a real server a peer IPv6 address that is calculated from EUI64. In a redundant configuration, if you configure a peer IPv6 address as EUI64 on an interface, the address will not be learned by the active member of an FT group because the address is calculated only on the peer. If you then configure the same calculated IPv6 address on the active under a real server, the CLI accepts it because it does not calculate it. This IPv6 address is not synced to the standby because it conflicts with the interface address. If you subsequently apply a probe to the real server, the state of the real server is PROBE-FAILED on the active and OUTOFSERVICE on the the standby. This same check applies to VIPs, routes, interfaces, and probes.

Examples

IPv6 Example

To configure the IPv6 address of a real server, enter:

host1/Admin(config-rserver-host)# ip address 2001:DB8:1::1

To delete the real server IPv6 address from the configuration, enter:

host1/Admin(config-rserver-host)# no ip address 2001:DB8:1::1

IPv4 Example

To configure the IPv4 address of a real server, enter:

host1/Admin(config-rserver-host)# ip address 192.168.12.6

To delete the real server IPv4 address from the configuration, enter:

host1/Admin(config-rserver-host)# no ip address 192.168.12.6

Related Commands

This command has no related commands.

(config-rserver-host) probe

To configure a probe to monitor the health of a real server, use the probe command. Use the no form of this command to remove the probe from the real server.

probe probe-name

no probe probe-name

Syntax Description


probe-name	Identifier of an existing probe that you want to assign to a real server to monitor its health. Enter an unquoted text string with no spaces and a maximum of 64 alphanumeric characters.

Command Modes

Real server host configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

You can associate multiple probes with each real server.

Examples

To configure a probe for a real server of type host, enter:

host1/Admin(config-rserver-host)# probe SERVER1_PROBE

To remove a probe from a real server of type host, enter:

host1/Admin(config-rserver-host)# no probe SERVER1_PROBE

Related Commands

This command has no related commands.

(config-rserver-host) rate-limit

To configure a limit for the connection rate and the bandwidth rate of a real server, use the rate-limit command. The connection rate is the number of connections per second received by the ACE and applies only to the new connections destined to a real server. The bandwidth rate is the number of bytes per second and applies to the network traffic exchanged between the ACE and the real server in both directions. Use the no form of this command to revert to the ACE default of not limiting the connection rate or bandwidth rate of real servers.

rate-limit {connection number1 | bandwidth number2}

no rate-limit {connection | bandwidth}

Syntax Description


connection number1	Specifies the real server connection-rate limit in connections per second. •For the ACE module, enter an integer from 2 to 350000. •For the ACE appliance, enter an integer from 1 to 350000. There is no default value.
bandwidth number2	Specifies the real server bandwidth-rate limit in bytes per second. •For the ACE module, enter an integer from 4 to 300000000. •For the ACE appliance, enter an integer from 1 to 300000000. There is no default value.

Command Modes

Real server host configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
A2(1.0)	This command was introduced.
A4(1.0)	The lowest real server bandwidth-rate limit was changed from 2 to 4.


ACE Appliance Release	Modification
A3(1.0)	This command was introduced.

Usage Guidelines

For a real server that is associated with more than one server farm, the ACE uses the aggregated connection rate or bandwidth rate to determine whether the real server has exceeded its rate limits. If the connection rate or the bandwidth rate of incoming traffic destined for a particular server exceeds the configured rate of the server, the ACE blocks any further traffic destined to that real server until the connection rate or bandwidth rate drops below the configured limit. Also, the ACE removes the blocked real server from future load-balancing decisions.

You can also limit the connection rate and the bandwidth rate at the virtual server level in a connection parameter map. For details, see the Security Guide, Cisco ACE Application Control Engine.

Examples

To limit the connection rate of a real server to 100,000 connections per second, enter:

host1/Admin(config-rserver-host)# rate-limit connection 100000

To revert to the ACE default of not limiting the real-server connection rate, enter:

host1/Admin(config-rserver-host)# no rate-limit connection

To limit the real-server bandwidth rate to 5,000,000 bytes per second, enter:

host1/Admin(config-rserver-host)# rate-limit bandwidth 5000000

To revert to the ACE default of not limiting real-server bandwidth, enter:

host1/Admin(config-rserver-host)# no rate-limit bandwidth

Related Commands

(config-rserver-host) conn-limit

(config-rserver-host) weight

To configure the capacity of a real server in relation to other servers in a server farm, use the weight command. The weight value that you specify for a server is used in the weighted round-robin and least-connections predictor load-balancing methods. Use the no form of this command to reset the real server weight to the default.

weight number

no weight

Syntax Description


number	Weight value assigned to a real server in a server farm. This value is used in the weighted round-robin and least-connections predictor load-balancing algorithms. Enter an integer from 0 to 100. The default is 8.

Command Modes

Real server host configuration mode.

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

Servers with a higher configured weight value have a higher priority with respect to connections than servers with a lower weight. For example, a server with a weight of 5 would receive five connections for every one connection received by a server with a weight of 1.

To specify different weight values for a real server in a server farm, you can assign multiple IP addresses to the server. You can also use the same IP address of a real server with different port numbers.

Server weights take effect only when there are open connections to the servers. When there are no sustained connections to any of the servers, the leastconns predictor method behaves like the roundrobin method.

Examples

To configure a weight value for a real server, enter:

host1/Admin(config-rserver-host)# weight 50

To reset the weight of a real server to the default of 8, enter:

host1/Admin(config-rserver-host)# no weight

Related Commands

This command has no related commands.

Real Server Redirect Configuration Mode Commands

Real server redirect configuration mode commands allow you to configure parameters for redirection real servers used in server load balancing (SLB). A redirection real server is used only for redirecting network traffic to another server as indicated in the Webhost redirection string. See the (config-rserver-redir) webhost-redirection command. The parameters that you configure determine how the ACE interacts with the servers used for redirection. Redirection servers are useful for content that has physically moved to another location, either temporarily or permanently. For details about SLB and redirection, see the Server Load-Balancing Guide, Cisco ACE Application Control Engine.

To create a redirect real server and access real server configuration mode, use the rserver redirect command in configuration mode. The CLI prompt changes to (config-rserver-redir). For information about commands available in this mode, see the commands that follow this section.

Use the no form of this command to remove an existing real server from the configuration.

rserver redirect name

no rserver redirect name

Syntax Description


name	Unique identifier of the real server. Enter an unquoted text string with no spaces and a maximum of 64 alphanumeric characters.

Command Modes

Configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

All commands in this mode require the Real feature in your user role. For details about role-based access control (RBAC) and user roles, see the Virtualization Guide, Cisco ACE Application Control Engine.

All servers in a server farm should be of the same type: host or redirect.

Examples

To create a redirect server named SERVER1, enter:

host1/Admin(config)# rserver redirect SERVER1

To delete the redirect server named SERVER1, enter:

host1/Admin(config)# no rserver redirect SERVER1

Related Commands

(config-rserver-redir) webhost-redirection

(config-rserver-redir) conn-limit

To configure the maximum and minimum number of connections that you want to allow for a real server, use the conn-limit command. Use the no form of this command to reset the maximum number of connections and the minimum connection threshold for a real server to the default of 4000000.

conn-limit max max-conns min min-conns

no conn-limit max

Syntax Description


max max-conns	Specifies the maximum number of connections allowed for this real server. •For the ACE module, enter an integer from 2 to 4000000. •For the ACE appliance, enter an integer from 1 to 4000000. The default is 4000000.
min min-conns	Specifies the connection threshold below which the real server will start accepting connections again after the number of connections exceeds the configured maximum number of connections. •For the ACE module, enter an integer from 2 to 4000000. •For the ACE appliance, enter an integer from 1 to 4000000. The default is minconns equal to maxconns.

Command Modes

Real server redirect configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

Examples

To configure the maximum number of connections and the minimum connection threshold for a real server, enter:

host1/Admin(config-rserver-redir)# conn-limit maxconns 65535 minconns 40000

To reset the maximum number of connections and the minimum connection threshold for a real server of type redirect to the default of 4000000, enter:

host1/Admin(config-rserver-redir)# no conn-limit

Related Commands

This command has no related commands.

(config-rserver-redir) description

To configure a description for a real server, use the description command. Use the no form of this command to remove the real server description from the configuration.

description text

no description

Syntax Description


text	User-defined description of the real server and related information. Enter an unquoted text string with a maximum of 240 alphanumeric characters.

Command Modes

Real server redirect configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

Use this command to provide a unique description for the real server with a maximum of 240 characters.

Examples

To configure a real server description, enter:

host1/Admin(config-rserver-redir)# description database application server

To delete a real server description, enter:

host1/Admin(config-rserver-redir)# no description

Related Commands

This command has no related commands.

(config-rserver-redir) inservice

To place a real server in service, use the inservice command. Use the no form of this command to remove the real server from service.

inservice

no inservice

Syntax Description

This command has no keywords or arguments.

Command Modes

Real server redirect configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

Examples

To place a real server in service, enter:

host1/Admin(config-rserver-redir)# inservice

To take a real server out of service, enter:

host1/Admin(config-rserver-redir)# no inservice

Related Commands

This command has no related commands.

(config-rserver-redir) probe

To configure a probe to monitor the health of a real server, use the probe command. Use the no form of this command to remove the probe from the real server.

probe probe-name

no probe probe-name

Syntax Description


probe-name	Identifier of an existing probe that you want to assign to a real server to monitor its health. Enter an unquoted text string with no spaces and a maximum of 64 alphanumeric characters.

Command Modes

Real server redirect configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
A2(3.2). Not applicable for A4(1.0).	This command was introduced.


ACE Appliance Release	Modification
A3(2.7). Not applicable for A4(1.0).	This command was introduced.

Usage Guidelines

You can associate multiple probes with each real server.

You can only configure probes with an IP address in routed mode under a redirect server.

You cannot associate a scripted probe with a redirect server.

Examples

To configure a probe for a real server, enter:

host1/Admin(config-rserver-redir)# probe SERVER1_PROBE

To remove a probe from a real server, enter:

host1/Admin(config-rserver-redir)# no probe SERVER1_PROBE

Related Commands

(config-probe-probe_type) ip address

(config-rserver-redir) rate-limit

rate-limit {connection number1 | bandwidth number2}

no rate-limit {connection | bandwidth}

Syntax Description


connection number1	Specifies the real server connection-rate limit in connections per second. Enter an integer from 2 to 350000. There is no default value.
bandwidth number2	Specifies the real server bandwidth-rate limit in bytes per second. Enter an integer from 2 to 300000000. There is no default value.

Command Modes

Real server redirect configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
A2(1.0)	This command was introduced.


ACE Appliance Release	Modification
A3(1.0)	This command was introduced.

Usage Guidelines

You can also limit the connection rate and the bandwidth rate at the virtual server level in a connection parameter map. For details, see the Security Guide, Cisco ACE Application Control Engine.

Examples

To limit the connection rate of a real server to 100,000 connections per second, enter:

host1/Admin(config-rserver-redir)# rate-limit connection 100000

To revert to the ACE default of not limiting the real-server connection rate, enter:

host1/Admin(config-rserver-redir)# no rate-limit connection

To limit the real-server bandwidth rate to 5,000,000 bytes per second, enter:

host1/Admin(config-rserver-redir)# rate-limit bandwidth 5000000

To revert to the ACE default of not limiting real-server bandwidth, enter:

host1/Admin(config-rserver-redir)# no rate-limit bandwidth

Related Commands

(config-rserver-redir) conn-limit

(config-rserver-redir) webhost-redirection

To configure the relocation URL string used for redirection, use the webhost-redirection command. You can configure a port number to redirect a request in the relocation string. Use the no form of this command to remove the real server redirection URL string from the configuration.

webhost-redirection relocation_string [301 | 302]

no webhost-redirection

Syntax Description


relocation_string	URL string used to redirect requests to another server. Enter an unquoted text string with no spaces and a maximum of 255 alphanumeric characters. The redirection string supports the following special characters: •%h—Inserts the hostname from the request Host header •%p—Inserts the URL path string from the request Note To insert a question mark (?) in the relocation string, press Ctrl-v before you type the question mark.
[301 \| 302]	(Optional) Specifies the redirection status code returned to a client. The codes indicate the following: •301—The requested resource has been moved permanently. For future references to this resource, the client should use one of the returned URIs. •302—(Default) The requested resource has been found but has been moved temporarily to another location. For future references to this resource, the client should continue to use the request URI because the resource may be moved to other locations from time to time. For more information about redirection status codes, see RFC 2616.

Command Modes

Real server redirect configuration mode

Admin and user contexts

Command History


ACE Module Release	Modification
3.0(0)A1(2)	This command was introduced.


ACE Appliance Release	Modification
A1(7)	This command was introduced.

Usage Guidelines

Enter this command only on a real server that you have configured as a redirection server.

Examples

To configure a redirection string on a real server, enter:

host1/Admin(config-rserver-redir)# webhost-redirection www.acme.com/common/images/*.jpg 
301

To remove the redirection string from a real server, enter:

host1/Admin(config-rserver-redir)# no webhost-redirection

Related Commands

This command has no related commands.

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