HAProxy Enterprise Documentation 2.7r1

add server

Add a dynamic server to a backend.

Description

Instantiate a new server attached to an existing backend. Such a server may also be called a dynamic server.

The specified server name must not already be in use in the backend. The backend must be configured to use a dynamic load-balancing algorithm for the balance directive: roundrobin, leastconn, first, or random.

A dynamic server is not restored after a proxy reload operation. If you need the server definition to persist, add it to the HAProxy Enterprise configuration file.

Dynamic servers are statically initialized with the none init-addr method. In this method, the server starts in the down state without a valid IP address.

It may be possible to reach the fd (file descriptor) limit when using a large number of dynamic servers. See also fd-hard-limit and ulimit-n in the global keyword documentation.

The following keywords are supported for configuring the new server:

Keyword

Note

agent-addr

agent-check

Even when enabled by this keyword, agent check is still inactive until activated independently of the server with the enable agent command. Note that in this case the server may be activated via the agent depending on the status reported, without an explicit enable server command. This also means that extra care is required when removing a dynamic server with agent check. The agent should first be deactivated using disable agent to be able to put the server in the required maintenance mode before removal.

agent-inter

agent-port

agent-send

allow-0rtt

alpn

addr

backup

ca-file

check

Even when enabled by this keyword, health check is still inactive until activated independently of the server with the enable health command.

check-alpn

check-proto

check-send-proxy

check-sni

check-ssl

check-via-socks4

ciphers

ciphersuites

crl-file

crt

disabled

downinter

enabled

error-limit

fall

fastinter

force-sslv3/tlsv10/tlsv11/tlsv12/tlsv13

id

inter

maxconn

maxqueue

minconn

no-ssl-reuse

no-sslv3/tlsv10/tlsv11/tlsv12/tlsv13

no-tls-tickets

npn

observe

on-error

on-marked-down

on-marked-up

pool-low-conn

pool-max-conn

pool-purge-delay

port

proto

proxy-v2-options

rise

send-proxy

send-proxy-v2

send-proxy-v2-ssl

send-proxy-v2-ssl-cn

slowstart

sni

source

ssl

ssl-max-ver

ssl-min-ver

tfo

tls-tickets

track

A dynamic server may use this keyword to follow the check status of another server from the configuration. However, it is not possible to track another dynamic server. This restriction ensures that the tracking chain is kept consistent in the event a dynamic server is deleted.

usesrc

verify

verifyhost

weight

ws

For syntax details, see Server configuration.

Servers added with this command can be deleted using the del server command.

Examples

Below, we add the server server2 to backend be_test:

$ echo "add server be_test/server2 enabled maxconn=1000" | \
   sudo socat stdio unix-connect:/var/run/hapee-2.7/hapee-lb.sock

See also

Next up

add ssl ca-file