2

I wonder whether there is a way to configure a default backend in haproxy, so it balances requests among a pool of backend servers (three in the example below), keeping the default backend as a failover, only in case the three main backends are down.

It should be something like this:

  server backend-0 10.10.10.0:3000 check
  server backend-1 10.10.10.1:3100 check
  server backend-2 10.10.10.2:3200 check
  server backend-default 10.10.10.3:3300 check

I have tried setting a weight 0 in the backend-default, but that completely removes the server from the balancing algorithm.

2

Kind of - it is called "backup":

server backend-default 10.10.10.3:3300 check inter 5000 rise 1 fall 3 backup

From the haproxy docs:

Since version 1.1.17, it is possible to specify backup servers. These servers are only sollicited when no other server is available. This may only be useful to serve a maintenance page, or define one active and one backup server (seldom used in TCP mode). To make a server a backup one, simply add the 'backup' option on its line. These servers also support cookies, so if a cookie is specified for a backup server, clients assigned to this server will stick to it even when the other ones come back. Conversely, if no cookie is assigned to such a server, the clients will get their cookies removed (empty cookie = removal), and will be balanced against other servers once they come back. Please note that there is no load-balancing among backup servers by default. If there are several backup servers, the second one will only be used when the first one dies, and so on. To force load-balancing between backup servers, specify the 'allbackups' option.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.