VIRTUAL_HOST_WEIGHT does not provide a fail over for 503 about dockercloud-haproxy

[tifayuki]

The VIRTUAL_HOST_WEIGHTmerely has something to do with the order of HAProxy's ACL rules, which works very similar to the routing rules in IP table. Once a rule is hit, HAProxy always forward the request to the related backends. HAProxy doesn't check the response of the request and try another rules.

In your case, your last *.example.com container functions more like a response to 404, not 503.

To handle 503, you may need to check error file and errorloc here: https://cbonte.github.io/haproxy-dconv/configuration-1.5.html#4.2-errorfile

[modius]

Many thanks @tifayuki that makes a lot of sense. I'll take a look at errorloc.

[modius]

@tifayuki can't see where I would configure errorloc as an environment variable for dockercloud/haproxy.

Am guessing that EXTRA_SETTINGS is the right environment variable to be putting this into, but can't seem to get the following to work:

EXTRA_SETTINGS=errorloc503 503 http://mysite.com/503.html

Am I on the right track?

[tifayuki]

Yes, setting EXTRA_SETTINGS=errorloc303 503 http://mysite.com/503.html will work.

There is no errorloc503, but errorloc302 and errorloc303