We need four static offline pages - planned maintenance for apache, unplanned outage for apache, planned maintenance for haproxy and unplanned outage for haproxy. The format of the haproxy page is described here:
http://haproxy.1wt.eu/download/1.3/doc/configuration.txt
" The files are returned verbatim on the TCP socket. This allows any trick such
as redirections to another URL or site, as well as tricks to clean cookies,
force enable or disable caching, etc... The package provides default error
files returning the same contents as default errors.
The files should not exceed the configured buffer size (BUFSIZE), which
generally is 8 or 16 kB, otherwise they will be truncated. It is also wise
not to put any reference to local contents (eg: images) in order to avoid
loops between the client and HAProxy when all servers are down, causing an
error to be returned instead of an image. For better HTTP compliance, it is
recommended that all header lines end with CR-LF and not LF alone.
The files are read at the same time as the configuration and kept in memory.
For this reason, the errors continue to be returned even when the process is
chrooted, and no file change is considered while the process is running. A
simple method for developing those files consists in associating them to the
403 status code and interrogating a blocked URL."
I've added the offline-unplanned file from LP for haproxy.
When this bug is fixed, LOSAs will want to work on RT#36817