Forum Discussion
Ross_Fitheridge
Nimbostratus
Nimbostratusincrement pointer in array
I am trying to redirect to one of any hosts, to give some form of basic load balancing, like round robin, otherwise it goes to the default pool.
I guess I need an array and a pointer to increment each time the redirect gets executed, and I want it to go back to the top of the array once it has reached the bottom. What I have written to give you the gist is:
when RULE_INIT {
list of hosts to redirect to sequentially
set ibewebserver [ list \
"ww1" \
"ww2" \
"ww3" \
]
}
when HTTP_REQUEST {
if { [findstr [HTTP::uri] "/" 1 "/"] equals "oldwebsite" } {
set $ibewebserver + 1
HTTP::redirect https://$ibewebserver.acme.com[HTTP::uri]
}
}
Another problem I have with this iRule is matching case, the "oldwebsite" sometimes is in uppercase, mixed case, and I keep finding oddities.
It seems really simple and I feel ashamed to ask, but I'm not a programmer, and looking through the forum and references I have not seen anything quite like it. I know I am way off the trail, but you will make a novice very happy.
RossF
1 Reply
Ross_Fitheridgethanks Joe,
I made it slightly to simple for you. My hostnames, are just random names. The uri, is actually what I am testing on. Not sure if its optimal but it works. I just need to think about how to deal with the remote hosts being off-line.
when RULE_INIT {
list of hosts to redirect to sequentially
set ::HOSTNAME [list \
pluto \
saturn \
]
set number of hosts as in list.
set ::HOST_NUM [llength $::HOSTNAME]
set number of hosts one less than in list, why? list index starts at zero.
incr ::HOST_NUM -1
initialize a global variable with index 0
set ::REDIR_NUM 0
}
when HTTP_REQUEST {
Send to Content only available on Redbus www.acme.de direct to server
Jobs
if { [findstr [string tolower [HTTP::uri] ] "/acmeonline/de/" 15 "/"] equals "jobs.nsf" } {
if global index is greater than hostnum, reset it to zero
if { $::REDIR_NUM > $::HOST_NUM } {
set ::REDIR_NUM 0
}
HTTP::redirect https://[lindex $::HOSTNAME $::REDIR_NUM].rent-at-acme.com[HTTP::uri]
increment the global index
incr ::REDIR_NUM
RetroClaim
} elseif { [findstr [string tolower [HTTP::uri] ] "/acmeonline/" 12 "/"] equals "retroclaim.nsf" } {
if global index is greater than hostnum, reset it to zero
if { $::REDIR_NUM > $::HOST_NUM } {
set ::REDIR_NUM 0
}
HTTP::redirect https://[lindex $::HOSTNAME $::REDIR_NUM].rent-at-acme.com[HTTP::uri]
increment the global index
incr ::REDIR_NUM
Send www.acme.de to the Proxy Cache virtual servers.
} elseif { [HTTP::host] equals "www.acme.de"} {
snat none
pool Cache_Server_Pool
......some additonal conditions................
If there is anything else left then send to default.
}
}
