Forum Discussion

John_Adams's avatar
John_Adams
Icon for Nimbostratus rankNimbostratus
Jun 06, 2023
Solved

Redirecting to an external site when the internal site is down

Hi, folks,      I've read several articles with iRules for redirection and think I understand that part of my problem, but I've seen nothing about how to trigger the redirection when the local site ...
application delivery
  • Paulius's avatar
    Paulius
    Jun 06, 2023

    John_Adams It seems like we cannot use a variable that has been created in that section of code. You can try the following to see if this works for you.

    when HTTP_REQUEST priority 500 {

    if { [active_members [LB::server pool]] == 0 } {
        HTTP::respond 307 content {
            <html>
            <head>
            <title>Apology Page</title>
            </head>
            <body>
            We are sorry, but the site you are looking for is temporarily out of service<br>
            If you feel you have reached this page in error, please try again.
            </body>
            </html>
        }
    }

}
John_Adams's avatar
John_Adams
Icon for Nimbostratus rankNimbostratus

Hi, Paulius,

     I've tried to implement this more or less as is:

when CLIENT_ACCEPTED {

             set DEFAULT_POOL [LB::server pool]

}

when HTTP_REQUEST {

          if { [active_members [${DEFAULT_POOL}]] == 0 } {
                   HTTP::respond 307 content {
<html>
<head>
<title>Apology Page</title>
</head>
<body>
We are sorry, but the site you are looking for is temporarily out of service<br>
If you feel you have reached this page in error, please try again.
</body>
</html>
                   }
          }

}

and I am getting an interesting error:

tmm1[12440]: 01220001:3: TCL error: /Common/_ualr_hostdown_307 <HTTP_REQUEST> - invalid command name "/Common/<app name>/<pool name>"     while executing "${DEFAULT_POOL}"

     I'm also getting it when I switch to the "Temporary Redirect <URL>" code you presented. Any thoughts?

Thanks,

     John A

Paulius's avatar
Paulius
Icon for MVP rankMVP
Jun 06, 2023

John_Adams It seems like we cannot use a variable that has been created in that section of code. You can try the following to see if this works for you.

when HTTP_REQUEST priority 500 {

    if { [active_members [LB::server pool]] == 0 } {
        HTTP::respond 307 content {
            <html>
            <head>
            <title>Apology Page</title>
            </head>
            <body>
            We are sorry, but the site you are looking for is temporarily out of service<br>
            If you feel you have reached this page in error, please try again.
            </body>
            </html>
        }
    }

}
  • John_Adams's avatar
    John_Adams
    Icon for Nimbostratus rankNimbostratus
    Jun 06, 2023

    Paulius, I'm now getting no errors and the apology text in Safari, Firefox, and Chrome, which is clear progress and fulfills my specific task.

    One oddity: When I tried the "Temporary Redirect <URL>" code you offered, I get no errors and blank screens with all browsers. It's throwing up that apology message that I've been asked to do, but I'm still curious about the other syntax and why it's not working. It seems very straightforward and I don't believe I have any typos.

    • Paulius's avatar
      Paulius
      Icon for MVP rankMVP
      Jun 07, 2023

      John_Adams My mistake on this one. Because you're wanting the F5 to serve a generic website you should do the following instead of a 307. You would use the redirect if you were sending a new URL to the client but in this case you are sending a basic website.

      when HTTP_REQUEST priority 500 {

    if { [active_members [LB::server pool]] == 0 } {
        HTTP::respond 200 content {
            <html>
            <head>
            <title>Apology Page</title>
            </head>
            <body>
            We are sorry, but the site you are looking for is temporarily out of service<br>
            If you feel you have reached this page in error, please try again.
            </body>
            </html>
        }
    }

}