Mailing List Archive

Backend Fetch failed
Not sure what is causing this error any help would be appreciated

Error 503 Backend Fetch Failed

Here is a copy of default.vcl


# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and https://www.varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;

# Default backend definition. Set this to point to your content server.
import std;

backend drupal {
.host = "drupal.miat.co";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "drupal.miat.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}


backend ncwrite {
.host = "ncwrite.miat.co";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "ncwrite.miat.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}




backend measurementinc {
.host = "www.measurementinc.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.measurementinc.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwriting {
.host = "www.pegwriting.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriting.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwritingscholar {
.host = "www.pegwritingscholar.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriitingscholar.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend utahcompose {
.host = "www.utahcompose.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.utahcompose.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend wpponline {
.host = "www.wpponline.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.wpponline.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend support {
.host = "support.wpponline.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.wpponline.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportpw {
.host = "support.pegwriting.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwriting.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}



backend supportpws {
.host = "support.pegwritingscholar.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwritingscholar.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportncw {
.host = "support.ncwrite.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.ncwrite.com";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportutc {
.host = "support.utahcompose.com";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.utahcompose";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}


}




sub vcl_recv {
if (req.http.host == "drupal.miat.co"){
set req.backend_hint = drupal;
} else if (req.http.host == "ncwrite.miat.co"){
set req.backend_hint = ncwrite;
} else if (req.http.host == "www.measurementinc.com"){
set req.backend_hint = measurementinc;
} else if (req.http.host == "www.pegwriting.com"){
set req.backend_hint = pegwriting;
} else if (req.http.host == "pegwritingscholar.com"){
set req.backend_hint = pegwritingscholar;
} else if (req.http.host == "www.utahcompose.com"){
set req.backend_hint = utahcompose;
} else if (req.http.host == "www.wpponline.com"){
set req.backend_hint = wpponline;
} else if (req.http.host == "<^(?=.*?\bsupport\b)(?=.*?\bwpponline\b)(?=.*?\bcom\b).*$>"){
set req.backend_hint = support;
} else if (req.http.host == "<^(?=.*?\bsupport\b)(?=.*?\bpegwriting\b)(?=.*?\bcom\b).*$>"){
set req.backend_hint = supportpw;
} else if (req.http.host == "<^(?=.*?\bsupport\b)(?=.*?\bpegwritingscholar\b)(?=.*?\bcom\b).*$>"){
set req.backend_hint = supportpws;
} else if (req.http.host == "<^(?=.*?\bsupport\b)(?=.*?\bncwrite\b)(?=.*?\bcom\b).*$>"){
set req.backend_hint = supportncw;
} else if (req.http.host == "<^(?=.*?\bsupport\b)(?=.*?\butahcompose\b)(?=.*?\bcom\b).*$>"){
set req.backend_hint = supportutc;
return (hash);
}
}


#sub vcl_pass {





sub vcl_backend_response {
set beresp.grace = 6h;
set beresp.ttl = 5m;
}









sub vcl_deliver {
# Happens when we have all the pieces we need, and are about to send the
# response to the client.
#
# You can do accounting or modifying the final object here.
}



This email (including any attachments) may contain confidential information intended solely for acknowledged recipients. If you think you have received this information in error, please reply to the sender and delete all copies from your system. Please note that unauthorized use, disclosure, or further distribution of this information is prohibited by the sender. Note also that we may monitor email directed to or originating from our network. Thank you for your consideration and assistance. |
Re: Backend Fetch failed [ In reply to ]
Can be anything, really, care to share a varnishlog?

--
Guillaume Quintard

On Wed, Apr 5, 2017 at 8:46 PM, Rodney Bizzell <rbizzell@measinc.com> wrote:

> Not sure what is causing this error any help would be appreciated
>
>
>
> Error 503 Backend Fetch Failed
>
>
>
> Here is a copy of default.vcl
>
>
>
>
>
> # This is an example VCL file for Varnish.
>
> #
>
> # It does not do anything by default, delegating control to the
>
> # builtin VCL. The builtin VCL is called when there is no explicit
>
> # return statement.
>
> #
>
> # See the VCL chapters in the Users Guide at
> https://www.varnish-cache.org/docs/
>
> # and https://www.varnish-cache.org/trac/wiki/VCLExamples for more
> examples.
>
>
>
> # Marker to tell the VCL compiler that this VCL has been adapted to the
>
> # new 4.0 format.
>
> vcl 4.0;
>
>
>
> # Default backend definition. Set this to point to your content server.
>
> import std;
>
>
>
> backend drupal {
>
> .host = "drupal.miat.co";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "drupal.miat.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
>
>
> backend ncwrite {
>
> .host = "ncwrite.miat.co";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "ncwrite.miat.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
>
>
>
>
>
>
> backend measurementinc {
>
> .host = "www.measurementinc.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "www.measurementinc.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend pegwriting {
>
> .host = "www.pegwriting.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "www.pegwriting.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend pegwritingscholar {
>
> .host = "www.pegwritingscholar.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "www.pegwriitingscholar.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend utahcompose {
>
> .host = "www.utahcompose.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "www.utahcompose.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend wpponline {
>
> .host = "www.wpponline.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "www.wpponline.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend support {
>
> .host = "support.wpponline.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "support.wpponline.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend supportpw {
>
> .host = "support.pegwriting.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "support.pegwriting.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
>
>
>
>
> backend supportpws {
>
> .host = "support.pegwritingscholar.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "support.pegwritingscholar.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend supportncw {
>
> .host = "support.ncwrite.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "support.ncwrite.com";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
> }
>
>
>
> backend supportutc {
>
> .host = "support.utahcompose.com";
>
> .port = "80";
>
> .connect_timeout = 6000s;
>
> .first_byte_timeout = 6000s;
>
> .between_bytes_timeout = 6000s;
>
> .probe = {
>
> .url = "support.utahcompose";
>
> .timeout = 60ms;
>
> .interval = 1s;
>
> .window = 10;
>
> .threshold = 8;
>
> }
>
>
>
>
>
> }
>
>
>
>
>
>
>
>
>
> sub vcl_recv {
>
> if (req.http.host == "drupal.miat.co"){
>
> set req.backend_hint = drupal;
>
> } else if (req.http.host == "ncwrite.miat.co"){
>
> set req.backend_hint = ncwrite;
>
> } else if (req.http.host == "www.measurementinc.com"){
>
> set req.backend_hint = measurementinc;
>
> } else if (req.http.host == "www.pegwriting.com"){
>
> set req.backend_hint = pegwriting;
>
> } else if (req.http.host == "pegwritingscholar.com"){
>
> set req.backend_hint = pegwritingscholar;
>
> } else if (req.http.host == "www.utahcompose.com"){
>
> set req.backend_hint = utahcompose;
>
> } else if (req.http.host == "www.wpponline.com"){
>
> set req.backend_hint = wpponline;
>
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bwpponline\b)(?=.*?\bcom\b).*$»"){
>
> set req.backend_hint = support;
>
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bpegwriting\b)(?=.*?\bcom\b).*$»"){
>
> set req.backend_hint = supportpw;
>
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bpegwritingscholar\b)(?=.*?\bcom\b).*$»"){
>
> set req.backend_hint = supportpws;
>
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bncwrite\b)(?=.*?\bcom\b).*$»"){
>
> set req.backend_hint = supportncw;
>
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> butahcompose\b)(?=.*?\bcom\b).*$»"){
>
> set req.backend_hint = supportutc;
>
> return (hash);
>
> }
>
> }
>
>
>
>
>
> #sub vcl_pass {
>
>
>
>
>
>
>
>
>
>
>
> sub vcl_backend_response {
>
> set beresp.grace = 6h;
>
> set beresp.ttl = 5m;
>
> }
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> sub vcl_deliver {
>
> # Happens when we have all the pieces we need, and are about to send
> the
>
> # response to the client.
>
> #
>
> # You can do accounting or modifying the final object here.
>
> }
>
>
>
>
> This email (including any attachments) may contain confidential
> information intended solely for acknowledged recipients. If you think you
> have received this information in error, please reply to the sender and
> delete all copies from your system. Please note that unauthorized use,
> disclosure, or further distribution of this information is prohibited by
> the sender. Note also that we may monitor email directed to or originating
> from our network. Thank you for your consideration and assistance. |
>
> _______________________________________________
> varnish-misc mailing list
> varnish-misc@varnish-cache.org
> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>
RE: Backend Fetch failed [ In reply to ]
When I issue the varnishlog and varnishncsa command nothing happens. I am not using Apache I am caching IIS servers.
From: Guillaume Quintard [mailto:guillaume@varnish-software.com]
Sent: Thursday, April 06, 2017 3:12 AM
To: Rodney Bizzell <rbizzell@measinc.com>
Cc: varnish-misc@varnish-cache.org
Subject: Re: Backend Fetch failed

Can be anything, really, care to share a varnishlog?

--
Guillaume Quintard

On Wed, Apr 5, 2017 at 8:46 PM, Rodney Bizzell <rbizzell@measinc.com<mailto:rbizzell@measinc.com>> wrote:
Not sure what is causing this error any help would be appreciated

Error 503 Backend Fetch Failed

Here is a copy of default.vcl


# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and https://www.varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;

# Default backend definition. Set this to point to your content server.
import std;

backend drupal {
.host = "drupal.miat.co<http://drupal.miat.co>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "drupal.miat.com<http://drupal.miat.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}


backend ncwrite {
.host = "ncwrite.miat.co<http://ncwrite.miat.co>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "ncwrite.miat.com<http://ncwrite.miat.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}




backend measurementinc {
.host = "www.measurementinc.com<http://www.measurementinc.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.measurementinc.com<http://www.measurementinc.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwriting {
.host = "www.pegwriting.com<http://www.pegwriting.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriting.com<http://www.pegwriting.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwritingscholar {
.host = "www.pegwritingscholar.com<http://www.pegwritingscholar.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriitingscholar.com<http://www.pegwriitingscholar.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend utahcompose {
.host = "www.utahcompose.com<http://www.utahcompose.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.utahcompose.com<http://www.utahcompose.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend wpponline {
.host = "www.wpponline.com<http://www.wpponline.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.wpponline.com<http://www.wpponline.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend support {
.host = "support.wpponline.com<http://support.wpponline.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.wpponline.com<http://support.wpponline.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportpw {
.host = "support.pegwriting.com<http://support.pegwriting.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwriting.com<http://support.pegwriting.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}



backend supportpws {
.host = "support.pegwritingscholar.com<http://support.pegwritingscholar.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwritingscholar.com<http://support.pegwritingscholar.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportncw {
.host = "support.ncwrite.com<http://support.ncwrite.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.ncwrite.com<http://support.ncwrite.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportutc {
.host = "support.utahcompose.com<http://support.utahcompose.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.utahcompose";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}


}




sub vcl_recv {
if (req.http.host == "drupal.miat.co<http://drupal.miat.co>"){
set req.backend_hint = drupal;
} else if (req.http.host == "ncwrite.miat.co<http://ncwrite.miat.co>"){
set req.backend_hint = ncwrite;
} else if (req.http.host == "www.measurementinc.com<http://www.measurementinc.com>"){
set req.backend_hint = measurementinc;
} else if (req.http.host == "www.pegwriting.com<http://www.pegwriting.com>"){
set req.backend_hint = pegwriting;
} else if (req.http.host == "pegwritingscholar.com<http://pegwritingscholar.com>"){
set req.backend_hint = pegwritingscholar;
} else if (req.http.host == "www.utahcompose.com<http://www.utahcompose.com>"){
set req.backend_hint = utahcompose;
} else if (req.http.host == "www.wpponline.com<http://www.wpponline.com>"){
set req.backend_hint = wpponline;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bwpponline\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = support;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bpegwriting\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportpw;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bpegwritingscholar\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportpws;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bncwrite\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportncw;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\butahcompose\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportutc;
return (hash);
}
}


#sub vcl_pass {





sub vcl_backend_response {
set beresp.grace = 6h;
set beresp.ttl = 5m;
}









sub vcl_deliver {
# Happens when we have all the pieces we need, and are about to send the
# response to the client.
#
# You can do accounting or modifying the final object here.
}



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RE: Backend Fetch failed [ In reply to ]
I will attach the logs I found them

From: Guillaume Quintard [mailto:guillaume@varnish-software.com]
Sent: Thursday, April 06, 2017 3:12 AM
To: Rodney Bizzell <rbizzell@measinc.com>
Cc: varnish-misc@varnish-cache.org
Subject: Re: Backend Fetch failed

Can be anything, really, care to share a varnishlog?

--
Guillaume Quintard

On Wed, Apr 5, 2017 at 8:46 PM, Rodney Bizzell <rbizzell@measinc.com<mailto:rbizzell@measinc.com>> wrote:
Not sure what is causing this error any help would be appreciated

Error 503 Backend Fetch Failed

Here is a copy of default.vcl


# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and https://www.varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;

# Default backend definition. Set this to point to your content server.
import std;

backend drupal {
.host = "drupal.miat.co<http://drupal.miat.co>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "drupal.miat.com<http://drupal.miat.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}


backend ncwrite {
.host = "ncwrite.miat.co<http://ncwrite.miat.co>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "ncwrite.miat.com<http://ncwrite.miat.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}




backend measurementinc {
.host = "www.measurementinc.com<http://www.measurementinc.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.measurementinc.com<http://www.measurementinc.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwriting {
.host = "www.pegwriting.com<http://www.pegwriting.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriting.com<http://www.pegwriting.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwritingscholar {
.host = "www.pegwritingscholar.com<http://www.pegwritingscholar.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriitingscholar.com<http://www.pegwriitingscholar.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend utahcompose {
.host = "www.utahcompose.com<http://www.utahcompose.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.utahcompose.com<http://www.utahcompose.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend wpponline {
.host = "www.wpponline.com<http://www.wpponline.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.wpponline.com<http://www.wpponline.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend support {
.host = "support.wpponline.com<http://support.wpponline.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.wpponline.com<http://support.wpponline.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportpw {
.host = "support.pegwriting.com<http://support.pegwriting.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwriting.com<http://support.pegwriting.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}



backend supportpws {
.host = "support.pegwritingscholar.com<http://support.pegwritingscholar.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwritingscholar.com<http://support.pegwritingscholar.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportncw {
.host = "support.ncwrite.com<http://support.ncwrite.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.ncwrite.com<http://support.ncwrite.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportutc {
.host = "support.utahcompose.com<http://support.utahcompose.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.utahcompose";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}


}




sub vcl_recv {
if (req.http.host == "drupal.miat.co<http://drupal.miat.co>"){
set req.backend_hint = drupal;
} else if (req.http.host == "ncwrite.miat.co<http://ncwrite.miat.co>"){
set req.backend_hint = ncwrite;
} else if (req.http.host == "www.measurementinc.com<http://www.measurementinc.com>"){
set req.backend_hint = measurementinc;
} else if (req.http.host == "www.pegwriting.com<http://www.pegwriting.com>"){
set req.backend_hint = pegwriting;
} else if (req.http.host == "pegwritingscholar.com<http://pegwritingscholar.com>"){
set req.backend_hint = pegwritingscholar;
} else if (req.http.host == "www.utahcompose.com<http://www.utahcompose.com>"){
set req.backend_hint = utahcompose;
} else if (req.http.host == "www.wpponline.com<http://www.wpponline.com>"){
set req.backend_hint = wpponline;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bwpponline\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = support;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bpegwriting\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportpw;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bpegwritingscholar\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportpws;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\bncwrite\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportncw;
} else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\butahcompose\b)(?=.*?\bcom\b).*$»"){
set req.backend_hint = supportutc;
return (hash);
}
}


#sub vcl_pass {





sub vcl_backend_response {
set beresp.grace = 6h;
set beresp.ttl = 5m;
}









sub vcl_deliver {
# Happens when we have all the pieces we need, and are about to send the
# response to the client.
#
# You can do accounting or modifying the final object here.
}



This email (including any attachments) may contain confidential information intended solely for acknowledged recipients. If you think you have received this information in error, please reply to the sender and delete all copies from your system. Please note that unauthorized use, disclosure, or further distribution of this information is prohibited by the sender. Note also that we may monitor email directed to or originating from our network. Thank you for your consideration and assistance. |

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Re: Backend Fetch failed [ In reply to ]
<< BeReq >> 65547
- Begin bereq 65546 pass
- Timestamp Start: 1491485655.912819 0.000000 0.000000
- BereqMethod GET
- BereqURL /
- BereqProtocol HTTP/1.1
- BereqHeader Host: ncwrite.miat.co
- BereqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
- BereqHeader Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
- BereqHeader Accept-Language: en-US,en;q=0.5
- BereqHeader Accept-Encoding: gzip, deflate
- BereqHeader Cookie: has_js=1
- BereqHeader Upgrade-Insecure-Requests: 1
- BereqHeader X-Forwarded-For: 172.16.5.21
- BereqHeader X-Varnish: 65547
- VCL_call BACKEND_FETCH
- VCL_return fetch
- FetchError no backend connection
- Timestamp Beresp: 1491485655.912871 0.000051 0.000051
- Timestamp Error: 1491485655.912878 0.000059 0.000007
- BerespProtocol HTTP/1.1
- BerespStatus 503
- BerespReason Service Unavailable
- BerespReason Backend fetch failed
- BerespHeader Date: Thu, 06 Apr 2017 13:34:15 GMT
- BerespHeader Server: Varnish
- VCL_call BACKEND_ERROR
- BerespHeader Content-Type: text/html; charset=utf-8
- BerespHeader Retry-After: 5
- VCL_return deliver
- Storage malloc Transient
- ObjProtocol HTTP/1.1
- ObjStatus 503
- ObjReason Backend fetch failed
- ObjHeader Date: Thu, 06 Apr 2017 13:34:15 GMT
- ObjHeader Server: Varnish
- ObjHeader Content-Type: text/html; charset=utf-8
- ObjHeader Retry-After: 5
- Length 282
- BereqAcct 0 0 0 0 0 0
- End

* << Request >> 65546
- Begin req 65545 rxreq
- Timestamp Start: 1491485655.912700 0.000000 0.000000
- Timestamp Req: 1491485655.912700 0.000000 0.000000
- ReqStart 172.16.5.21 55234
- ReqMethod GET
- ReqURL /
- ReqProtocol HTTP/1.1
- ReqHeader Host: ncwrite.miat.co
- ReqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
- ReqHeader Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
- ReqHeader Accept-Language: en-US,en;q=0.5
- ReqHeader Accept-Encoding: gzip, deflate
- ReqHeader Cookie: has_js=1
- ReqHeader Connection: keep-alive
- ReqHeader Upgrade-Insecure-Requests: 1
- ReqHeader X-Forwarded-For: 172.16.5.21
- VCL_call RECV
- VCL_return pass
- VCL_call HASH
- VCL_return lookup
- VCL_call PASS
- VCL_return fetch
- Link bereq 65547 pass
- Timestamp Fetch: 1491485655.913049 0.000349 0.000349
- RespProtocol HTTP/1.1
- RespStatus 503
- RespReason Backend fetch failed
- RespHeader Date: Thu, 06 Apr 2017 13:34:15 GMT
- RespHeader Server: Varnish
- RespHeader Content-Type: text/html; charset=utf-8
- RespHeader Retry-After: 5
- RespHeader X-Varnish: 65546
- RespHeader Age: 0
- RespHeader Via: 1.1 varnish (Varnish/5.1)
- VCL_call DELIVER
- VCL_return deliver
- Timestamp Process: 1491485655.913070 0.000370 0.000021
- RespHeader Content-Length: 282
- Debug "RES_MODE 2"
- RespHeader Connection: keep-alive
- Timestamp Resp: 1491485655.913134 0.000433 0.000064
- ReqAcct 337 0 337 250 282 532
- End

* << Request >> 5
- Begin req 4 rxreq
- Timestamp Start: 1491485659.606174 0.000000 0.000000
- Timestamp Req: 1491485659.606174 0.000000 0.000000
- ReqStart 172.16.5.21 55235
- ReqMethod GET
- ReqURL /
- ReqProtocol HTTP/1.1
- ReqHeader Host: drupal.miat.co
- ReqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
- ReqHeader Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
- ReqHeader Accept-Language: en-US,en;q=0.5
- ReqHeader Accept-Encoding: gzip, deflate
- ReqHeader Cookie: has_js=1
- ReqHeader Connection: keep-alive
- ReqHeader Upgrade-Insecure-Requests: 1
- ReqHeader X-Forwarded-For: 172.16.5.21
- VCL_call RECV
- VCL_return pass
- VCL_call HASH
- VCL_return lookup
- VCL_call PASS
- VCL_return fetch
- Link bereq 6 pass
- Timestamp Fetch: 1491485659.606469 0.000295 0.000295
- RespProtocol HTTP/1.1
- RespStatus 503
- RespReason Backend fetch failed
- RespHeader Date: Thu, 06 Apr 2017 13:34:19 GMT
- RespHeader Server: Varnish
- RespHeader Content-Type: text/html; charset=utf-8
- RespHeader Retry-After: 5
- RespHeader X-Varnish: 5
- RespHeader Age: 0
- RespHeader Via: 1.1 varnish (Varnish/5.1)
- VCL_call DELIVER
- VCL_return deliver
- Timestamp Process: 1491485659.606486 0.000311 0.000017
- RespHeader Content-Length: 278
- Debug "RES_MODE 2"
- RespHeader Connection: keep-alive
- Timestamp Resp: 1491485659.606557 0.000382 0.000071
- ReqAcct 336 0 336 246 278 524
- End

* << BeReq >> 6
- Begin bereq 5 pass
- Timestamp Start: 1491485659.606284 0.000000 0.000000
- BereqMethod GET
- BereqURL /
- BereqProtocol HTTP/1.1
- BereqHeader Host: drupal.miat.co
- BereqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
- BereqHeader Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
- BereqHeader Accept-Language: en-US,en;q=0.5
- BereqHeader Accept-Encoding: gzip, deflate
- BereqHeader Cookie: has_js=1
- BereqHeader Upgrade-Insecure-Requests: 1
- BereqHeader X-Forwarded-For: 172.16.5.21
- BereqHeader X-Varnish: 6
- VCL_call BACKEND_FETCH
- VCL_return fetch
- FetchError no backend connection
- Timestamp Beresp: 1491485659.606340 0.000056 0.000056
- Timestamp Error: 1491485659.606347 0.000062 0.000006
- BerespProtocol HTTP/1.1
- BerespStatus 503
- BerespReason Service Unavailable
- BerespReason Backend fetch failed
- BerespHeader Date: Thu, 06 Apr 2017 13:34:19 GMT
- BerespHeader Server: Varnish
- VCL_call BACKEND_ERROR

Here is the varnish log

- BerespHeader Content-Type: text/html; charset=utf-8
- BerespHeader Retry-After: 5
- VCL_return deliver
- Storage malloc Transient
- ObjProtocol HTTP/1.1
- ObjStatus 503
- ObjReason Backend fetch failed
- ObjHeader Date: Thu, 06 Apr 2017 13:34:19 GMT
- ObjHeader Server: Varnish
- ObjHeader Content-Type: text/html; charset=utf-8
- ObjHeader Retry-After: 5
- Length 278
- BereqAcct 0 0 0 0 0 0
- End

* << Session >> 65545
- Begin sess 0 HTTP/1
- SessOpen 172.16.5.21 55234 :80 172.16.2.139 80 1491485655.912552 21
- Link req 65546 rxreq
- SessClose RX_TIMEOUT 5.004
- End

* << Session >> 4
- Begin sess 0 HTTP/1
- SessOpen 172.16.5.21 55235 :80 172.16.2.139 80 1491485659.606121 22
- Link req 5 rxreq
- SessClose RX_TIMEOUT 5.005
- End


________________________________
From: Guillaume Quintard <guillaume@varnish-software.com>
Sent: Thursday, April 6, 2017 3:11 AM
To: Rodney Bizzell
Cc: varnish-misc@varnish-cache.org
Subject: Re: Backend Fetch failed

Can be anything, really, care to share a varnishlog?

--
Guillaume Quintard

On Wed, Apr 5, 2017 at 8:46 PM, Rodney Bizzell <rbizzell@measinc.com<mailto:rbizzell@measinc.com>> wrote:
Not sure what is causing this error any help would be appreciated

Error 503 Backend Fetch Failed

Here is a copy of default.vcl


# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and https://www.varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;

# Default backend definition. Set this to point to your content server.
import std;

backend drupal {
.host = "drupal.miat.co<http://drupal.miat.co>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "drupal.miat.com<http://drupal.miat.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}


backend ncwrite {
.host = "ncwrite.miat.co<http://ncwrite.miat.co>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "ncwrite.miat.com<http://ncwrite.miat.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}




backend measurementinc {
.host = "www.measurementinc.com<http://www.measurementinc.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.measurementinc.com<http://www.measurementinc.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwriting {
.host = "www.pegwriting.com<http://www.pegwriting.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriting.com<http://www.pegwriting.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend pegwritingscholar {
.host = "www.pegwritingscholar.com<http://www.pegwritingscholar.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.pegwriitingscholar.com<http://www.pegwriitingscholar.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend utahcompose {
.host = "www.utahcompose.com<http://www.utahcompose.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.utahcompose.com<http://www.utahcompose.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend wpponline {
.host = "www.wpponline.com<http://www.wpponline.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "www.wpponline.com<http://www.wpponline.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend support {
.host = "support.wpponline.com<http://support.wpponline.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.wpponline.com<http://support.wpponline.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportpw {
.host = "support.pegwriting.com<http://support.pegwriting.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwriting.com<http://support.pegwriting.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}



backend supportpws {
.host = "support.pegwritingscholar.com<http://support.pegwritingscholar.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.pegwritingscholar.com<http://support.pegwritingscholar.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportncw {
.host = "support.ncwrite.com<http://support.ncwrite.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.ncwrite.com<http://support.ncwrite.com>";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}

}

backend supportutc {
.host = "support.utahcompose.com<http://support.utahcompose.com>";
.port = "80";
.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;
.probe = {
.url = "support.utahcompose";
.timeout = 60ms;
.interval = 1s;
.window = 10;
.threshold = 8;
}


}




sub vcl_recv {
if (req.http.host == "drupal.miat.co<http://drupal.miat.co>"){
set req.backend_hint = drupal;
} else if (req.http.host == "ncwrite.miat.co<http://ncwrite.miat.co>"){
set req.backend_hint = ncwrite;
} else if (req.http.host == "www.measurementinc.com<http://www.measurementinc.com>"){
set req.backend_hint = measurementinc;
} else if (req.http.host == "www.pegwriting.com<http://www.pegwriting.com>"){
set req.backend_hint = pegwriting;
} else if (req.http.host == "pegwritingscholar.com<http://pegwritingscholar.com>"){
set req.backend_hint = pegwritingscholar;
} else if (req.http.host == "www.utahcompose.com<http://www.utahcompose.com>"){
set req.backend_hint = utahcompose;
} else if (req.http.host == "www.wpponline.com<http://www.wpponline.com>"){
set req.backend_hint = wpponline;
} else if (req.http.host == "?^(?=.*?\bsupport\b)(?=.*?\bwpponline\b)(?=.*?\bcom\b).*$?"){
set req.backend_hint = support;
} else if (req.http.host == "?^(?=.*?\bsupport\b)(?=.*?\bpegwriting\b)(?=.*?\bcom\b).*$?"){
set req.backend_hint = supportpw;
} else if (req.http.host == "?^(?=.*?\bsupport\b)(?=.*?\bpegwritingscholar\b)(?=.*?\bcom\b).*$?"){
set req.backend_hint = supportpws;
} else if (req.http.host == "?^(?=.*?\bsupport\b)(?=.*?\bncwrite\b)(?=.*?\bcom\b).*$?"){
set req.backend_hint = supportncw;
} else if (req.http.host == "?^(?=.*?\bsupport\b)(?=.*?\butahcompose\b)(?=.*?\bcom\b).*$?"){
set req.backend_hint = supportutc;
return (hash);
}
}


#sub vcl_pass {





sub vcl_backend_response {
set beresp.grace = 6h;
set beresp.ttl = 5m;
}









sub vcl_deliver {
# Happens when we have all the pieces we need, and are about to send the
# response to the client.
#
# You can do accounting or modifying the final object here.
}



This email (including any attachments) may contain confidential information intended solely for acknowledged recipients. If you think you have received this information in error, please reply to the sender and delete all copies from your system. Please note that unauthorized use, disclosure, or further distribution of this information is prohibited by the sender. Note also that we may monitor email directed to or originating from our network. Thank you for your consideration and assistance. |

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_______________________________________________
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varnish-misc@varnish-cache.org
https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
Re: Backend Fetch failed [ In reply to ]
- BerespReason Service Unavailable

run varnishadm backend.list -p

your probes are reporting sick backends.

--
Guillaume Quintard

On Thu, Apr 6, 2017 at 3:38 PM, Rodney Bizzell <rbizzell@measinc.com> wrote:

> << BeReq >> 65547
> - Begin bereq 65546 pass
> - Timestamp Start: 1491485655.912819 0.000000 0.000000
> - BereqMethod GET
> - BereqURL /
> - BereqProtocol HTTP/1.1
> - BereqHeader Host: ncwrite.miat.co
> - BereqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64;
> rv:52.0) Gecko/20100101 Firefox/52.0
> - BereqHeader Accept: text/html,application/xhtml+
> xml,application/xml;q=0.9,*/*;q=0.8
> - BereqHeader Accept-Language: en-US,en;q=0.5
> - BereqHeader Accept-Encoding: gzip, deflate
> - BereqHeader Cookie: has_js=1
> - BereqHeader Upgrade-Insecure-Requests: 1
> - BereqHeader X-Forwarded-For: 172.16.5.21
> - BereqHeader X-Varnish: 65547
> - VCL_call BACKEND_FETCH
> - VCL_return fetch
> - FetchError no backend connection
> - Timestamp Beresp: 1491485655.912871 0.000051 0.000051
> - Timestamp Error: 1491485655.912878 0.000059 0.000007
> - BerespProtocol HTTP/1.1
> - BerespStatus 503
> - BerespReason Service Unavailable
> - BerespReason Backend fetch failed
> - BerespHeader Date: Thu, 06 Apr 2017 13:34:15 GMT
> - BerespHeader Server: Varnish
> - VCL_call BACKEND_ERROR
> - BerespHeader Content-Type: text/html; charset=utf-8
> - BerespHeader Retry-After: 5
> - VCL_return deliver
> - Storage malloc Transient
> - ObjProtocol HTTP/1.1
> - ObjStatus 503
> - ObjReason Backend fetch failed
> - ObjHeader Date: Thu, 06 Apr 2017 13:34:15 GMT
> - ObjHeader Server: Varnish
> - ObjHeader Content-Type: text/html; charset=utf-8
> - ObjHeader Retry-After: 5
> - Length 282
> - BereqAcct 0 0 0 0 0 0
> - End
>
> * << Request >> 65546
> - Begin req 65545 rxreq
> - Timestamp Start: 1491485655.912700 0.000000 0.000000
> - Timestamp Req: 1491485655.912700 0.000000 0.000000
> - ReqStart 172.16.5.21 55234
> - ReqMethod GET
> - ReqURL /
> - ReqProtocol HTTP/1.1
> - ReqHeader Host: ncwrite.miat.co
> - ReqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64;
> rv:52.0) Gecko/20100101 Firefox/52.0
> - ReqHeader Accept: text/html,application/xhtml+
> xml,application/xml;q=0.9,*/*;q=0.8
> - ReqHeader Accept-Language: en-US,en;q=0.5
> - ReqHeader Accept-Encoding: gzip, deflate
> - ReqHeader Cookie: has_js=1
> - ReqHeader Connection: keep-alive
> - ReqHeader Upgrade-Insecure-Requests: 1
> - ReqHeader X-Forwarded-For: 172.16.5.21
> - VCL_call RECV
> - VCL_return pass
> - VCL_call HASH
> - VCL_return lookup
> - VCL_call PASS
> - VCL_return fetch
> - Link bereq 65547 pass
> - Timestamp Fetch: 1491485655.913049 0.000349 0.000349
> - RespProtocol HTTP/1.1
> - RespStatus 503
> - RespReason Backend fetch failed
> - RespHeader Date: Thu, 06 Apr 2017 13:34:15 GMT
> - RespHeader Server: Varnish
> - RespHeader Content-Type: text/html; charset=utf-8
> - RespHeader Retry-After: 5
> - RespHeader X-Varnish: 65546
> - RespHeader Age: 0
> - RespHeader Via: 1.1 varnish (Varnish/5.1)
> - VCL_call DELIVER
> - VCL_return deliver
> - Timestamp Process: 1491485655.913070 0.000370 0.000021
> - RespHeader Content-Length: 282
> - Debug "RES_MODE 2"
> - RespHeader Connection: keep-alive
> - Timestamp Resp: 1491485655.913134 0.000433 0.000064
> - ReqAcct 337 0 337 250 282 532
> - End
>
> * << Request >> 5
> - Begin req 4 rxreq
> - Timestamp Start: 1491485659.606174 0.000000 0.000000
> - Timestamp Req: 1491485659.606174 0.000000 0.000000
> - ReqStart 172.16.5.21 55235
> - ReqMethod GET
> - ReqURL /
> - ReqProtocol HTTP/1.1
> - ReqHeader Host: drupal.miat.co
> - ReqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64;
> rv:52.0) Gecko/20100101 Firefox/52.0
> - ReqHeader Accept: text/html,application/xhtml+
> xml,application/xml;q=0.9,*/*;q=0.8
> - ReqHeader Accept-Language: en-US,en;q=0.5
> - ReqHeader Accept-Encoding: gzip, deflate
> - ReqHeader Cookie: has_js=1
> - ReqHeader Connection: keep-alive
> - ReqHeader Upgrade-Insecure-Requests: 1
> - ReqHeader X-Forwarded-For: 172.16.5.21
> - VCL_call RECV
> - VCL_return pass
> - VCL_call HASH
> - VCL_return lookup
> - VCL_call PASS
> - VCL_return fetch
> - Link bereq 6 pass
> - Timestamp Fetch: 1491485659.606469 0.000295 0.000295
> - RespProtocol HTTP/1.1
> - RespStatus 503
> - RespReason Backend fetch failed
> - RespHeader Date: Thu, 06 Apr 2017 13:34:19 GMT
> - RespHeader Server: Varnish
> - RespHeader Content-Type: text/html; charset=utf-8
> - RespHeader Retry-After: 5
> - RespHeader X-Varnish: 5
> - RespHeader Age: 0
> - RespHeader Via: 1.1 varnish (Varnish/5.1)
> - VCL_call DELIVER
> - VCL_return deliver
> - Timestamp Process: 1491485659.606486 0.000311 0.000017
> - RespHeader Content-Length: 278
> - Debug "RES_MODE 2"
> - RespHeader Connection: keep-alive
> - Timestamp Resp: 1491485659.606557 0.000382 0.000071
> - ReqAcct 336 0 336 246 278 524
> - End
>
> * << BeReq >> 6
> - Begin bereq 5 pass
> - Timestamp Start: 1491485659.606284 0.000000 0.000000
> - BereqMethod GET
> - BereqURL /
> - BereqProtocol HTTP/1.1
> - BereqHeader Host: drupal.miat.co
> - BereqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64;
> rv:52.0) Gecko/20100101 Firefox/52.0
> - BereqHeader Accept: text/html,application/xhtml+
> xml,application/xml;q=0.9,*/*;q=0.8
> - BereqHeader Accept-Language: en-US,en;q=0.5
> - BereqHeader Accept-Encoding: gzip, deflate
> - BereqHeader Cookie: has_js=1
> - BereqHeader Upgrade-Insecure-Requests: 1
> - BereqHeader X-Forwarded-For: 172.16.5.21
> - BereqHeader X-Varnish: 6
> - VCL_call BACKEND_FETCH
> - VCL_return fetch
> - FetchError no backend connection
> - Timestamp Beresp: 1491485659.606340 0.000056 0.000056
> - Timestamp Error: 1491485659.606347 0.000062 0.000006
> - BerespProtocol HTTP/1.1
> - BerespStatus 503
> - BerespReason Service Unavailable
> - BerespReason Backend fetch failed
> - BerespHeader Date: Thu, 06 Apr 2017 13:34:19 GMT
> - BerespHeader Server: Varnish
> - VCL_call BACKEND_ERROR
>
> Here is the varnish log
>
> - BerespHeader Content-Type: text/html; charset=utf-8
> - BerespHeader Retry-After: 5
> - VCL_return deliver
> - Storage malloc Transient
> - ObjProtocol HTTP/1.1
> - ObjStatus 503
> - ObjReason Backend fetch failed
> - ObjHeader Date: Thu, 06 Apr 2017 13:34:19 GMT
> - ObjHeader Server: Varnish
> - ObjHeader Content-Type: text/html; charset=utf-8
> - ObjHeader Retry-After: 5
> - Length 278
> - BereqAcct 0 0 0 0 0 0
> - End
>
> * << Session >> 65545
> - Begin sess 0 HTTP/1
> - SessOpen 172.16.5.21 55234 :80 172.16.2.139 80 1491485655.912552
> 21
> - Link req 65546 rxreq
> - SessClose RX_TIMEOUT 5.004
> - End
>
> * << Session >> 4
> - Begin sess 0 HTTP/1
> - SessOpen 172.16.5.21 55235 :80 172.16.2.139 80 1491485659.606121
> 22
> - Link req 5 rxreq
> - SessClose RX_TIMEOUT 5.005
> - End
>
>
> ________________________________
> From: Guillaume Quintard <guillaume@varnish-software.com>
> Sent: Thursday, April 6, 2017 3:11 AM
> To: Rodney Bizzell
> Cc: varnish-misc@varnish-cache.org
> Subject: Re: Backend Fetch failed
>
> Can be anything, really, care to share a varnishlog?
>
> --
> Guillaume Quintard
>
> On Wed, Apr 5, 2017 at 8:46 PM, Rodney Bizzell <rbizzell@measinc.com
> <mailto:rbizzell@measinc.com>> wrote:
> Not sure what is causing this error any help would be appreciated
>
> Error 503 Backend Fetch Failed
>
> Here is a copy of default.vcl
>
>
> # This is an example VCL file for Varnish.
> #
> # It does not do anything by default, delegating control to the
> # builtin VCL. The builtin VCL is called when there is no explicit
> # return statement.
> #
> # See the VCL chapters in the Users Guide at
> https://www.varnish-cache.org/docs/
> # and https://www.varnish-cache.org/trac/wiki/VCLExamples for more
> examples.
>
> # Marker to tell the VCL compiler that this VCL has been adapted to the
> # new 4.0 format.
> vcl 4.0;
>
> # Default backend definition. Set this to point to your content server.
> import std;
>
> backend drupal {
> .host = "drupal.miat.co<http://drupal.miat.co>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "drupal.miat.com<http://drupal.miat.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
>
> backend ncwrite {
> .host = "ncwrite.miat.co<http://ncwrite.miat.co>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "ncwrite.miat.com<http://ncwrite.miat.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
>
>
>
> backend measurementinc {
> .host = "www.measurementinc.com<http://www.measurementinc.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "www.measurementinc.com<http://www.measurementinc.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend pegwriting {
> .host = "www.pegwriting.com<http://www.pegwriting.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "www.pegwriting.com<http://www.pegwriting.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend pegwritingscholar {
> .host = "www.pegwritingscholar.com<http://www.pegwritingscholar.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "www.pegwriitingscholar.com<http://www.pegwriitingscholar.
> com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend utahcompose {
> .host = "www.utahcompose.com<http://www.utahcompose.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "www.utahcompose.com<http://www.utahcompose.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend wpponline {
> .host = "www.wpponline.com<http://www.wpponline.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "www.wpponline.com<http://www.wpponline.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend support {
> .host = "support.wpponline.com<http://support.wpponline.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "support.wpponline.com<http://support.wpponline.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend supportpw {
> .host = "support.pegwriting.com<http://support.pegwriting.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "support.pegwriting.com<http://support.pegwriting.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
>
>
> backend supportpws {
> .host = "support.pegwritingscholar.com<http://support.
> pegwritingscholar.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "support.pegwritingscholar.com<http://support.
> pegwritingscholar.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend supportncw {
> .host = "support.ncwrite.com<http://support.ncwrite.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "support.ncwrite.com<http://support.ncwrite.com>";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
> }
>
> backend supportutc {
> .host = "support.utahcompose.com<http://support.utahcompose.com>";
> .port = "80";
> .connect_timeout = 6000s;
> .first_byte_timeout = 6000s;
> .between_bytes_timeout = 6000s;
> .probe = {
> .url = "support.utahcompose";
> .timeout = 60ms;
> .interval = 1s;
> .window = 10;
> .threshold = 8;
> }
>
>
> }
>
>
>
>
> sub vcl_recv {
> if (req.http.host == "drupal.miat.co<http://drupal.miat.co>"){
> set req.backend_hint = drupal;
> } else if (req.http.host == "ncwrite.miat.co<http://ncwrite.miat.co
> >"){
> set req.backend_hint = ncwrite;
> } else if (req.http.host == "www.measurementinc.com<http:/
> /www.measurementinc.com>"){
> set req.backend_hint = measurementinc;
> } else if (req.http.host == "www.pegwriting.com<http://
> www.pegwriting.com>"){
> set req.backend_hint = pegwriting;
> } else if (req.http.host == "pegwritingscholar.com<http://
> pegwritingscholar.com>"){
> set req.backend_hint = pegwritingscholar;
> } else if (req.http.host == "www.utahcompose.com<http://
> www.utahcompose.com>"){
> set req.backend_hint = utahcompose;
> } else if (req.http.host == "www.wpponline.com<http://www.
> wpponline.com>"){
> set req.backend_hint = wpponline;
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bwpponline\b)(?=.*?\bcom\b).*$»"){
> set req.backend_hint = support;
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bpegwriting\b)(?=.*?\bcom\b).*$»"){
> set req.backend_hint = supportpw;
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bpegwritingscholar\b)(?=.*?\bcom\b).*$»"){
> set req.backend_hint = supportpws;
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> bncwrite\b)(?=.*?\bcom\b).*$»"){
> set req.backend_hint = supportncw;
> } else if (req.http.host == "«^(?=.*?\bsupport\b)(?=.*?\
> butahcompose\b)(?=.*?\bcom\b).*$»"){
> set req.backend_hint = supportutc;
> return (hash);
> }
> }
>
>
> #sub vcl_pass {
>
>
>
>
>
> sub vcl_backend_response {
> set beresp.grace = 6h;
> set beresp.ttl = 5m;
> }
>
>
>
>
>
>
>
>
>
> sub vcl_deliver {
> # Happens when we have all the pieces we need, and are about to send
> the
> # response to the client.
> #
> # You can do accounting or modifying the final object here.
> }
>
>
>
> This email (including any attachments) may contain confidential
> information intended solely for acknowledged recipients. If you think you
> have received this information in error, please reply to the sender and
> delete all copies from your system. Please note that unauthorized use,
> disclosure, or further distribution of this information is prohibited by
> the sender. Note also that we may monitor email directed to or originating
> from our network. Thank you for your consideration and assistance. |
>
> _______________________________________________
> varnish-misc mailing list
> varnish-misc@varnish-cache.org<mailto:varnish-misc@varnish-cache.org>
> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>
>
Re: Backend Fetch failed [ In reply to ]
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

For problems like this, *always look for the FetchError entry in the
backend logs*.

> << BeReq >> 65547
[...]
> - FetchError no backend connection - Timestamp Beresp:
> 1491485655.912871 0.000051 0.000051 - Timestamp Error:
> 1491485655.912878 0.000059 0.000007
[...]
> - End

The client-side logs, on the other hand, frankly don't matter -- not
for the purposes of diagnosing the problem with the backend fetch. So
I'll just ignore them altogether.

> * << Request >> 65546
[...]
> - End

> * << Request >> 5
[...]
> - End

> * << BeReq >> 6
[...]
> - FetchError no backend connection - Timestamp Beresp:
> 1491485659.606340 0.000056 0.000056 - Timestamp Error:
> 1491485659.606347 0.000062 0.000006
[...]

FetchError "no backend connection" very likely means, in this case,
that your backend is failing its health checks, so that Varnish
determines that there is no healthy backend to which it can direct the
requests.

There is one other possibility for "no backend connection", which is
that Varnish attempted to initiate a network connection to the
backend, but the connection could not be obtained before
connect_timeout expired. In that case, the timestamps would have shown
that almost exactly as much time as connect_timeout would have been
taken, which for your config would be very obvious (more about that
further down). But as you see here in the Timestamp entries, Varnish
determined the error after about 50 microseconds, which is
near-certain proof that the health checks failed (about enough time
for Varnish to check its record that the backend is unhealthy).

You can see the results of the health checks in the log, but for that
you need raw grouping, since health checks are not transactional (they
are not part of requests/responses that Varnish serves):

$ varnishlog -g raw -i Backend_health

Your health checks are probably failing because you've written the
probes incorrectly:

backend drupal {
[...]
.probe = {
.url = "drupal.miat.com<http://drupal.miat.com>";
[...]
}
}

This is very common misunderstanding: "url" in the conceptual world of
Varnish only ever refers to the *path*; the domain should not appear
there. So your probes should say something like:

backend drupal {
[...]
.probe = {
.url = "/"; # or whatever path should be used for probes
[...]
}
}

Even after you fix that, you're really taking chances with the short
timeout for the probes:

.probe = {
[...]
.timeout = 60ms;
[...]
}

Are you sure that your backends will always respond to the health
probes within 60 milliseconds? Set it to 1s and give them a chance.

That, I think, is the cause of your 503 problem, but I have to say
something about this as well, the timeouts you have set for all of
your backends:

.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;

Those timeouts are astonishingly, appallingly, gobsmackingly too long.
Just looking at that is almost making my head explode.

This is another common mistake: setting the Varnish timeouts to
"forever and ever and ever". On the contrary, you're much better off
if the timeouts are set to *fail fast*.

Setting your timeouts to 100 minutes helps absolutely no one at all --
it means that a worker thread in Varnish will sit idle for 100
minutes, waiting for something to happen. Worker threads are a limited
resource in Varnish; you want them to keep doing useful work, and give
up relatively soon if a backend is not responding. If there is a
serious problem in your system, so that many backends are not
responding, then your worker threads will all go idle waiting for the
timeouts to expire, and Varnish will have to start new threads.
Eventually the maximum number of threads will be reached, and when
that happens, Varnish will start to refuse new requests, which usually
means that your site goes down altogether. It's a recipe for disaster.

Rest assured that if your backend has not responded for 5999 seconds,
then it's not going to respond in the 6000th second either. It's not
responding at all.

Consider just going with the default timeouts, or with something on
the order of 6 seconds, rather than 6000 seconds. Or maybe 60 seconds,
but that's already getting too long. If your backend developers can't
get their apps to respond within a few seconds, then go yell at them
until they do. As the Varnish admin, you *cannot* solve that problem
for them, by setting your timeouts to "until the end of time".


HTH,
Geoff
- --
** * * UPLEX - Nils Goroll Systemoptimierung

Scheffelstra?e 32
22301 Hamburg

Tel +49 40 2880 5731
Mob +49 176 636 90917
Fax +49 40 42949753

http://uplex.de

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_______________________________________________
varnish-misc mailing list
varnish-misc@varnish-cache.org
https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
RE: Backend Fetch failed [ In reply to ]
I will definitely make those changes appreciate your help. I make that change under the .probe and the site started working "/";

-----Original Message-----
From: Geoff Simmons [mailto:geoff@uplex.de]
Sent: Thursday, April 06, 2017 1:38 PM
To: Rodney Bizzell <rbizzell@measinc.com>
Cc: varnish-misc@varnish-cache.org
Subject: Re: Backend Fetch failed

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

For problems like this, *always look for the FetchError entry in the backend logs*.

> << BeReq >> 65547
[...]
> - FetchError no backend connection - Timestamp Beresp:
> 1491485655.912871 0.000051 0.000051 - Timestamp Error:
> 1491485655.912878 0.000059 0.000007
[...]
> - End

The client-side logs, on the other hand, frankly don't matter -- not for the purposes of diagnosing the problem with the backend fetch. So I'll just ignore them altogether.

> * << Request >> 65546
[...]
> - End

> * << Request >> 5
[...]
> - End

> * << BeReq >> 6
[...]
> - FetchError no backend connection - Timestamp Beresp:
> 1491485659.606340 0.000056 0.000056 - Timestamp Error:
> 1491485659.606347 0.000062 0.000006
[...]

FetchError "no backend connection" very likely means, in this case, that your backend is failing its health checks, so that Varnish determines that there is no healthy backend to which it can direct the requests.

There is one other possibility for "no backend connection", which is that Varnish attempted to initiate a network connection to the backend, but the connection could not be obtained before connect_timeout expired. In that case, the timestamps would have shown that almost exactly as much time as connect_timeout would have been taken, which for your config would be very obvious (more about that further down). But as you see here in the Timestamp entries, Varnish determined the error after about 50 microseconds, which is near-certain proof that the health checks failed (about enough time for Varnish to check its record that the backend is unhealthy).

You can see the results of the health checks in the log, but for that you need raw grouping, since health checks are not transactional (they are not part of requests/responses that Varnish serves):

$ varnishlog -g raw -i Backend_health

Your health checks are probably failing because you've written the probes incorrectly:

backend drupal {
[...]
.probe = {
.url = "drupal.miat.com<http://drupal.miat.com>";
[...]
}
}

This is very common misunderstanding: "url" in the conceptual world of Varnish only ever refers to the *path*; the domain should not appear there. So your probes should say something like:

backend drupal {
[...]
.probe = {
.url = "/"; # or whatever path should be used for probes [...]
}
}

Even after you fix that, you're really taking chances with the short timeout for the probes:

.probe = {
[...]
.timeout = 60ms;
[...]
}

Are you sure that your backends will always respond to the health probes within 60 milliseconds? Set it to 1s and give them a chance.

That, I think, is the cause of your 503 problem, but I have to say something about this as well, the timeouts you have set for all of your backends:

.connect_timeout = 6000s;
.first_byte_timeout = 6000s;
.between_bytes_timeout = 6000s;

Those timeouts are astonishingly, appallingly, gobsmackingly too long.
Just looking at that is almost making my head explode.

This is another common mistake: setting the Varnish timeouts to "forever and ever and ever". On the contrary, you're much better off if the timeouts are set to *fail fast*.

Setting your timeouts to 100 minutes helps absolutely no one at all -- it means that a worker thread in Varnish will sit idle for 100 minutes, waiting for something to happen. Worker threads are a limited resource in Varnish; you want them to keep doing useful work, and give up relatively soon if a backend is not responding. If there is a serious problem in your system, so that many backends are not responding, then your worker threads will all go idle waiting for the timeouts to expire, and Varnish will have to start new threads.
Eventually the maximum number of threads will be reached, and when that happens, Varnish will start to refuse new requests, which usually means that your site goes down altogether. It's a recipe for disaster.

Rest assured that if your backend has not responded for 5999 seconds, then it's not going to respond in the 6000th second either. It's not responding at all.

Consider just going with the default timeouts, or with something on the order of 6 seconds, rather than 6000 seconds. Or maybe 60 seconds, but that's already getting too long. If your backend developers can't get their apps to respond within a few seconds, then go yell at them until they do. As the Varnish admin, you *cannot* solve that problem for them, by setting your timeouts to "until the end of time".


HTH,
Geoff
- --
** * * UPLEX - Nils Goroll Systemoptimierung

Scheffelstra?e 32
22301 Hamburg

Tel +49 40 2880 5731
Mob +49 176 636 90917
Fax +49 40 42949753

http://uplex.de

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