VCL file

gistfile1.txt

backend static1 {
    .host = "10.1.1.85";
    .port = "81";
    .probe = {
        .request =
            "GET /robots.txt?healthcheck=varnish&monitor=Monitor_s.pixfs.net HTTP/1.1"
            "Host: s.pixfs.net"
            "Connection: close";
        .interval = 5 s;
        .timeout = 2 s;
        .window = 1;
        .threshold = 1;
    }
}

backend static2 {
    .host = "10.1.1.219";
    .port = "81";
    .probe = {
        .request =
            "GET /robots.txt?healthcheck=varnish&monitor=Monitor_s.pixfs.net HTTP/1.1"
            "Host: s.pixfs.net"
            "Connection: close";
        .interval = 5 s;
        .timeout = 2 s;
        .window = 1;
        .threshold = 1;
    }
}

backend static3 {
    .host = "10.1.1.215";
    .port = "81";
    .probe = {
        .request =
            "GET /robots.txt?healthcheck=varnish&monitor=Monitor_s.pixfs.net HTTP/1.1"
            "Host: s.pixfs.net"
            "Connection: close";
        .interval = 5 s;
        .timeout = 2 s;
        .window = 1;
        .threshold = 1;
    }
}

director static round-robin {
        { .backend = static1; }
        { .backend = static2; }
        { .backend = static3; }
}

acl purge {
        "localhost";
        "10.0.0.0"/8;
}

sub vcl_recv {
        if (req.http.host ~ "^s.pixfs.net$" || req.http.host ~ "^css.pixnet.in$" || req.http.host ~ "^s.pimg.tw$") {
                set req.backend = static;
        }

        if (req.request == "GET") {
                return(lookup);
        }

        if (req.request == "PURGE") {
                if (!client.ip ~ purge) {
                        error 403 "Forbidden";
                }
                return(lookup);
        }

        return(lookup);
}

sub vcl_hit {
        if (req.request == "PURGE") {
                set obj.ttl = 0s;
                error 200 "Purged";
        }

        return(deliver);
}

sub vcl_miss {
        if (req.request == "PURGE") {
                error 404 "Not Found";
        }
}

sub vcl_fetch {
        # max_restarts defaults to 4.
        if (beresp.status != 200 && beresp.status != 204
                        && beresp.status != 403 && beresp.status != 404
                        && beresp.status != 301 && beresp.status != 302) {
                return(restart);
        }

        if (beresp.status >= 400) {
                set beresp.ttl = 0s;
        }

        if (req.request == "HEAD") {
                set beresp.http.head = "yes";
        }

        set beresp.http.X-Cacheable = "YES";        
        if (req.url ~ "\.(css|js|html|htm|xml|txt)$") {
                set beresp.do_gzip = true;
        }
        return(deliver);
}

sub vcl_deliver {
        set resp.http.X-Served-By = server.hostname;
        if (obj.hits > 0) {
                set resp.http.X-Cache = "HIT";
                set resp.http.X-Cache-Hits = obj.hits;
        } else {
                set resp.http.X-Cache = "MISS";
        }

        return(deliver);
}