We have a magento 2.4.0 store. Most of our products are configurable. And some of them are having a lot of options. We also use swatch options.
We have discovered some links which return:
Error 503 Backend fetch failed
Backend fetch failed
Guru Meditation:
XID: 56884378
Varnish cache server
My Nginx configuration file:
autoindex off;
sendfile on;
tcp_nodelay on;
keepalive_timeout 25;
client_body_timeout 15;
client_header_timeout 15;
send_timeout 15;
types_hash_max_size 2048;
server_tokens off;
client_max_body_size 64M;
client_body_buffer_size 128k;
client_header_buffer_size 16k;
large_client_header_buffers 4 16k;
fastcgi_read_timeout 300;
proxy_read_timeout 300;
fastcgi_buffer_size 256k;
fastcgi_buffers 16 256k;
open_file_cache max=50000 inactive=30s;
open_file_cache_valid 30s;
open_file_cache_min_uses 2;
gzip on;
gzip_vary on;
gzip_disable "MSIE [1-6].";
gzip_static on;
gzip_min_length 1400;
gzip_buffers 16 8k;
gzip_http_version 1.1;
gzip_comp_level 6;
gzip_proxied any;
gzip_types text/plain text/css text/xml application/javascript application/x-javascript application/xml application/xml+rss application/ecmascript application/json image/svg+xml ;
My vhost file:
fastcgi_index index.php;
fastcgi_pass golfcoukbackend;
fastcgi_buffers 16 256k;
fastcgi_buffer_size 256k;
fastcgi_read_timeout 600s;
fastcgi_connect_timeout 600s;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
location ~* .(ico|jpg|jpeg|png|gif|svg|js|css|swf|eot|ttf|otf|woff|woff2)$ {
add_header Cache-Control "public";
add_header X-Frame-Options "SAMEORIGIN";
expires +1y;
}
}
Nginx seems that does not have issue.
Varnish default.vcl file:
# Varnish configuration
vcl 4.0;
import std;
# The minimal Varnish version is 6.0
# For SSL offloading, pass the following header in your proxy server or load balancer: 'X-Forwarded-Proto: https'
backend default {
.host = "10.2.37.9";
.port = "8080";
.first_byte_timeout = 600s;
# .probe = {
# .url = "/health_check.php";
# .timeout = 2s;
# .interval = 5s;
# .window = 10;
# .threshold = 5;
# }
}
acl purge {
"127.0.0.1";
"myip";
"10.2.37.9";
}
sub vcl_recv {
# For multiple backends, uncomment the below. Ensure you are using the right
# selection code depending on the type of loadbalancing being used.
# set req.backend_hint = prod_web.backend();
# Remove this if using multiple backends.
set req.backend_hint = default;
# To Exclude a Domain uncomment the below
#if (req.http.host ~ "exampledomain.com") {
#return (pass);
#}
if (req.restarts > 0) {
set req.hash_always_miss = true;
}
# Exclude domain example
if (req.http.host ~ "exampledomain.com") {
return (pass);
}
# Exclude URI example
if (req.url ~ "^/.well-known/") {
return (pass);
}
if (req.method == "PURGE") {
if (client.ip !~ purge) {
return (synth(405, "Method not allowed"));
}
# To use the X-Pool header for purging varnish during automated deployments, make sure the X-Pool header
# has been added to the response in your backend server config. This is used, for example, by the
# capistrano-magento2 gem for purging old content from varnish during it's deploy routine.
if (!req.http.X-Magento-Tags-Pattern && !req.http.X-Pool) {
return (synth(400, "X-Magento-Tags-Pattern or X-Pool header required"));
}
if (req.http.X-Magento-Tags-Pattern) {
ban("obj.http.X-Magento-Tags ~ " + req.http.X-Magento-Tags-Pattern);
}
# ban everything to catch assets as well
if (req.http.X-Magento-Tags-Pattern == ".*") {
ban("req.url ~ .*");
}
if (req.http.X-Pool) {
ban("obj.http.X-Pool ~ " + req.http.X-Pool);
}
return (synth(200, "Purged"));
}
# HTTP -> HTTPS
if (req.http.X-Forwarded-Proto !~ "https") {
set req.http.location = "https://" + req.http.host + req.url;
return (synth(750, "Permanently moved"));
}
if (req.method != "GET" &&
req.method != "HEAD" &&
req.method != "PUT" &&
req.method != "POST" &&
req.method != "TRACE" &&
req.method != "OPTIONS" &&
req.method != "DELETE") {
/* Non-RFC2616 or CONNECT which is weird. */
return (pipe);
}
# We only deal with GET and HEAD by default
if (req.method != "GET" && req.method != "HEAD") {
return (pass);
}
# Bypass shopping cart, checkout and search requests
if (req.url ~ "/checkout" || req.url ~ "/catalogsearch") {
return (pass);
}
# Bypass health check requests
if (req.url ~ "/health_check.php") {
return (pass);
}
# Set initial grace period usage status
set req.http.grace = "none";
# normalize url in case of leading HTTP scheme and domain
set req.url = regsub(req.url, "^http[s]?://", "");
# collect all cookies
std.collect(req.http.Cookie);
# Compression filter. See https://www.varnish-cache.org/trac/wiki/FAQ/Compression
if (req.http.Accept-Encoding) {
if (req.url ~ ".(jpg|jpeg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|swf|flv)$") {
# No point in compressing these
unset req.http.Accept-Encoding;
} elsif (req.http.Accept-Encoding ~ "gzip") {
set req.http.Accept-Encoding = "gzip";
} elsif (req.http.Accept-Encoding ~ "deflate" && req.http.user-agent !~ "MSIE") {
set req.http.Accept-Encoding = "deflate";
} else {
# unknown algorithm
unset req.http.Accept-Encoding;
}
}
# Remove all marketing get parameters to minimize the cache objects
if (req.url ~ "(?|&)(gclid|cx|ie|cof|siteurl|zanpid|origin|fbclid|mc_[a-z]+|utm_[a-z]+|_bta_[a-z]+)=") {
set req.url = regsuball(req.url, "(gclid|cx|ie|cof|siteurl|zanpid|origin|fbclid|mc_[a-z]+|utm_[a-z]+|_bta_[a-z]+)=[-_A-z0-9+()%.]+&?", "");
set req.url = regsub(req.url, "[?|&]+$", "");
}
# Static files caching
if (req.url ~ "^/(pub/)?(media|static)/") {
# Static files should not be cached by default
return (pass);
# But if you use a few locales and don't use CDN you can enable caching static files by commenting previous line (#return (pass);) and uncommenting next 3 lines
#unset req.http.Https;
#unset req.http.X-Forwarded-Proto;
#unset req.http.Cookie;
}
return (hash);
}
sub vcl_hash {
if (req.http.cookie ~ "X-Magento-Vary=") {
hash_data(regsub(req.http.cookie, "^.*?X-Magento-Vary=([^;]+);*.*$", "1"));
}
# For multi site configurations to not cache each other's content
if (req.http.host) {
hash_data(req.http.host);
} else {
hash_data(server.ip);
}
# To make sure http users don't see ssl warning
if (req.http.X-Forwarded-Proto) {
hash_data(req.http.X-Forwarded-Proto);
}
if (req.url ~ "/graphql") {
call process_graphql_headers;
}
}
sub process_graphql_headers {
if (req.http.Store) {
hash_data(req.http.Store);
}
if (req.http.Content-Currency) {
hash_data(req.http.Content-Currency);
}
}
sub vcl_backend_response {
set beresp.grace = 3d;
if (beresp.http.content-type ~ "text") {
set beresp.do_esi = true;
}
if (bereq.url ~ ".js$" || beresp.http.content-type ~ "text") {
set beresp.do_gzip = true;
}
if (beresp.http.X-Magento-Debug) {
set beresp.http.X-Magento-Cache-Control = beresp.http.Cache-Control;
}
# cache only successfully responses and 404s
if (beresp.status != 200 && beresp.status != 404) {
set beresp.ttl = 0s;
set beresp.uncacheable = true;
return (deliver);
} elsif (beresp.http.Cache-Control ~ "private") {
set beresp.uncacheable = true;
set beresp.ttl = 86400s;
return (deliver);
}
# validate if we need to cache it and prevent from setting cookie
if (beresp.ttl > 0s && (bereq.method == "GET" || bereq.method == "HEAD")) {
unset beresp.http.set-cookie;
}
# If page is not cacheable then bypass varnish for 2 minutes as Hit-For-Pass
if (beresp.ttl <= 0s ||
beresp.http.Surrogate-control ~ "no-store" ||
(!beresp.http.Surrogate-Control &&
beresp.http.Cache-Control ~ "no-cache|no-store") ||
beresp.http.Vary == "*") {
# Mark as Hit-For-Pass for the next 2 minutes
set beresp.ttl = 120s;
set beresp.uncacheable = true;
}
return (deliver);
}
sub vcl_deliver {
if (resp.http.X-Magento-Debug) {
if (resp.http.x-varnish ~ " ") {
set resp.http.X-Magento-Cache-Debug = "HIT";
set resp.http.Grace = req.http.grace;
} else {
set resp.http.X-Magento-Cache-Debug = "MISS";
}
} else {
unset resp.http.Age;
}
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";
}
# Not letting browser to cache non-static files.
if (resp.http.Cache-Control !~ "private" && req.url !~ "^/(pub/)?(media|static)/") {
set resp.http.Pragma = "no-cache";
set resp.http.Expires = "-1";
set resp.http.Cache-Control = "no-store, no-cache, must-revalidate, max-age=0";
}
unset resp.http.X-Magento-Debug;
unset resp.http.X-Magento-Tags;
unset resp.http.X-Powered-By;
unset resp.http.Server;
unset resp.http.X-Varnish;
unset resp.http.Via;
unset resp.http.Link;
}
sub vcl_synth {
if (resp.status == 750) {
set resp.http.location = req.http.location;
set resp.status = 301;
return (deliver);
}
}
#sub vcl_hit {
# if (obj.ttl >= 0s) {
# Hit within TTL period
# return (deliver);
# }
# if (std.healthy(req.backend_hint)) {
# if (obj.ttl + 300s > 0s) {
# Hit after TTL expiration, but within grace period
# set req.http.grace = "normal (healthy server)";
# return (deliver);
# } else {
# Hit after TTL and grace expiration
# return (restart);
# }
# } else {
# server is not healthy, retrieve from cache
# set req.http.grace = "unlimited (unhealthy server)";
# return (deliver);
# }
#}
Varnish runs with default hdr_len
If I am right our issue is related with magento 2 bug with configurable products and big headers which are coming when there is a configurable products with a lot of variations.
https://github.com/magento/magento2/issues/23834
I have tried a solution described in above link which disable plugin product_identities_extender. This fixes the problem but not in all our products…
Some still return Backend fetch failed
Any help please? I am in dead end here!
