Magento 2 – Varnish Cache Not Clearing from Admin

• M2 Version : 2.2.2

• PHP : version : 7.1.26

• Varnish version : 6.0.2

• Server : Nginx

• I have configure varnish in my magento website it working well i have checked in frontend and and passed all test as describe in
  doc.
• I have setup How Magento cache clearing works with Varnish. but not working let me share my configuration

env.php

<?php
return array (
  'backend' => 
  array (
    'frontName' => 'admin',
  ),
  'crypt' => 
  array (
    'key' => '226p485aa12738648ac1865cadf6304a
2065c6db0ef584f4804ba9fd703cd112',
  ),
  'db' => 
  array (
    'table_prefix' => '',
    'connection' => 
    array (
      'default' => 
      array (
        'host' => 'localhost',
        'dbname' => 'test',
        'username' => 'test',
        'password' => 'pass',
        'active' => '1',
        'model' => 'mysql4',
        'engine' => 'innodb',
        'initStatements' => 'SET NAMES utf8;',
      ),
    ),
  ),
  'resource' => 
  array (
    'default_setup' => 
    array (
      'connection' => 'default',
    ),
  ),
  'x-frame-options' => 'SAMEORIGIN',
  'MAGE_MODE' => 'developer',
  'session' => 
  array (
    'save' => 'redis',
    'redis' => 
    array (
      'host' => '127.0.0.1',
      'port' => '6379',
      'password' => '',
      'timeout' => '2.5',
      'persistent_identifier' => '',
      'database' => '2',
      'compression_threshold' => '2048',
      'compression_library' => 'gzip',
      'log_level' => '3',
      'max_concurrency' => '6',
      'break_after_frontend' => '5',
      'break_after_adminhtml' => '30',
      'first_lifetime' => '600',
      'bot_first_lifetime' => '60',
      'bot_lifetime' => '7200',
      'disable_locking' => '0',
      'min_lifetime' => '60',
      'max_lifetime' => '2592000',
    ),
  ),
  'cache_types' => 
  array (
    'config' => 1,
    'layout' => 1,
    'block_html' => 1,
    'collections' => 1,
    'reflection' => 1,
    'db_ddl' => 1,
    'eav' => 1,
    'customer_notification' => 1,
    'config_integration' => 1,
    'config_integration_api' => 1,
    'full_page' => 1,
    'translate' => 1,
    'config_webservice' => 1,
    'compiled_config' => 1,
    'cart2quote_license' => 0,
  ),
  'install' => 
  array (
    'date' => 'Tue, 06 Feb 2018 05:18:03 +0000',
  ),
  'system' => 
  array (
    'default' => 
    array (
      'dev' => 
      array (
        'debug' => 
        array (
          'debug_logging' => '0',
        ),
      ),
    ),
  ),
  'cache' => 
  array (
    'frontend' => 
    array (
      'default' => 
      array (
        'backend' => 'Cm_Cache_Backend_Redis',
        'backend_options' => 
        array (
          'server' => '127.0.0.1',
          'port' => '6379',
          'persistent' => '',
          'database' => '0',
          'password' => '',
          'force_standalone' => '0',
          'connect_retries' => '1',
          'read_timeout' => '10',
          'automatic_cleaning_factor' => '0',
          'compress_data' => '1',
          'compress_tags' => '1',
          'compress_threshold' => '20480',
          'compression_lib' => 'gzip',
          'use_lua' => '0',
        ),
      ),
      'page_cache' => 
      array (
        'backend' => 'Cm_Cache_Backend_Redis',
        'backend_options' => 
        array (
          'server' => '127.0.0.1',
          'port' => '6379',
          'persistent' => '',
          'database' => '1',
          'password' => '',
          'force_standalone' => '0',
          'connect_retries' => '1',
          'lifetimelimit' => '57600',
          'compress_data' => '0',
        ),
      ),
    ),
  ),
  'http_cache_hosts' => 
  array (
    0 => 
    array (
      'host' => '127.0.0.1',
      'port' => '8080',
    ),
  ),
);

varnish.vcl

# VCL version 5.0 is not supported so it should be 4.0 even though actually used Varnish version is 5
vcl 4.0;

import std;
# The minimal Varnish version is 5.0
# For SSL offloading, pass the following header in your proxy server or load balancer: 'X-Forwarded-Proto: https'

backend default {
    .host = "127.0.0.1";
    .port = "8080";
    .first_byte_timeout = 600s;
    .probe = {
        .url = "/health_check.php";
        .timeout = 2s;
        .interval = 5s;
        .window = 10;
        .threshold = 5;
   }
}

acl purge {
    "localhost";
}

sub vcl_recv {
    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);
        }
        if (req.http.X-Pool) {
          ban("obj.http.X-Pool ~ " + req.http.X-Pool);
        }
        return (synth(200, "Purged"));
    }

    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 ~ "/pub/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 {
            # unkown algorithm
            unset req.http.Accept-Encoding;
        }
    }

    # Remove Google gclid parameters to minimize the cache objects
    set req.url = regsuball(req.url,"\?gclid=[^&]+$",""); # strips when QS = "?gclid=AAA"
    set req.url = regsuball(req.url,"\?gclid=[^&]+&","?"); # strips when QS = "?gclid=AAA&foo=bar"
    set req.url = regsuball(req.url,"&gclid=[^&]+",""); # strips when QS = "?foo=bar&gclid=AAA" or QS = "?foo=bar&gclid=AAA&bar=baz"

    # 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);
    }

}

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
    # images, css and js are cacheable by default so we have to remove cookie also
    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;
    }

    # 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_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 (miss);
        }
    } else {
        # server is not healthy, retrieve from cache
        set req.http.grace = "unlimited (unhealthy server)";
        return (deliver);
    }
}