varnish throwing 503 error after separating it into container

Question

Below are the Varnish container and its log and application container and its log.

before i separate varnish into container the varnish was working fine within application container with the same below setup, but varnish throws 503/500 error after i separate into a container

the below log, i see when i try to update the content on application. Varnish container IP : 172.100.0.10 exposed port 8443, Application container IP: 172.100.0.2

Varnish Container Log

/etc/varnish # varnishlog
-   RespProtocol   HTTP/1.1
-   RespStatus     503
-   RespReason     Service Unavailable

Application Container Log

[root@application-container www]# tail -f /var/log/httpd/ssl_request_log
[21/Apr/2023:06:26:51 +0200] 172.100.0.1 TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256 "PUT /application/shared-content/59b2a2390d3b922876493013?_dc=1682051211645 HTTP/1.1" 275

default.vcl

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

import std;

# Default backend definition. Set this to point to your content server.
backend default {
  .host = "application-container";
  .port = "8080";
}

backend blogproxy {
  .host = "ip";
  .port = "80";
}

acl abc {
    "application-container";
}

acl abc_loadbalancer {
    "application-container";
}

sub vcl_recv {
    # Use true client ip from Akamai CDN
    if (req.http.True-Client-IP) {
       set req.http.X-Forwarded-For = req.http.True-Client-IP;
    }

    if (req.restarts == 0) {
       if (req.http.X-Forwarded-For && client.ip !~ abc_loadbalancer) {
           set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip;
       } elseif (client.ip !~ abc_loadbalancer) {
           set req.http.X-Forwarded-For = client.ip;
       }
    }

    if(req.method == "BAN") {
        if (client.ip !~ abc) {
            return(synth(405, "Not allowed"));
        }

        ban("obj.http.x-url == " + req.url);

        return(synth(200, "Ban added"));
    }

    if (req.http.host ~ "^nl-s_app" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.s_app.nl";
        set req.http.X-Forwarded-Host = "www.s_app.nl";

        return(pass);
    }

    if (req.http.host ~ "^www\.s_app\.de" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.s_app.nl";
        set req.http.X-Forwarded-Host = "www.s_app.de";

        return(pass);
    }

    if (req.http.host ~ "^www\.s_app\.fr" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.s_app.nl";
        set req.http.X-Forwarded-Host = "www.s_app.fr";

        return(pass);
    }

    if (req.http.host ~ "^www\.s_app\.co\.uk" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.s_app.nl";
        set req.http.X-Forwarded-Host = "www.s_app.co.uk";

        return(pass);
    }

    if (req.http.host ~ "^nl-application" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.application.nl";
        set req.http.X-Forwarded-Host = "www.application.nl";

        return(pass);
    }

    if (req.http.host ~ "^de-application" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.application.nl";
        set req.http.X-Forwarded-Host = "www.application.de";

        return(pass);
    }

    if (req.http.host ~ "^fr-application" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.application.nl";
        set req.http.X-Forwarded-Host = "www.application.fr";

        return(pass);
    }

    if (req.http.host ~ "^en-application" && req.url ~ "^/blog/") {
        set req.backend_hint = blogproxy;
        set req.http.host = "blogproxy.application.nl";
        set req.http.X-Forwarded-Host = "www.application.co.uk";

        return(pass);
    }

    if (req.http.url ~ "^/xml.*") {
        return (pass);
    }

    if (req.http.host ~ "^api") {
        return (pipe);
    }

    # Only bypass cache for development
    if (req.http.Cache-Control ~ "(private|no-cache|no-store)" || req.http.Pragma == "no-cache") {
        return (pipe);
    }

    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 (pass);
    }

    # Never cache POST or HEAD requests
    if (
        req.method == "HEAD" ||
        req.method == "POST" ||
        req.method == "PUT") {
        return (pass);
    }

    # Set a header announcing Surrogate Capability to the origin
    if (req.http.Surrogate-Control ~ "content\x3D\x22ESI\/1\.0\x22\x3BAkamai") {
        set req.http.Surrogate-Capability = "akamai=ESI/1.0";
    } else {
        set req.http.Surrogate-Capability = "varnish=ESI/1.0";
    }

    # Skip Varnish for the CMS
    if (req.http.host ~ "^cms-application") {
        return (pass);
    }

    # Sync jobs should also not use Varnish
    if (req.url ~ "sync") {
        return (pass);
    }

    if (req.url ~ "logout" || req.url ~ "callback" || req.url ~ "account" || req.url ~ "/affiliate/") {
        return (pass);
    }

    # Normalize the accept encoding header
    call normalize_accept_encoding;

    # Strip cookies from static assets
    if (req.url ~ "(?i)\.(css|js|txt|xml|bmp|png|gif|jpeg|jpg|svg|ico|mp3|mp4|swf|flv|ttf|woff|pdf)(\?.*)?$") {
        unset req.http.Cookie;
    }

    # Serving ESI
    if (req.esi_level > 0) {
        set req.http.X-Esi = 1;
        set req.http.X-Esi-Parent = req_top.url;
    } else {
        unset req.http.X-Esi;
    }

    # Strip not allowed cookies
    call strip_not_allowed_cookies;

    # Strip out all Google query parameters
    call strip_google_query_params;

    # Strip hash, server doesn't need it.
    if (req.url ~ "\#") {
        set req.url = regsub(req.url, "\#.*$", "");
    }

    # if (req.http.X-Forwarded-For ~ "80.95.169.59") {
    # if (client.ip ~ abc) {
        # Enable the feature toggle button via cookie
        # set req.http.Cookie = "abcToggle-abc-feature-toggles=true;" + req.http.Cookie;
    # }

    return (hash);
}

sub vcl_backend_response {
    set beresp.http.x-url = bereq.url;
    set beresp.http.x-host = bereq.http.host;

    if (beresp.status == 500 || beresp.status == 502 || beresp.status == 503 || beresp.status == 504) {
        return (abandon);
    }

        # Stop Caching 302 or 301 or 303 redirects
    if (beresp.status == 302 || beresp.status == 301 || beresp.status == 303) {
       set beresp.ttl = 0s;
       set beresp.uncacheable = true;
       return (deliver);
    }

    # Don't cache 404 responses
    if ( beresp.status == 404 ) {
        set beresp.ttl = 0s;
        set beresp.uncacheable = true;
        return (deliver);
    }

    # Set cache-control headers for 410
    if (beresp.status == 410) {
        set beresp.ttl = 2d;
    }

    if (bereq.http.Surrogate-Control ~ "content\x3D\x22ESI\/1\.0\x22\x3BAkamai") {
        set beresp.do_esi = false;
        set beresp.http.X-Esi-Processor = bereq.http.Surrogate-Control;
    } elseif (beresp.http.Surrogate-Control ~ "ESI/1.0") {
        unset beresp.http.Surrogate-Control;
        set beresp.do_esi = true;
        set beresp.http.X-Esi-Processor = bereq.http.Surrogate-Control;
    }

    unset beresp.http.Vary;

    # Strip cookies from static assets
    if (bereq.url ~ "\.(css|js|txt|xml|bmp|png|gif|jpeg|jpg|svg|ico|mp3|mp4|swf|flv|ttf|woff|pdf)$") {
        unset beresp.http.Set-cookie;
    }

    # Mark as "Hit-For-Pass" for the next 5 minutes
    # Zend-Auth (EC session handling) cookie isset, causing no page to be cached anymore.
    # if (beresp.ttl <= 0s || beresp.http.Set-Cookie || beresp.http.Vary == "*") {
    if (beresp.ttl <= 0s || beresp.http.Vary == "*") {
        set beresp.uncacheable = true;
        set beresp.ttl = 300s;
    }

    # Grace: when several clients are requesting the same page Varnish will send one request to the webserver and
    # serve old cache to the others for x secs
    set beresp.grace = 30s;

    return (deliver);
}

sub vcl_deliver {
    # Add a header indicating the response came from Varnish, only for ABC IP addresses
    # if (std.ip(regsub(req.http.X-Forwarded-For, "[, ].*$", ""), "0.0.0.0") ~ abc) {
        set resp.http.X-Varnish-Client-IP = client.ip;
        set resp.http.X-Varnish-Server-IP = server.ip;
        set resp.http.X-Varnish-Local-IP = local.ip;
        set resp.http.X-Varnish-Remote-IP = remote.ip;
        set resp.http.X-Varnish-Forwarded-For = req.http.X-Forwarded-For;
        set resp.http.X-Varnish-Webserver = "abc-cache-dev";
        set resp.http.X-Varnish-Cache-Control = resp.http.Cache-Control;
        set resp.http.X-Edge-Control = resp.http.Edge-Control;

        if (resp.http.x-varnish ~ " ") {
            set resp.http.X-Varnish-Cache = "HIT";
            set resp.http.X-Varnish-Cached-Hits = obj.hits;
        } else {
            set resp.http.X-Varnish-Cached = "MISS";
        }


        # Add a header indicating the feature toggle status
        set resp.http.X-Varnish-FeatureToggle = req.http.FeatureToggle;
    #} else {
    #    unset resp.http.x-varnish-tags;
    #}

    # strip host and url headers, no need to send it to the client
    unset resp.http.x-url;
    unset resp.http.x-host;

    return (deliver);
}

# strip host and url headers, no need to send it to the client
sub strip_not_allowed_cookies {
    if (req.http.Cookie) {
        set req.http.Cookie = ";" + req.http.Cookie;
        set req.http.Cookie = regsuball(req.http.Cookie, "; +", ";");
        set req.http.Cookie = regsuball(req.http.Cookie, ";(abcToggle-[^;]*)=", "; \1=");
        # set req.http.Cookie = regsuball(req.http.Cookie, ";(redirect_url)=", "; \1=");
        set req.http.Cookie = regsuball(req.http.Cookie, ";[^ ][^;]*", "");
        set req.http.Cookie = regsuball(req.http.Cookie, "^[; ]+|[; ]+$", "");

        if (req.http.Cookie == "") {
            unset req.http.Cookie;
        }
    }
}

# Remove the Google Analytics added parameters, useless for our backend
sub strip_google_query_params {
    if (req.url ~ "(\?|&)(utm_source|utm_medium|utm_campaign|gclid|cx|ie|cof|siteurl|_ga|PHPSESSID)=" && req.url !~ "(tradedoubler|index\.html|deeplink|affiliate)" && req.url !~ "^\/[0-9]{6}") {
        set req.url = regsuball(req.url, "&(utm_source|utm_medium|utm_campaign|gclid|cx|ie|cof|siteurl|_ga|PHPSESSID)=([A-z0-9_\-\.%25]+)", "");
        set req.url = regsuball(req.url, "\?(utm_source|utm_medium|utm_campaign|gclid|cx|ie|cof|siteurl|_ga|PHPSESSID)=([A-z0-9_\-\.%25]+)", "?");
        set req.url = regsub(req.url, "\?&", "?");
        set req.url = regsub(req.url, "\?$", "");
    }
}

# Normalize the accept-encoding header to minimize the number of cache variations
sub normalize_accept_encoding {
    if (req.http.Accept-Encoding) {
        if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg)$") {
            # Skip, files are already compressed
            unset req.http.Accept-Encoding;
        } elseif (req.http.Accept-Encoding ~ "gzip") {
            set req.http.Accept-Encoding = "gzip";
        } elsif (req.http.Accept-Encoding ~ "deflate") {
            set req.http.Accept-Encoding = "deflate";
        } else {
            # unknown algorithm
            unset req.http.Accept-Encoding;
        }
    }
}

sub vcl_hash {
    # Add the feature toggles to the hash
    if (req.http.Cookie ~ "abcToggle-") {
        set req.http.FeatureToggle = regsuball(req.http.cookie, "(abcToggle-[^;]*)", "\1");
        hash_data(req.http.FeatureToggle);
    }

    if (req.http.X-Akamai-Staging ~ "ESSL") {
        hash_data(req.http.x-akamai-staging);
    }

    # When the ESI handling is not done by Akamai, create a new cache set, because varnish will process the ESI tags.
    if (req.http.Surrogate-Control !~ "content\x3D\x22ESI\/1\.0\x22\x3BAkamai") {
        hash_data("varnish-handles-ESI");
    }

    if (req.http.Cookie ~ "redirect_url") {
        hash_data("redirect_url");
    }

    hash_data(req.http.X-Forwarded-Proto);
}

Latest findings after a debug ofcode base

while (!feof($this->socket)) {
            if (($response = fgets($this->socket, 1024)) === false) {
                $metaData = stream_get_meta_data($this->socket);
                              
                if ($metaData['timed_out']) {
                    throw new RuntimeException('Varnish CLI timed out');
                }
                
                throw new RuntimeException('Unable to read from Varnish CLI');
            }

            if (strlen($response) === 13 && preg_match('/^(\d{3}) (\d+)/', $response, $matches)) {
                $statusCode = (int) $matches[1];
                $responseLength = (int) $matches[2];
                break;
            }
        }

fgets($this->socket, 1024) return values incase of varnish installed as a service in application container

fgets($this->socket, 1024) return false incase of varnish installed as a seperate container

docker-compose.yml

version: '3.7'
services:
  dev:
    image: xxxxxxx/dev:centos7
    container_name: dev
    hostname: dev
    volumes:
      - ${HOST_BIND_MOUNT_DIR}:${CONTAINER_MOUNT_DIR}
      - /sys/fs/cgroup:/sys/fs/cgroup:ro
    privileged: true
    networks:
      dev-online:
        ipv4_address: 172.100.0.2
    ports:
      - 443:443
     #- 6082:6082
     #- 9001:9001
     #- 5672:5672
     #- 15672:15672
      - 29015:29015
    extra_hosts:
      - dev:127.0.0.1
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11

  dev-mysql:
    image: xxxxxxx/mysql-5.6:dev
    container_name: dev-mysql
    hostname: dev-mysql
    user: "${V_UID}:${V_GID}"
    volumes:
      - ${HOST_BIND_MOUNT_DIR_MYSQL}:${CONTAINER_MOUNT_DIR_MYSQL}
    networks:
      dev-online:
        ipv4_address: 172.100.0.3
    ports:
      - 3306:3306
    environment:
      - MYSQL_ROOT_PASSWORD:${MYSQL_ROOT_PASSWORD}
      - MYSQL_DATABASE:${MYSQL_DATABASE}
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:127.0.0.1
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11

  dev-mongo-3:
    image: xxxxxxx/mongo-3.0:dev
    container_name: dev-mongo-3
    hostname: dev-mongo-3
    volumes:
      - ${HOST_BIND_MOUNT_DIR_MONGO_3}:${CONTAINER_MOUNT_DIR_MONGO}
    privileged: true
    networks:
      dev-online:
        ipv4_address: 172.100.0.4
    ports:
      - 27017:27017
    environment:
      - MYSQL_ROOT_PASSWORD="${MYSQL_ROOT_PASSWORD}"
      - MYSQL_DATABASE="${MYSQL_DATABASE}"
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:127.0.0.1
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11

  dev-mongo-4:
    image: xxxxxxx/mongo-4.4:dev
    container_name: dev-mongo-4
    hostname: dev-mongo-4
    user: "${V_UID}:${V_GID}"
    volumes:
      - ${HOST_BIND_MOUNT_DIR_MONGO_4}:${CONTAINER_MOUNT_DIR_MONGO}
    privileged: true
    networks:
      dev-online:
        ipv4_address: 172.100.0.5
    ports:
      - 27018:27017
    environment:
      - MYSQL_ROOT_PASSWORD="${MYSQL_ROOT_PASSWORD}"
      - MYSQL_DATABASE="${MYSQL_DATABASE}"
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:127.0.0.1
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11

  dev-solr-6:
    image: xxxxxxx/solr-6.6:stable
    container_name: dev-solr-6
    hostname: dev-solr-6
    networks:
      dev-online:
        ipv4_address: 172.100.0.6
    ports:
      - 8983:8983
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:127.0.0.1
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11

  dev-solr-8:
    image: xxxxxxx/solr-8.6:dev
    container_name: dev-solr-8
    hostname: dev-solr-8
    user: "${V_UID}:${V_GID}"
    volumes:
      - ${HOST_BIND_MOUNT_DIR_SOLR}:${CONTAINER_MOUNT_DIR_SOLR_8}
    networks:
      dev-online:
        ipv4_address: 172.100.0.7
    ports:
      - 8984:8983
    environment:
      - SOLR_HEAP=2g
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:127.0.0.1
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11

  dev-rethinkdb:
    image: rethinkdb
    container_name: dev-rethinkdb
    hostname: dev-rethinkdb
    user: "${V_UID}:${V_GID}"
    volumes:
      - ${HOST_BIND_MOUNT_DIR_RETHINKDB}:${CONTAINER_MOUNT_DIR_RETHINKDB}
    networks:
      dev-online:
        ipv4_address: 172.100.0.8
    ports:
      - 28015:28015
      - 8080:8080
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:127.0.0.1
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11
      
  dev-memcached:
    image: memcached
    container_name: dev-memcached
    hostname: dev-memcached
    user: "${V_UID}:${V_GID}"
    networks:
      dev-online:
        ipv4_address: 172.100.0.9
    ports:
      - 11211:11211
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:127.0.0.1
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:172.100.0.11

  dev-varnish:
    image: varnish:7.3.0-alpine
    container_name: dev-varnish
    hostname: dev-varnish
    user: '0'
    volumes:
      - "./default.vcl:/etc/varnish/default.vcl:ro"
      - "./secret:/etc/varnish/secret"
    ports:
      - "8081:80"
    tmpfs:
      - /var/lib/varnish/varnishd:exec
    networks:
      dev-online:
        ipv4_address: 172.100.0.10
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-varnish:127.0.0.1
      - dev-memcached:172.100.0.9
      - dev-rabbitmq:172.100.0.11

  dev-rabbitmq:
    image: rabbitmq:3.9.27-management-alpine
    container_name: dev-rabbitmq
    environment:
            RABBITMQ_DEFAULT_PASS: ${RABBITMQ_DEFAULT_PASS}
            RABBITMQ_DEFAULT_USER: ${RABBITMQ_DEFAULT_USER}
            RABBITMQ_DEFAULT_VHOST: ${RABBITMQ_DEFAULT_VHOST}
    volumes:
      - ${HOST_BIND_MOUNT_DIR_RMQ}/data:${CONTAINER_MOUNT_DIR_RMQ}
      - ${HOST_BIND_MOUNT_DIR_RMQ}/log:/var/log/rabbitmq
    ports:
      - "5672:5672"
      - "15672:15672"
    networks:
      dev-online:
        ipv4_address: 172.100.0.11
    extra_hosts:
      - dev:172.100.0.2
      - dev-mysql:172.100.0.3
      - dev-mongo-3:172.100.0.4
      - dev-mongo-4:172.100.0.5
      - dev-solr-6:172.100.0.6
      - dev-solr-8:172.100.0.7
      - dev-rethinkdb:172.100.0.8
      - dev-memcached:172.100.0.9
      - dev-varnish:172.100.0.10
      - dev-rabbitmq:127.0.0.1

networks:
  dev-online:
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: 172.100.0.0/24

Same 503/500 error after adding below configuration

application configuration in dev container

'endpoint' => [
                    'host' => '172.100.0.10',
                    'port' => '6082',
                    'secret' => 'xxxxxxxxxxxxxxxxxxxxxx',
                ]
            

added below command to varnish container in docker-compose.yml

command: ["-T",":6082","-S","/etc/varnish/secret"]

The dev-varnish container belo

 /etc/varnish # ps aux
    PID   USER     TIME  COMMAND
        1 varnish   0:00 varnishd -F -f /etc/varnish/default.vcl -a http=:80,HTTP -a proxy=:8443,PROXY -p feature=+http2 -s malloc,100M -T :6082 -S /etc/varnish/secret
       18 varnish   0:01 {cache-main} varnishd -F -f /etc/varnish/default.vcl -a http=:80,HTTP -a proxy=:8443,PROXY -p feature=+http2 -s malloc,100M -T :6082 -S /etc/varnish/secret

---

docker top dev-varnish
UID                 PID                 PPID                C                   STIME               TTY                 TIME                CMD
systemd+            17596               17547               0                   07:57               ?                   00:00:04            varnishd -F -f /etc/varnish/default.vcl -a http=:80,HTTP -a proxy=:8443,PROXY -p feature=+http2 -s malloc,100M -T :6082 -S /etc/varnish/secret
systemd+            17928               17596               0                   07:57               ?                   00:00:28            varnishd -F -f /etc/varnish/default.vcl -a http=:80,HTTP -a proxy=:8443,PROXY -p feature=+http2 -s malloc,100M -T :6082 -S /etc/varnish/secret

---

/etc/varnish # varnishadm -T 172.100.0.10:6082 -S /etc/varnish/secret
200        
-----------------------------
Varnish Cache CLI 1.0
-----------------------------
Linux,5.15.0-71-generic,x86_64,-junix,-smalloc,-sdefault,-hcritbit
varnish-7.2.1 revision 399fa7ed46d68f4c4f42a8fd2748339750d99a8b

Type 'help' for command list.
Type 'quit' to close CLI session.

varnish>

---

[root@dev www]# telnet 172.100.0.10 6082
Trying 172.100.0.10...
Connected to 172.100.0.10.
Escape character is '^]'.
107 59      
tbdxujqstyqxpnpjwhlbmhdjmiudnuib

Authentication required.

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
101 44      
Unknown request.
Type 'help' for more info.

working configuration, when varnish runs inside dev container

997                 114389              112718              0                   20:07               ?                   00:00:00            /usr/sbin/varnishd -a 127.0.0.1:80 -f /etc/varnish/default.vcl -T 127.0.0.1:6082 -t 120 -p thread_pool_min=10 -p thread_pool_max=500 -p thread_pool_timeout=120 -p feature=+esi_disable_xml_check -p pipe_timeout=600 -p timeout_idle=301 -S /etc/varnish/secret -s malloc,256M -n xxxx-cache

non-working configuration, when varnish runs as separate container

systemd+            116915              116892              0                   20:18               ?                   00:00:00            varnishd -F -f /etc/varnish/default.vcl -a http=:80,HTTP -a proxy=:8443,PROXY -p feature=+http2 -s malloc,100M -T :6082 -S /etc/varnish/secret

Answer 1

You need to make Varnish CLI traffic available from outside the dev-varnish container.

You can achieve this by adding the following line to the dev-varnish container in your docker-compose.yml file:

command: ["-T",":6082","-S","/etc/varnish/secret"]

This will open up port 6082 on all network interfaces for CLI traffic. The CLI traffic will be protected through the /etc/varnish/secret file which is already mounted in the container.

After having enabled global CLI support in your Docker setup, you can connect to the CLI endpoint from your application with the following parameters:

• Host: 172.100.0.10
• Port: 6082

Please ensure that the secret file is also mounted in your dev container and that your code can handle the authentication challenge that leverages the secret file.

Answer 2

Hum...

did you see that your application is throwing a 500 HTTP error ?

-   BerespStatus   500
-   BerespReason   Internal Server Error

The application container log is probably not the log that helps in your case.. it refers to an HTTP connection (and you probably don't have HTTPS between varnish and your application)... and the requesting IP (172.100.0.1) is not the varnish container IP (172.100.0.10). you're probably looking into the proxy container log, that appears to be on top of your varnish configuration.