id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
2128	Using a variable in the resolver directive	avsdev-cw@…		"TLDR: `My request is that the resolver directive be capable of supporting variables.`

Currently I am required to run services on different networks which have different subnets and may have different stand-alone DNS servers (some of which are dynamic DNS servers).

I am using nginx as a reverse proxy on a host which has multiple nics allowing it to connect to hosts of the various networks.

This main host has a common configuration file for proxying (reducing the overhead of managing multiple proxied hosts) and utilises a variable to pass into the proxy_pass directive. Currently the common configuration file has a ""resolver"" directive indicating the DNS server to use to resolve the proxy_pass host.

This works great when only 1 DNS server on 1 subnet is required, however some of the upstream hosts are on a different subnet with a different DNS configuration and their own DNS server.

Currently the ""resolver"" directive produces an [emerg] level error when attempting to use a variable as the host:
{{{
nginx: [emerg] host not found in resolver ""$resolver_ip"" in /etc/nginx/proxy_config:20
}}}
which leads me to believe that the directive does not support variables. In addition, it appears the resolver directive cannot be overridden and must be used once and only once in server block."	enhancement	closed	minor		nginx-module	1.19.x	wontfix			Linux web-proxy 5.8.0-0.bpo.2-amd64 #1 SMP Debian 5.8.10-1~bpo10+1 (2020-09-26) x86_64 GNU/Linux	"nginx version: nginx/1.14.2
built with OpenSSL 1.1.1d  10 Sep 2019
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fdebug-prefix-map=/build/nginx-Cjs4TR/nginx-1.14.2=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_addition_module --with-http_geoip_module=dynamic --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module=dynamic --with-http_sub_module --with-http_xslt_module=dynamic --with-stream=dynamic --with-stream_ssl_module --with-stream_ssl_preread_module --with-mail=dynamic --with-mail_ssl_module --add-dynamic-module=/build/nginx-Cjs4TR/nginx-1.14.2/debian/modules/http-auth-pam --add-dynamic-module=/build/nginx-Cjs4TR/nginx-1.14.2/debian/modules/http-dav-ext --add-dynamic-module=/build/nginx-Cjs4TR/nginx-1.14.2/debian/modules/http-echo --add-dynamic-module=/build/nginx-Cjs4TR/nginx-1.14.2/debian/modules/http-upstream-fair --add-dynamic-module=/build/nginx-Cjs4TR/nginx-1.14.2/debian/modules/http-subs-filter
"