How test if varnish is working (HIT or MISS) - nginx

I added in varnish file "default.vcl" a code for check if Varnish cache is working but I get a Transfer-Encoding "Chunked" and I cant see if Cache is working displaying HIT or MISS. I follow next tutorial and I believe have some port in nginx blocking his right function.
Code added within of "sub vcl_deliver":
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT";
} else {
set resp.http.X-Cache = "MISS";
}
My settings:
Apache 2.4.6 port by default 7080
etc/nginx/nginx.conf without port by default (without port added)
etc/nginx/plesk.conf.d/server.conf > server listen port MyIP:80 (default)
Varnish port 80 to external 32780 (Added from plesk)
etc/varnish/default.vcl: In host my IP and in port 7080
How can delete "Transfer-Encoding Chunked" and remplace it for "X-Cache MISS or HIT" to show in headers ?
Best regards

Related

roku sending request, but nginx not responding or logging

I am trying to display a series of short mp4's on my Roku. The idea is to serve them from nginx running on a local host. The Roku hangs on "retrieving" the video. I have used wireshark to witness the requests coming from the roku, and they continuously repeat. Though nginx does not respond, nor does it log the request in access.log or error.log.
I feel that the roku scripts are sufficiently coded as I can confirm that the playlist is received by the video node, the screen is focused, and the request for the video is being made through port 80. I can request the url through a browser and the mp4 plays in the browser if made with http: or in a player if made with rtmp:.
This is the simple nginx configuration in conf.d;
server {
listen 80 default_server;
location / { # the '/' matches all requests
root /myNginx/sites; # the request URI would be appended to the root
index 01_default_test.html; # the index directive provides a default file or list of files to look for
}
location /videos/ { # for testing use 'http://10.0.0.13/videos/sample.mp4'
mp4; # activates the http_mp4 module for streaming the video
root /VODs; # allows adding 'videos' to the uri and the file name
}
}
}
I appended this to the nginx.conf file;
rtmp {
server {
listen 1935;
chunk_size 4000;
# Video on demand
application VOD { # rtmp://10.0.0.13/VOD/sample03.mp4
play /VOD/videos/;
}
}
Not sure where to go from here. Does anyone know why nginx seems to be ignoring the requests? I am using Ubuntu, and the firewall is currently inactive.

websockets in openresty proxy

I created proxy with MFA using OpenResty, it mainly works ok.
But I have problem with websockets: Firefox says that it "cannot connect with server wss://...". Looking in browser's network panel I can see switching protocols request that seems be ok. My nginx.conf looks as bellow:
worker_processes auto;
env TARGET_APPLICATION_HOST;
env TARGET_APPLICATION_PORT;
env TARGET_USE_SSL;
events {
worker_connections 1024;
}
http {
server {
listen 80;
server_name localhost;
location / {
resolver local=on ipv6=off valid=100s;
content_by_lua_block {
local http = require "resty.http"
local httpc = http.new()
httpc:set_timeout(500)
local ok, err = httpc:connect(
os.getenv("TARGET_APPLICATION_HOST"),
os.getenv("TARGET_APPLICATION_PORT"))
if not ok then
ngx.log(ngx.ERR, err)
return
end
if os.getenv("TARGET_USE_SSL") == "TRUE" then
-- Trigger the SSL handshake
session, err = httpc:ssl_handshake(False, server, False)
end
httpc:set_timeout(2000)
httpc:proxy_response(httpc:proxy_request())
httpc:set_keepalive()
}
}
}
}
It is simpler version of production proxy, but returns the same error with websockets. I tried to use proxy with pure nginx and it works ok with websockets, but I need capabilites of OpenResty (proxing different hosts basing of cookie value).
Is there any simple mistake in the above file or OpenResty does not have websocket abilities?
lua-resty-http is a HTTP(S) client libraty, it does not (and probably will not) support the WebSocket protocol.
There is another library for the WebSocket protocol: lua-resty-websocket. It implements both client and server, so it should be possible to write the proxy using this library.
I need capabilites of OpenResty (proxing different hosts basing of cookie value)
ngx.balancer does exactly what you need, check the example and this answer.

Nginx will not start with host not found in upstream

I use nginx to proxy and hold persistent connections to far away servers for me.
I have configured about 15 blocks similar to this example:
upstream rinu-test {
server test.rinu.test:443;
keepalive 20;
}
server {
listen 80;
server_name test.rinu.test;
location / {
proxy_pass https://rinu-test;
proxy_http_version 1.1;
proxy_set_header Connection "";
proxy_set_header Host $http_host;
}
}
The problem is if the hostname can not be resolved in one or more of the upstream blocks, nginx will not (re)start. I can't use static IPs either, some of these hosts explicitly said not to do that because IPs will change. Every other solution I've seen to this error message says to get rid of upstream and do everything in the location block. That it not possible here because keepalive is only available under upstream.
I can temporarily afford to lose one server but not all 15.
Edit:
Turns out nginx is not suitable for this use case. An alternative backend (upstream) keepalive proxy should be used. A custom Node.js alternative is in my answer. So far I haven't found any other alternatives that actually work.
Earlier versions of nginx (before 1.1.4), which already powered a huge number of the most visited websites worldwide (and some still do even nowdays, if the server headers are to be believed), didn't even support keepalive on the upstream side, because there is very little benefit for doing so in the datacentre setting, unless you have a non-trivial latency between your various hosts; see https://serverfault.com/a/883019/110020 for some explanation.
Basically, unless you know you specifically need keepalive between your upstream and front-end, chances are it's only making your architecture less resilient and worse-off.
(Note that your current solution is also wrong because a change in the IP address will likewise go undetected, because you're doing hostname resolution at config reload only; so, even if nginx does start, it'll basically stop working once IP addresses of the upstream servers do change.)
Potential solutions, pick one:
The best solution would seem to just get rid of upstream keepalive as likely unnecessary in a datacentre environment, and use variables with proxy_pass for up-to-date DNS resolution for each request (nginx is still smart-enough to still do the caching of such resolutions)
Another option would be to get a paid version of nginx through a commercial subscription, which has a resolve parameter for the server directive within the upstream context.
Finally, another thing to try might be to use a set variable and/or a map to specify the servers within upstream; this is neither confirmed nor denied to have been implemented; e.g., it may or may not work.
Your scenario is very similar to the one when using aws ELB as uptreams in where is critical to resolve the proper IP of the defined domain.
The first thing you need to do and ensure is that the DNS servers you are using can resolve to your domains, then you could create your config like this:
resolver 10.0.0.2 valid=300s;
resolver_timeout 10s;
location /foo {
set $foo_backend_servers foo_backends.example.com;
proxy_pass http://$foo_backend_servers;
}
location /bar {
set $bar_backend_servers bar_backends.example.com;
proxy_pass http://$bar_backend_servers;
}
Notice the resolver 10.0.0.2 it should be IP of the DNS server that works and answer your queries, depending on your setup this could be a local cache service like unbound. and then just use resolve 127.0.0.1
Now, is very important to use a variable to specify the domain name, from the docs:
When you use a variable to specify the domain name in the proxy_pass directive, NGINX re‑resolves the domain name when its TTL expires.
You could check your resolver by using tools like dig for example:
$ dig +short stackoverflow.com
In case is a must to use keepalive in the upstreams, and if is not an option to use Nginx +, then you could give a try to openresty balancer, you will need to use/implement lua-resty-dns
A one possible solution is to involve a local DNS cache. It can be a local DNS server like Bind or Dnsmasq (with some crafty configuration, note that nginx can also use specified dns server in place of the system default), or just maintaining the cache in hosts file.
It seems that using hosts file with some scripting is quite straightforward way. The hosts file should be spitted into the static and dynamic parts (i.e. cat hosts.static hosts.dynamic > hosts), and the dynamic part should be generated (and updated) automatically by a script.
Perhaps it make sense to check from time to time the hostnames for changing IPs, and update hosts file and reload configuration in nginx on changes. In case of some hostname cannot be resolved the old IP or some default IP (like 127.0.1.9) should be used.
If you don't need the hostnames in the nginx config file (i.e., IPs are enough), the upstream section with IPs (resolved hostnames) can be generated by a script and included into nginx config — and no need to touch the hosts file in such case.
I put the resolve parameter on server and you need to set the Nginx Resolver in nginx.conf as below:
/etc/nginx/nginx.conf:
http {
resolver 192.168.0.2 ipv6=off valid=40s; # The DNS IP server
}
Site.conf:
upstream rinu-test {
server test.rinu.test:443;
keepalive 20;
}
My problem was container related. I'm using docker compose to create the nginx container, plus the app container. When setting network_mode: host in the app container config in docker-compose.yml, nginx was unable to find the upstream app container. Removing this fixed the problem.
we can resolve it temporarily
cd /etc
sudo vim resolv.conf
i
nameserver 8.8.8.8
:wq
then do sudo nginx -t
restart nginx it will work for the momment
An alternative is to write a new service that only does what I want. The following replaces nginx for proxying https connections using Node.js
const http = require('http');
const https = require('https');
const httpsKeepAliveAgent = new https.Agent({ keepAlive: true });
http.createServer(onRequest).listen(3000);
function onRequest(client_req, client_res) {
https.pipe(
protocol.request({
host: client_req.headers.host,
port: 443,
path: client_req.url,
method: client_req.method,
headers: client_req.headers,
agent: httpsKeepAliveAgent
}, (res) => {
res.pipe(client_res);
}).on('error', (e) => {
client_res.end();
})
);
}
Example usage:
curl http://localhost:3000/request_uri -H "Host: test.rinu.test"
which is equivalent to:
curl https://test.rinu.test/request_uri

Varnish + Nginx proxy configuration on plesk

I followed the official tuto for the Varnish via Docker configuration on plesk. https://www.plesk.com/blog/product-t...cker-container
i have a VPS Ubuntu with plesk and many domains.
I followed all steps :
I created a domain test.monserveur.com
I use the Docker image million12/varnish
On the Docker container setting, the mapping redirect the 80 port to the 32780
On plesk for the hosting parameters, the option “SSL/TLS support” and “Permanent SEO-safe 301 redirect from HTTP to HTTPS” are deactivated
I deactived also the security mod for this domain
On the proxy rules of the docker container (/etc/varnish/default.vcl), i put fo the .host test.monserveur.com and .port 7080
On the function sub vcl_deliver, i put :
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT";
} else {
set resp.http.X-Cache = "MISS";
}
I still have a 503 page with a MISS on the header for the page on test.monserveur.com
I can't understand where is the problem. I tried to put on the .host the serveur IP and with a link to another domain of the server. I think it's a problem with a setting but i don't know where.
Thanks in advance
A 503 error response from Varnish means that your Docker container is not configured properly. You should check whether the container and Varnish within the container are running properly. Additionally, the configuration file must have valid syntax and the correct port and IP address of the server have to be set in the configuration file.
Without knowing what you've entered, I cannot give you a better advice! If you follow the tutorial completely, it will work. I've created over 10 working instances while I wrote the text!
PS: Please use the official Plesk forum with more information (also add your configuration file) if you still cannot solve your problem - https://talk.plesk.com/
Have success!

Nginx memcached with fallback to remote service

I can't get Nginx working with memcached module, the requirement is to query remote service, cache data in memcached and never fetch remote endpoint until backend invalidates the cache. I have 2 containers with memcached v1.4.35 and one with Nginx v1.11.10.
The configuration is the following:
upstream http_memcached {
server 172.17.0.6:11211;
server 172.17.0.7:11211;
}
upstream remote {
server api.example.com:443;
keepalive 16;
}
server {
listen 80;
location / {
set $memcached_key "$uri?$args";
memcached_pass http_memcached;
error_page 404 502 504 = #remote;
}
location #remote {
internal;
proxy_pass https://remote;
proxy_http_version 1.1;
proxy_set_header Connection "";
}
}
I tried to set memcached upstream incorrectly but I get HTTP 499 instead and warnings:
*3 upstream server temporarily disabled while connecting to upstream
It seems with described configuration Nginx can reach memcached successfully but can't write or read from it. I can write and read to memcached with telnet successfully.
Can you help me please?
My guesses on what's going on with your configuration
1. 499 codes
HTTP 499 is nginx' custom code meaning the client terminated connection before receiving the response (http://lxr.nginx.org/source/src/http/ngx_http_request.h#0120)
We can easily reproduce it, just
nc -k -l 172.17.0.6 172.17.0.6:11211
and curl your resource - curl will hang for a while and then press Ctrl+C — you'll have this message in your access logs
2. upstream server temporarily disabled while connecting to upstream
It means nginx didn't manage to reach your memcached and just removed it from the pool of upstreams. Suffice is to shutdown both memcached servers and you'd constantly see it in your error logs (I see it every time with error_log ... info).
As you see these messages your assumption that nginx can freely communicate with memcached servers doesn't seem to be true.
Consider explicitly setting http://nginx.org/en/docs/http/ngx_http_memcached_module.html#memcached_bind
and use the -b option with telnet to make sure you're correctly testing memcached servers for availability via your telnet client
3. nginx can reach memcached successfully but can't write or read from it
Nginx can only read from memcached via its built-in module
(http://nginx.org/en/docs/http/ngx_http_memcached_module.html):
The ngx_http_memcached_module module is used to obtain responses from
a memcached server. The key is set in the $memcached_key variable. A
response should be put in memcached in advance by means external to
nginx.
4. overall architecture
It's not fully clear from your question how the overall schema is supposed to work.
nginx's upstream uses weighted round-robin by default.
That means your memcached servers will be queried once at random.
You can change it by setting memcached_next_upstream not_found so a missing key will be considered an error and all of your servers will be polled. It's probably ok for a farm of 2 servers, but unlikely is it what your want for 20 servers
the same is ordinarily the case for memcached client libraries — they'd pick a server out of a pool according to some hashing scheme => so your key would end up on only 1 server out of the pool
5. what to do
I've managed to set up a similar configuration in 10 minutes on my local box - it works as expected. To mitigate debugging I'd get rid of docker containers to avoid networking overcomplication, run 2 memcached servers on different ports in single-threaded mode with -vv option to see when requests are reaching them (memcached -p 11211 -U o -vv) and then play with tail -f and curl to see what's really happening in your case.
6. working solution
nginx config:
https and http/1.1 is not used here but it doesn't matter
upstream http_memcached {
server 127.0.0.1:11211;
server 127.0.0.1:11212;
}
upstream remote {
server 127.0.0.1:8080;
}
server {
listen 80;
server_name server.lan;
access_log /var/log/nginx/server.access.log;
error_log /var/log/nginx/server.error.log info;
location / {
set $memcached_key "$uri?$args";
memcached_next_upstream not_found;
memcached_pass http_memcached;
error_page 404 = #remote;
}
location #remote {
internal;
access_log /var/log/nginx/server.fallback.access.log;
proxy_pass http://remote;
proxy_set_header Connection "";
}
}
server.py:
this is my dummy server (python):
from random import randint
from flask import Flask
app = Flask(__name__)
#app.route('/')
def hello_world():
return 'Hello: {}\n'.format(randint(1, 100000))
This is how to run it (just need to install flask first)
FLASK_APP=server.py [flask][2] run -p 8080
filling in my first memcached server:
$ telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
set /? 0 900 5
cache
STORED
quit
Connection closed by foreign host.
checking:
note that we get a result every time although we stored data
only in the first server
$ curl http://server.lan && echo
cache
$ curl http://server.lan && echo
cache
$ curl http://server.lan && echo
cache
this one is not in the cache so we'll get a response from server.py
$ curl http://server.lan/?q=1 && echo
Hello: 32337
whole picture:
the 2 windows on the right are
memcached -p 11211 -U o -vv
and
memcached -p 11212 -U o -vv

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