Wondering if we can share session data between two servers (running different code) behind an Nginx reverse proxy.
To be precise, we have a legacy app in PHP running on an apache server. We are updating some functionality and hosting only that functionality on a separate server (nginx). Both apps update the same DB.
nginX uses load balancing/ reverse proxy URL rewritting techniques to decide which server to send the client to based on the URL path they use.
So, a person can add items to his virtual basket (held in session) on
the new server application.
He then decides to edit his personal information which is on the other server (Legacy).
Nginx uses it's reverse proxy/load balancing magic to decide which server to send the person to based on where an app is available.
The question is, how can a session created on one app server be available to another app server aswell? is it possible to setup the reverse proxy to store all session data and how. Please point me to the right direction of you can help with google links aswell.
your question has several possible answers. It all depends on the way the application is designed.
A possible scenario would be to keep session information on a database shared among different web heads. In this way the client, once authenticated will retrieve its "session status" regardless which server he is accessing in the final servers cluster backend.
Again, this depends very much on the way the application is/has been designed.
I think there is very little magic you can do on an old legacy application just by configuring the reverse proxy engine.
In the end, sessions are handled by the application server and not the proxy frontend.
Related
I basically have an API that is going to be used with a web app and a mobile app. I don't want the API to publically available, where should I deploy it then? is there a way without using AWS? Thanks, Nav :)
There are multiple ways of doing this. This is a sensitive topic, as this is an opinion-based field.
However, I will try to answer below - and challange your way of approaching this.
It really depends on your 'operational' skills, funds, need for security, deadline(s) etc.
Basically you need to make an endpoint available on the www, without everybody being able to connect.
You could either:
Deploy a virtual machine or web app. in Azure/AWS/GCP/... and whitelist the IP's you need to connect from.
Rent a VPS from any provider, and deploy your application here - Again, whitelisting. (Edit: Not phones, since this IP changes constantly. A proxy can be implemented here (potential bottleneck), or any authentication mechanism like OAuth, JWT, Certificates etc. can be implemented either on the ingress controller (e.g. NGINX) or the application itself.)
Deploy the application on your Home-PC, order a static IP to your home and make a forwarded port and set up security on your premise (not recommended, and raises and bunch of other headaches)
Get in touch with a company that hosts web applications (Can be quite expensive)
Based on the limited information provided in your question, there is a ton of options, nice-2-haves and factors that comes in to play when choosing the setup that suits your needs.
You should also consider; VPN usage, Backup/disaster recovery, data leaks, redundancy, the need for future deploys, how you would access your environment in six months....
I hope this answered your question, but also raised a few for you to answer yourself.
Finally, I'd recommend you looking for inspiration here.
EDIT:
Question:
Whitelisting mobile IP's.
VPS selected.
Answer:
This becomes quite a task when mobile phones tend to change IP's frequently.
Since you are looking further into the VPS setup, you are more in control of the setup and can choose to look into OAuth and JWT.
Links:
OAuth - https://oauth.net/getting-started/ https://developer.okta.com/blog/2019/01/22/oauth-api-keys-arent-safe-in-mobile-apps
NGINX JWT - https://docs.nginx.com/nginx/admin-guide/security-controls/configuring-jwt-authentication/
So - At the end of the day, you can make your app use a proxy (potential bottleneck) and whitelist this IP, or make the endpoint open (any -> 443) and implement an authentication mechanism like the ones mentioned above.
Consider implementing a DMZ zone for incoming traffic from the web.
https://en.wikipedia.org/wiki/DMZ_(computing)
and put your application behind this zone, making sure that the only the DMZ zone is facing the internet, and the server hosting your application is talking to the server in the DMZ.
Again, this is quite a big topic and is hard to simplify to a stackoverflow post.
If you are hosting the app on AWS you have a couple of options.
API Gateway now supports private endpoints. These endpoints can not be called via the public internet. That means if your app is hosted on AWS only the internal services of the app can call the end point. i.e. front end to database etc. I've used this method for internal micro services such as placing in house app data onto kinesis streams.
Alternatively, if you don't want to use API Gateway you have lots of options. Most of which would involve you creating rest APIs from where ever you plan on hosting your code. This could be on the server it's self or some sort of container.
API Gateway Private Endpoint Reference:
https://aws.amazon.com/blogs/compute/introducing-amazon-api-gateway-private-endpoints/
I have recently installed PHP, MySQL Server, and Apache web server. I played around with some PHP scripts locally on the PC to insert some entries to MySQL Database.
Noob question so please be patient with me:
How do I get my web service out to the internet, by self hosting? Say I already have a domain for example mydomain.com How do I make it so that when someone not within my network can access mydomain.com/something and can send some data so my server gets it and do anything with that data?
Webhosting
You have to have some form of webhosting. You pay for hosting and you can upload your PHP files to their servers. They will usually also have database servers you can use.
Your domain name has to point to those servers via DNS so the internet can reach your application. I'd suggest you search the internet for popular hosts that provide the tools your need for this.
Self hosting
Another possibility is to open your network up to the world, but this is not recommended unless you have network administration experience due the security trouble that comes with it.
In short: forward a port through your router to the machine running your application. The website portforward.com has instructions on how to do this but keep in mind that misconfiguration could lead to vulnerabilities in your network.
In order to make you site public
1. you need host
2. you need domain
there are bunch of hosting sites you should get one first.
This link explains very well about self hosting
https://www.boutell.com/newfaq/creating/hostmyown.html
I am developing an app (RoR + Heroku) which allows users create their own websites either using my subdomain (pagename.myapp.com) or using their own domain (pagename.com).
An important point of this is that this option is the key of my business: subdomains are the free plans and custom domains are the paid ones. So I have a table where I store the custom domains of each user and check if this page is active (exists and has paid the quota).
For that I need to give users the capability of point their domain to my servers. All we know that Heroku don't recommend the use of DNS A-Records.
Also I would like to abstract as much as possible this feature to being able to switch my infrastructure (Heroku to AWS) in the future without having to ask all my users to change their DNS Zone. Taking this into account, I think that the best option would be run something like an EC2 proxy (using AWS Elastic IP) which give me the ownership of this IP. This proxy I think that should redirect to proxy.myapp.com, and I would resolve the request in the app level.
Due to I didn't find clear information about that, I am not sure if this hypotesis is the best solution and how to setup the proxy (which type of proxy use? Nginx maybe?).
Said that, I would like to ask recommendations/best practices to solve this "common" feature.
Thanks
What you are wanting to do is fairly straight forward to implement. Your assumptions are correct about setting up the proxy. Nginx or haproxy will both work great for this (I personally would use haproxy). Here are some of the gotchas that you will run into though:
Changing the host header at a proxy server can cause the end web application to generate incorrect links. You can use relative paths to fix this, but it requires that the web application developer to be aware of the environment that they are running in.
user connects to www.example.com (proxy server)
proxy server connects to www.realdomain.com (web app)
the web app has a link for a shopping cart. www.realdomain.com/shoppingcart
the end user clicks on the link but the link is www.realdomain.com/shoppingcart instead of www.example.com/shoppingcart
The cost of the host acting as the proxy server. This can spiral out of control really quickly. For example, do you want redundancy, if so how are you planning on implementing that? Do you plan on having ssl termination? If so you will have to increase the CPU count to accommodate the additional load. Do you want to have a secure connection to heroku from your proxy? If you do then you will need to increase the CPU count for that as well. You may have to add additional ram as well depending on the number of concurrent connections.
Heroku also changes their load balancers regularly. This is important because your proxy service will need to reload the config / update the ip addresses of the heroku instances every 60 seconds. In my experience they may change once or twice a day, but the DNS entry that they use has a 60 second TTL. That means that you should make sure that you are capable of updating your config up to every 60 seconds.
My company has been doing something very similar to this for almost a year now. We use haproxy and simply have it reload the config regularly. We have never had an outage or an interruption to our end users. Nginx is also a very good product. It has built in DNS caching so if you go that route you will need to make sure that you configure it correctly so that the DNS cache TTL is 60 seconds.
Will many of your clients want to use your app on their domain apex? E.g. example.com rather than theapp.example.cpm? If not, I would recommend having them CNAME to proxy.myapp.com which CNAMEs to myapp.herokuapp.com. Then, you can update proxy.myapp.com without customer interruption.
If you do need apex or A record support, you would want to set up Nginx as a reverse proxy for your Heroku app. Keep in mind that if you need HTTPS support for client domains, you will need to do some sort of certificate management on your proxy.
I like the answer dtorgo gave and that he mentioned the TLS termination, which many online tutorials on custom domains don't touch at all.
I'll go into more detail on how to implement the custom domains feature for your SaaS while also handling the TLS/HTTPS.
If your customers just CNAME to your domain or create the A record to your IP and you don't handle TLS termination for these custom domains, your app will not support HTTPS, and without it, your app won't work in modern browsers on these custom domains.
You need to set up a TLS termination reverse proxy in front of your webserver. This proxy can be run on a separate machine but you can run it on the same machine as the webserver.
CNAME vs A record
If your customers want to have your app on their subdomain, e.g. app.customer.com they can create a CNAME app.customer.com pointing to your proxy.
If they want to have your app on their root domain, e.g. customer.com then they'll have to create an A record on customer.com pointing to your proxy's IP. Make sure this IP doesn't change, ever!
How to handle TLS termination?
To make TLS termination work, you'll have to issue TLS certificates for these custom domains. You can use Let's Encrypt for that. Your proxy will see the Host header of the incoming request, e.g. app.customer1.com or customer2.com etc., and then it will decide which TLS certificate to use by checking the SNI.
The proxy can be set up to automatically issue and renew certificates for these custom domains. On the first request from a new custom domain, the proxy will see it doesn't have the appropriate certificate. It will ask Let's Encrypt for a new certificate. Let's Encrypt will first issue a challenge to see if you manage the domain, and since the customer already created a CNAME or A record pointing to your proxy, that tells Let's Encrypt you indeed manage the domain, and it will let you issue a certificate for it.
To issue and renew certificates automatically, I'd recommend using Caddyserver, greenlock.js, OpenResty (Nginx).
tl;dr on what happens here;
Caddyserver listens on 443 and 80, it receives requests, issues, and renews certificates automatically, proxies traffic to your backend.
How to handle it on my backend
Your proxy is terminating TLS and proxying requests to your backend. However, your backend doesn't know who is the original customer behind the request. This is why you need to tell your proxy to include additional headers in proxied requests to identify the customer. Just add X-Serve-For: app.customer.com or X-Serve-For: customer2.com or whatever the Host header is of the original request.
Now when you receive the proxied request on the backend, you can read this custom header and you know who is the customer behind the request. You can implement your logic based on that, show data belonging to this customer, etc.
More
Put a load balancer in front of your fleet of proxies for higher availability. You'll also have to use distributed storage for certificates and Let's Encrypt challenges. Use AWS ECS or EBS for automated recovery if something fails, otherwise, you may be waking up in the middle of the night restarting machines, or your proxy manually.
If you need more detail you can DM me on Twitter #dragocrnjac
Heroku offers US and EU servers and I want my users to connect to the server which is closer to them, so if someone connects from the EU, I will redirect them to the EU server and the same for the US.
My idea was to have them connect to main domain name, example.com that would connect to the US server, which would check where the users are coming from, and then redirect them to where I want them to be, and all this while they are looking at the same domain "example.com". Heroku wont let me add the same domain twice, and I don't know where I should configure what for the DNS. My domain provider has a nameserver section and I'm not sure what to add there. Basically I want all the request and server load to go onto the Heroku page, and not onto the default DNS server which only redirects or loads the Heroku page inside a frame.
They way it seems correct, is to connect to example.com, which is the US Heroku page and then redirect inside a frame or something to the EU page... not sure if this is the best way, and like I mentioned, I'm not sure how to setup the namespace and stuff so they connect directly to the Heroku server instead of the default domain server.
Could someone explain to me what I need to do to achieve what I want?
It is currently not possible to run a multi-region application on Heroku and I'd caution against trying to work your way around this limitation. Some areas that cause users problems when trying to attempt this are:
You can't have the same custom domain on two apps (as you've already identified).
There is no way to setup a multi-master database configuration so each app has a db in its own region. Likewise, maintaining a single master for both apps results in very high latency for one of the apps.
The connection overhead of any other trickery, like what you propose here, often negates any latency improvement the user sees from accessing the app in their closest region.
Using a CDN for static assets, and having a proper http cache header strategy often gets you 90% of the way to the performance of a truly geo-distributed app.
To drill further into your question, I'm not sure what you mean here?
how to setup the namespace and stuff so they connect directly to the Heroku server instead of the default domain server
Hope that helps!
We're building a multitenant SAAS app. Each customer gets its own subdomain, http://customername.mycompany.com. Each customer will have many gigabytes of data, which means that they have to be assigned to a particular server and stay there.
If I have a server farm, and a request comes in for a particular customer, how do I direct the request to the right server?
My thought is that I'll have to create some kind of custom, programmable load balancer that will know where each customer lives and proxy the request through.
Is there an easier way?
If not, where do I find such a load balancer? The ones I've found online act more like appliances than applications which could go query a database to find the right destination server.
I think the answer is in the question; you mention that the user will connect to username.mycompany.com. So use a DNS A record to point them to a particular IP.
In the future, if you wanted to load balance the user across (say 2) servers, you could create a virtual IP on a load balancer appliance (running LVS for example), and then point the A record to the Virtual IP created by the LB, and distribute the user across a group of servers that you have configured.
This is why using subdomains is simpler than having URL based access such as company.com/username, in which case you would have to inspect the content of the packet to see the requested URL. By using subdomains, everything can be done at the IP layer.