keep nodejs server on azure VM running - node.js

I have a Windows Azure VM(linux server 14.04) running and am able to access the VM using command line on my mac/windows machines. I'm running a node.js server and a mongodb instance on this Azure VM.
The problem is that this nodejs server on the VM gets disconnected after sometime(timeout sort of thing). Is it possible that the server on the VM runs indefinitely and keeps serving requests?
PS: My VM is running indefinitely and properly, but the nodejs server on the VM itself times out after sometime. Please help!
Thanks.

It is probably just crashing!
A barebone node application does not get monitored by itself.
This might sound a little crazy if you come from other web frameworks / platforms like ASP.NET or PHP where you had IIS or Apache monitoring your application for you, which was kind of nice tbh. In node.js you choose your process manager / monitoring system. From my experience, the most popular and well supported PMs are the ones listed in the Expressjs documentation: http://expressjs.com/advanced/pm.html

As Azure VMs will not sleep or shutdown itself , and also will not stop any servers running on them.
And per your description
the nodejs server on the VM itself times out after sometime
The issue seems the same with what #svenskunganka said.
You can check what occurred the error “sometime”, leveraging PM2 as #Daniel and #svenskunganka suggested.
When you deploy your nodejs project with PM2, it will monitor the application and log errors automatically. You can also monitor your VM metrics (such as CUP Usage,Network in/out) from Azure Portal Monitor panel.

Related

ASP.NET Core IHostedService stops when hosted on linux

I have an ASP.NEt Core 3.1 application with Angular 8 frontend. It runs fine when hosted on IIS but as I have moved it onto a new Ubuntu 18 Server with Nginx above Kestrel sometimes the long running background processes stop working (IHostedService). Then the app runs towards accepting new requests so only the background process is stopped.
These processes get files from clients and give immediate responses with a process ids. The clients can query the process state by their id. Everything have been running fine for months now on IIS but the new config must have some limits that kills these processes. I suppose there is some kestrel or nginx option I don't know about and affect processes started by http requests.
What options can I try and where can I get some logs?
I've tried to log everything from .net core but even the most verbose logs are useless here. Nginx logs doesn't contain any info about the stopped process either.
Although the application runs fine hosted on IIS I tried to find catch blocks without any output and added logging into them but still nothing. Are there anything I can add to my application globals to log any exceptions handled or unhandled?
I forgot to say that I use a local Microsoft SQL Server Express both on windows and linux. The linux Sql Server install was done by the official ms docs (as dotnet and nginx config, too). The database is restored from a windows sql server backup. The connection string is the same with multipleresultsets=true. Are there any differences I should aware of?
For anyone getting here in the future: this was caused by a bug in Microsoft.Data.SqlClient, so I had to update it (independently from EF Core 3.1.2) from nuget to the newer 1.1.2 version.
When it stucked I had two threads waiting for each other, both in SqlClient. With Just my code enabled VS debugger stopped at one of my linq queries. The only interesting part was that it never threw any exceptions and there was no deadlock event on the sql server either. It just waited there so all logs were empty.
https://github.com/dotnet/efcore/issues/18480
https://github.com/dotnet/SqlClient/issues/262

Deploy node.js in production

What are the best practices for deploying a nodejs application in production?
I would like to know how deploy for production Api's nodejs is being done today, today my application is in docker and running locally.
I wonder if I should use a Nginx inside the container and deploy my server on it or just upload my image node that is already running today.
*I need load balance
There are few main types of deployment that are popular today.
Using platform as a service like Heroku
Using a VPS like AWS, Digital Ocean etc.
Using a dedicated server
This list is in the order of growing difficulty and control. So it's easiest with PaaS but you get more control with a dedicated server - thought it gets significantly more difficult, especially when you need to scale out and build clusters.
See this answer for more details on how to install Node on a VPS or a dedicated server:
how to run node js on dedicated server?
I can only add from experience on AWS using a NAT Gateway which is a dedicated Node server with a MongoDB server behind the gateway. (Obviously this is a scalable system and project.)
With or without Docker, you need to control the production environment. This means clearly defining which NPM libraries you will need for production, how you handle environment variables and clusters for cores.
I would suggest, very strongly, using a tool like PM2 to handle clusters, server shutdowns and restarts and logs. (Workers & slaves also if you need them and code for them).
This list can go on and on, but keep in mind this is only from an AWS perspective. Setting up a Gateway correctly on AWS is also not an easy process. Be prepared for some gotcha's along the way.

Deploy a MEAN stack application to an existing server

I have a Ubuntu Server on DigitalOcean which hosts a website, and a Windows Server on AWS which hosts another website.
I just built a mean.js stack app on my MAC, and I plan to deploy it to production.
It seems that most of the existing threads discuss about using a new dedicated server. For example, this thread is about deploying on a new AWS EC2 instance; this video is about deploying on a new Windows Azure server; this is to create a new droplet in DigitalOcean.
My question is, is it possible to use an existing server (which hosts other websites), rather than creating a new server? If yes, will there be any difference in terms of performance?
My question is, is it possible to use an existing server (which hosts other websites), rather than creating a new server?
Yes. Both Windows and Ubuntu allows you to deploy multiple applications on same instance.
For Ubuntu you can read this post which will help you server multiple apps.
In this example used Nginx, but you can follow to this example and use it without any server like Apache or Nginx. If you need subdomains I would suggest to use Apache virtual hosts with reverse proxy module and pm2
For Windows and its IIS I would suggest to use iisnode, in google you can find a lot of articles how to configure it.
will there be any difference in terms of performance?
It is depended on your applications, if you are already serving applications which handles huge traffic and need CPU and memory, I would not suggest you to use multiple apps on same instance, but if you are going to use simple web apps, you can easily use same instance.
Hope this answer will help you!

NodeJs not staying live in aws

I have deployed a Bitnami AMI of NodeJS on an AWS micro instance. After starting my node app, everything works fine.
After some time without any activity, the app which is attached to port :3000, seems to shut down. When this happens on refreshing the page my browser gives the message:
Network Error (tcp_error)
A communication error occurred: "Connection refused"
The Web Server may be down, too busy, or experiencing other problems preventing it from responding to requests. You may wish to try again at a later time.
The AWS console shows the instance is still running and the Bitnami build still responds with the standard message on port 80.
Forever (https://github.com/nodejitsu/forever) is also a useful tool for this kind of thing, and it gives you a little more control than nohup or screen.
As we discussed in comments, the problem was binding the node process to SSH session.
You can use nohup or screen to launch the node process in an instance not bound to session.
I suggest using screen because the function of returning to launched instance is essential for maintenance/updating.
Related: How to run process as background and never die
Related: Command-Line Interface tool to run node as a service
Besides configuring an EC2-instance you can also use the PaaS-solution of AWS, namely Elastic Beanstalk. They have also support for Node.js and it's super easy to deploy your apps using this service.

Best solution to host a (command line) Windows application?

I have a Windows application that does some calculations and is called from command line. On my Windows machine, I have a PHP script running under Apache that executes the application and shows the output.
Is there any hosting solution that I can use to do the same? I can't figure out if EC2 or Azure are the right solutions. Basically, I need a web server + ability to execute my application.
Suggestions? Thanks.
You can host your application on AppHarbor, the .NET Platform-as-a-Service. You can either port your web frontend to .NET or try to get your PHP stuff working with Phalanger. AppHarbor is working on Background Tasks, which might be a good match for your workload.
I would just run the PHP script you already have under IIS in a Windows Azure web role.
If it is a Windows Application and you have the source code I would go with an Azure Worker Role. The advantage of using a PaaS (as Azure) instead of an IaaS (as Amazon) is that you wont have to bother of keeping the server up to date.
The real investment in time will be when you rewrite your application to make it work as a Worker Role. The time needed to do this work depends on how your application works right now. If is uses a lot of disc access it might be difficult and perhaps an Amazon server would be better. But if it only crunches numbers in memory an Azure Worker Role is a very good candidate.
The real advantage of using an Amazon server is that you probably wont need to do any work at all. Except maintaining the server.
As described in the question both Azure and EC2 will do the job very well. This is the kind of task both systems are designed for.
So the question becomes really: which is best? That depends on two things: what the application needs to do and your own experience and preference.
As it's a Windows application there should probably be a leaning towards Azure. While EC2 supports Windows, the tooling and support resources for Azure are probably deeper at this point.
If cost is a factor then a (somewhat outdated) resource is here: http://blog.mccrory.me/2010/10/30/public-cloud-hourly-cost-comparison/ -- the conclusion is that, by and large, Azure and Amazon are roughly similar for compute charges.
Steve Marx has a blog post that describes how to run another web server (i.e not IIS) on Azure
This potentially has everything you need - you can deploy Apache and your executable and run it in exactly the same way.
Alternatively - you can deploy your executable along side a bit of code in a worker role that would run that application periodically, all depending on your exact requirements

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