Is it possible at flash media server, to start an application automatically when the server starts?
Or a way to check if it running, and if it's not, make it start automatically.
Yes, I believe it's <LoadOnStartup>true</LoadOnStartup> in Application.xml. You may also want to set MaxAppIdleTime to something appropriately large for your app, lest FMS unload it shortly after startup if no clients have connected.
Related
I have a Google VM, and i can start a web server. The command i issue is: python server.py.
My plan is to have the application running.
Since i will eventually close my pc (and thus the terminal), will the application continue running normally?
Or, do i have to start the server and then use disown, to make the app run in the background?
NOTE: If the second option is the case, does this mean that when i re-log in, and i want to shut down the server, the only way to do it is with pkill?
I'm trying to create a simple Twitter bot to learn some Node.js skills.
It works fine on my local computer. I start the script with node bot.js and then close it with Ctrl + C.
I've uploaded the files to a server (Krystal hosting). I've ssh'd into the server and then used $ source /home/[username]/nodevenv/twitterbot/10/bin/activate. Which I think puts me into a Node environment (I'm not really clear what is happening here).
From here I can run node bot.js. My Twitter bot runs fine and I can leave the terminal. What I've realised now is that I don't know how to stop this script.
Can someone explain how I should be doing this? Is there a command I can enter to stop the original bot.js process? Since looking into this it looks like perhaps I should have used something like pm2 process manager. Is this correct?
Any pointers would be much appreciated.
Thanks,
B
You can kill it externally by nuking the process from an OS command line or in an OS GUI (exact procedure varies by OS). Ctrl-C from the shell is one version of this, but it can be done without the command shell that it was started in too by nuking the process directly.
Or, you can add a control port (a simple little http server running on a port only accessible locally) that accepts commands that let you do all sorts of things with the server such as extract statistics, shut it down, change the configuration, tell it to clear caches so content updates take effect immediately, etc... Shutting down the server this way allows for a more orderly shut-down from code within the server. You can even stop accepting incoming connections, but wait for existing http connections to complete before shutting down, close databases normally, etc...
Or, you can use a monitoring program such as PM2 or forever that in addition to restarting the server automatically if it should ever crash, they also offer commands for shutting it down too (which will just send it certain signals kind of like Ctrl-C does).
I'm developing on the same server where I host some webpages, in this case with Ajenti, nginx and node.js installed on a Ubuntu Server, and I noticed that when I crash the server in a test, I need to log in to ajenti or ssh and restart the webpages.
This made me wonder if nginx or Ubuntu can detect such a crash like a 502 Bad Gateway Error and if there is also a command or tool to restart the webpages?
With this I could probably script it all up and get the webpages restarted, automatically, every time I do something to crash the server.
One solution might be to use something like monit which can (among many other things) check for (and optionally restart) crashed processes.
Sorry about the really ambiguous question, I really have no idea how to word it though hopefully I can give you more detail here.
I am developing a project where a user can log into a website and book a server to run a game for a specific amount of time. When the time is up the server stops running and the players on the server are kicked off. The website part is not a problem, I am doing this in PHP and everything works. It has a calendar system to book a server and can generate config files based on what the user wants.
My question is what should I use to run the specific game server on the linux box with those config files at the correct time? I have got this working with bash scripts and cron, but it seems very un-elegant. It literally uses FTP to connect to the website so it can download all the necessary config files and put them in a folder for that game and time. I was wondering if there was a better way of doing this. Perhaps writing a program in C, but I am not sure how to go about doing this.
(I am not asking for someone to hold my hand and tell me "write this code here", just some ideas of a better way of approaching this problem)
Thanks so much guys!
Edit: The webserver is a totaly different machine. I would theoreticaly like to have more than one game server where each of them "connects" (at the moment FTP) to the webserver, gets a file saying what it has to do at a specific time and downloads any associated files then disconnects.
I think at is better suited for running one time jobs than cron.
For a better approach for the downloading files etc, you should give more details on your setup (like, the website and the game server, are they on the same machine? Or the same network? etc etc.
You need a distributed task scheduler. With that, you can:
Schedule command "X" to be run at a certain time.
Specify the machine (or ask it to pick a machine from a pool of available machines)
Webserver would send request to this scheduler via command line or via web service when user selects a game server and a time.
You can have a look at : http://www.acelet.com/super/SuperWatchdog/index.html
EDIT :
One more option :http://jobscheduler.sourceforge.net/
This may be a basic question, but how do I go about effeciently deploying updates to currently running node.js code?
I'm coming from a PHP, JavaScript (client-side) background, where I can just overwrite files when they need updating and the changes are instantly available on the produciton site.
But in node.js I have to overwrite the existing files, then shut-down and the re-launch the application. Should I be worried by potential downtime in this? To me it seems like a more risky approach than the PHP (scripting) way. Unless I have a server cluster, where I can take down one server at a time for updates.
What kind of strategies are available for this?
In my case it's pretty much:
svn up; monit restart node
This Node server is acting as a comet server with long polling clients, so clients just reconnect like they normally would. The first thing the Node server does is grab the current state info from the database, so everything is running smoothly in no time.
I don't think this is really any riskier than doing an svn up to update a bunch of PHP files. If anything it's a little bit safer. When you're updating a big php project, there's a chance (if it's a high traffic site it's basically a 100% chance) that you could be getting requests over the web server while you're still updating. This means that you would be running updated and out-of-date code in the same request. At least with the Node approach, you can update everything and restart the Node server and know that all your code is up to date.
I wouldn't worry too much about downtime, you should be able to keep this so short that chances are no one will notice (kill the process and re-launch it in a bash script or something if you want to keep it to a fraction of a second).
Of more concern however is that many Node applications keep a lot of state information in memory which you're going to lose when you restart it. For example if you were running a chat application it might not remember who users were talking to or what channels/rooms they were in. Dealing with this is more of a design issue though, and very application specific.
If your node.js application 'can't skip a beat' meaning it is under continuous bombardment of incoming requests, you just simply cant afford that downtime of a quick restart (even with nodemon). I think in some cases you simply want a seamless restart of your node.js apps.
To do this I use naught: https://github.com/superjoe30/naught
Zero downtime deployment for your Node.js server using builtin cluster API
Some of the cloud hosting providers Node.js (like NodeJitsu or Windows Azure) keep both versions of your site on disk on separate directories and just redirect the traffic from one version to the new version once the new version has been fully deployed.
This is usually a built-in feature of Platform as a Service (PaaS) providers. However, if you are managing your servers you'll need to build something to allow for traffic to go from one version to the next once the new one has been fully deployed.
An advantage of this approach is that then rollbacks are easy since the previous version remains on the site intact.