How to choose the port spring-boot-admin will use? - spring-boot-admin

My application has two http port. One for business and the second with actuator. Spring-Boot-Admin chooses the first and it doesn't seem to work, because, I guess, admin need an actuator to work.
How to configure admin to choose right port?

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How do I host my script in a Google Cloud server?

So I have created something small which is a image-rehost where I wish to use Python script where I have a URL such as https://i.imgur.com/VBPNX9p.jpg but with my rehost it would be
https://ip:port/abc123def456
so whenever I access that page it would give me the url that I posted here.
However the issue I am having is that I have no clue how to actually host the server that I made by node-js. Right now I just used the external IP with port of 5000. When I tried to send the image through my home ip by using the
https://external_ip:5000/abc123
the server doesn't recognize anything and nothing is being sent to the server which I in that case think I have setup something wrong.
I am using Google cloud server and I would wish to know how I can host my own server in the google cloud?
As you are having trouble adding a firewall rule, I'm going to suggest make sure port 5000 is open and not 8888.
To open the firewall rule for port 5000 in Google Cloud Platform follow these steps.
1) Navigate to VPC Network > Firewall rules > Create firewall rule.
2) In the 'Create a firewall rule' page, select these settings:
Name - choose a name for this firewall rule
Network - select the name of the network your instance belongs to, most probably
'default' unless you've configured a custom network.
Direction of traffic - 'Ingress'.
Action on match - 'Allow'.
Targets - 'All instances in the network'.
Source filter - 'IP ranges'.
Source IP ranges - '0.0.0.0/0'.
Second source filter - 'None'.
Specified protocols and ports - 'tcp:5000' or 'udp:5000' depending on whether the protocol you are using uses tcp or udp.
3) Hit 'Create'.
This will create a rule allowing traffic on port 5000 to all instances in your network from all IP address sources.
My advice would be to see if these settings work, and then once confirming this, lock down the settings by specifying a specific IP address or range of IP addresses in the 'Source IP ranges' text box, and adding a target tag to you instance and specifying 'Specified target tags' so the port is only open to the instance.
If this doesn't work, you may have a firewall rule turned on within the instance, which you would need to configure (or turn it off).
For more detailed information about setting firewall rules please see here.
For running Node.sj on GCE VM I will suggest you use the Bitnami Node.js package on GCP Marketplace which includes the latest version of Node.js, Apache, Python, and Redis. Using a pre-configured Node.js environment gets you up and running quickly because everything works out of the box. Manually configuring an environment can be a difficult and time-consuming hurdle to developing an application.
Also if you wish to do URL redirection you can use URL map feature provided with Google Cloud HTTP load balancer. This feature allows you to direct traffic to different instances based on the incoming URL. For example, you can send requests for http://www.example.com/audio to one backend service, which contains instances configured to deliver audio files, and requests for http://www.example.com/video to another backend service, which contains instances configured to deliver video files. You find steps to configure and more information here.

How to make local running yii2 CRUD application available online?

I have developed Yii2 CRUD application using models, controllers and views. It is used locally on PC. I wanted the users to use it online.
For eg. I have www.example.com and I wanted to make this yii2 CRUD application available on this site. What are the steps?
Your question is not very specific, therefore you haven't received an answer. I'm assuming you are asking about how to use your local PC as the server for an online site. Otherwise please clarify your question.
You will need to do the following steps:
Point the domain name to the public IP address behind which your local PC is sitting. You can find that by going here: http://whatismyipaddress.com/
In your router you need to set up port forwarding (NAT rules) for port 80 (or 443 if using https) to your computer's local IP address.
Depending on your Apache configuration (or whatever webserver you are using) you need to ensure it serves the right website. This is too broad a subject that I can give you any details here.
Note that you are now opening up your local computer to the Internet and hence you should be aware of the security implications it has.

Is it possible to expose an Owin service?

We have created self-hosted services using OWIN. They are working fine inside the server and we can request and retrieve information using the http://localhost. We use a different port for each service so that we can go and get certain information from http://localhost:8001, other from http://localhost:8015 and so on.
Now, we need to expose the results of one of those self-hosted services to access to it through internet. We'd like to provide a custom address such http://ourpublicinfo.mydomain.com:8001 or using the server ip such http://209.111.145.73:8001.
Is that possible?
How can we implement it?
Our server OS is Windows Server 2012 R2
OWIN Self-Hosted apps can run on a Windows Service, as a Console process and, with if desired, as part of a more robust Host like IIS.
Since you mention your app is running as a service you're probably missing all the GUI goodies IIS provides. In reality however, IIS works on top of http.sys, just as HttpListener does (which is probably what you're using to self-host your app) 1. You just need to do some manual set up yourself:
First of all, you need to make a URL reservation in order to publish on a nonstandard port.
Why would you do that? Quite simply because you're not running under localhost alone anymore on your very own local machine, where you probably are an admin and/or have special privileges/powers.
Since this is a server, and the user used for running the Service might not be an admin (most probably), then you need to give permission to that user to use that URL... and here is where URL reservations come into scene.
You pretty much have to options:
open up the URL to be used by any user:
netsh http add urlacl url=http://209.111.145.73:8001/ user="everyone" listen=yes
or open up the URL to be used by the user(s) running the service, e.g.: NETWORK SERVICE:
netsh http add urlacl url=http://209.111.145.73:8001/ user="NETWORK SERVICE" listen=yes
There is a way to make the reservation for several users too, using sddl, user groups, etc... but I'll not get into it (you can look that up).
Second of all, you need to open up a hall through your firewall (if you don't have one on this day and age, I pity you!)
There are plenty of tutorials on this. You can use a GUI, netsh.exe and what not.
Pretty much all you need to do is make sure you allow incoming connections through that port and that should do the trick.
To make sure the hall is open through and through you can use a tool like http://www.yougetsignal.com/tools/open-ports/ and insert 209.111.145.73 in the Remote Address and 8001 in the Port Number.
If for some reason it shows that the port is closed, even after creating an incoming rule in your firewall for it, then you probably have one or more firewalls in between your server and the outside world.
With those to elements in place you should be able to access your Self-Hosted Service from the outside.
As for accessing your service through an address like http://ourpublicinfo.mydomain.com:8001, you'll need to create a DNS entry somewhere, most likely on your Domain Registrar for mydomain.com, where you could create an A Record for your ourpublicinfo subdomain pointing to 209.111.145.73.
From this point on, you should be able to access your service through direct IP and Port or through the afore mentioned URL.
Best of luck!
Note:
If your service will be access from other domains, you might need to make sure you have CORS (Cross Origen Resourece Sharing) well defined and working on your service too ;)

can the different hosts (not ip) forwarding to the same port externally?

Im just wondering, can 2 or more different external hostname/DNS redirect to multiple local servers but same port?
Let's see, I have 2 DNS internet domain for an example, myserver1.com and myserver2.com, and both I have same A record to my forwarded server IP (e.g: 102.123.123.123). Under my server which only has 102.123.123.123 IP address has 2 application servers but instead of trying to make they work, I use different port for each server applications for an example, serverApp1 listening to 0.0.0.0:2010, serverApp2 listening to 0.0.0.0:2020
My point is, is there any way or how to forward my myserver1.com:2000 to serverApp1 (port 2010), and myserver2.com:2000 to serverApp2 (port 2020) but both myserver1.com and myserver2.com has a same A record?
Im quite sure either it is in iptables or /etc/hosts or BIND issues, but guide me if I missed something. And by the way, the servers and DNS records are accessible from the internet which is the firewalls are configured properly. Thanks.
I don't have much experience in that, but I think you will need a third server/firewall/proxy listening for the incoming host and route it accordingly.
Again, I don't have much experience in that, so I'm not sure if the firewall is able to do that.
I think you can use redirection servers like apache.
In my application we want to access lot of intranet servers from internet. So what we did, we configured a apache with all the mappings in httpd.
So when ever a request to apache comes, it will be redirected appropriately.
For example - I have two servers or hostname in intranet : 1) abc.com:7300/context1
2) xyz.com:8900/context2
We configured a apache with host name abcxyz.com:9000. When a request like
abcxyz.com:9000/context1 comes it will be redirected to abc.com:7300/context1 and when a request like abcxyz.com:9000/context2 comes it will be redirected to xyz.com:8900/context2.
In your case since the requests are going through the single server (102.123.123.123), you can use redirection.
Hope it helps.

why webservers use port 80 for real applications?

Just curious. When developing with Casini development server, one has an infinite number of ports. But, the production servers seem to give a particular importance to port 80.
Has that to do with a technical requirement, a convention, or both? I've checked the web but haven't been able to find a clear response so far.
Thanks for helping.
Many services have specifically-assigned ports This allows users to type, for example http://stackoverflow.com and get the website for SO, without needing to enter a port as well. This isn't a technical requirement; however, using a different port requires the user to know an extra piece of information, which must be entered into the URL every time.
When you connect to a server via TCP/IP you specify particular port you connect to. You do not connect to a server and hope that server guesses which port you would like to talk to.
So in most cases you tell browser to use protocol http, say "http://example.com/" then browser uses default port number assigned to that protocol (http) to connect to server "example.com". In this case port is 80. If for example you specify "https://example.com/" then browser looks for default port for https and then connects to port 443 instead.
So if you do not want to tell to every of your users to specify some non-default port for your service (say "http://example.com:60765/") you better use default one.
BTW there is a way to get port number your service listens to by it's protocol name (by asking a service's host's daemon at port 0) but this method seems to be rarely used (if at all).
See also other answers: default protocol numbers are assigned by IANA
It's a convention: you can use whatever port you feel like. You can look at the evolution of RFCs to see when the convention was official (http://www.faqs.org/rfcs/rfc1700.html)
You can see in the RFC 1060 (http://www.faqs.org/rfcs/rfc1060.html ) that it's the ISO Internet Protocol :)
In a production environment your web server is embedded in a server infrastructure (firewalls, proxies) protecting you against attacks from the internet. In such an environment port 80 is normally open for HTTP traffic. If you use this port there is no need to configure your server infrastructure.