Connection timeout while connecting to EC2 instance(SSH) after enabling nginx - nginx

Everything was working fine. I could connect to my EC2 instance through SSH. Then I wanted to install let-encrypt. I was following this tutorial to install https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-16-04. During the process of installing lets-encrypt, I install nginx and while trying to enable nginx, I got a message that I might not be able to connect to my instance through SSH anymore. I ignored the message. Now when I try to connect to my instance though SSH, I get error
connection timed out

Related

Node js Application running on EC2 but not accessible in browser using Nginx

I'm a newbie to Nginx. I cannot access my Node.js application that I deploy on AWS EC2 using Nginx reverse proxy. If I do curl http://localhost:3000 I can see the application is running successfully on the server(I'm using pm2 for running node server). But when I try to access it in my browser or postman using public DNS I get the error This site can't be reached and the request gets timeout. Here's my Nginx configuration (I have followed a number of tutorials for this)
The configuration file is named nginx.conf and is in /etc/nginx/sites-enabled directory. If I do sudo nginx -t it says syntax is ok and the test is successful. Also I can see the Nginx is running using command sudo systemctl status nginx What could be the possible reason for this behaviour?
I figured it out the problem wasn't with the Nginx configuration actually I needed to allow public access for port 80 on my ec2 instance which is blocked by default. I allowed port 80 and everything is working fine. This blog helped me. Visit it for me details on how to enable port 80 for your ec2 instance.

What is NGINX [notice] signal process started error message

With regards to nginx error log, what does 2020/10/23 06:51:45 [notice] 361#361: signal process started mean?
Some more context:
I have some raspberry pi's communicating with my Django application on a digital ocean Ubuntu droplet running nginx as the web server. These raspberry pi's stopped communicating with my server and they are physically very far from me. I can see their last communication with my server was at 2020/10/23 06:51:41 then they stopped (seconds before nginx error message was logged).
A user that has access to the pi's said they did not lose power, internet is working, so they did a reboot, still nothing.
I have tried:
sudo systemctl restart nginx followed by sudo systemctl restart gunicorn
This did not resolve the issue. I can't seem to find the documentation on this error
Have you verified the security group of your instance from digital ocean ? I think your port is not opened for http and HTTPS. Cross check for port 80 and 443. Is it opened or closed.

Creating docker repo in Artifactory with dedicated port, it says "SocketException: Permission denied"

I am running Artifactory Pro (5.3.1), and was trying to use the docker registry functionality.
I created a docker repository, and gave it a port 5001 in the "Registry Port" config.
However, there's nothing running on port 5001 ("telnet localhost 5001" refuses to connect), and the logs show this:
[http-nio-8081-exec-7] [ERROR] (o.a.s.s.SshAuthServiceImpl:210) - Failed to start SSH server
java.net.SocketException: Permission denied
at sun.nio.ch.Net.bind0(Native Method) ~[na:1.8.0_72-internal]
at sun.nio.ch.Net.bind(Net.java:433) ~[na:1.8.0_72-internal]
at sun.nio.ch.Net.bind(Net.java:425) ~[na:1.8.0_72-internal]
at sun.nio.ch.AsynchronousServerSocketChannelImpl.bind(AsynchronousServerSocketChannelImpl.java:162) ~[na:1.8.0_72-internal]
at org.apache.sshd.common.io.nio2.Nio2Acceptor.bind(Nio2Acceptor.java:66) ~[sshd-core-0.14.0.jar:0.14.0]
Any idea what could cause a "permission denied"? There's nothing running on that port (same error for any other port). It's on Ubuntu 14.04.
I had a misunderstanding how the docker registry worked with Artifactory.
The Artifactory service doesn't actually open the port assigned to the repo (5001 in this case), but the reverse proxy will listen on it and forward it (with the right X-forwarded-port) to the "normal" Artifactory service port (e.g. 8081).
After setting up the reverse proxy for it, it worked fine.

RServe Connection Issue

need help with setting up connection from Tableau to a server where R is installed. Installed R and Rserve in linux.Started the Rserve from R console using
library(Rserve)
Rserve()
In Tableau trying to set up connection and then test connection by providing Server name and port as 6311 I get below error
"Connected party did not properly responded after a period of time, or
established connection failed because connected host has failed to
respond"
tried chkconfig iptables off and service iptables stop but no use.

why i am getting this error "Installation failed. Failed to receive heartbeat from agent." in cloudera installtion

I am installing cloudera manager on local machine.
When trying to add new host getting following error
Installation failed. Failed to receive heartbeat from agent.
Ensure that the host's hostname is configured properly.
Ensure that port 7182 is accessible on the Cloudera Manager server
(check firewall rules).
Ensure that ports 9000 and 9001 are free on the host being added.
Check agent logs in /var/log/cloudera-scm-agent/ on the host being
added
(some of the logs can be found in the installation details).
i checked the logs,it shows like hostname differs from canonical name
So I also changed the hostname from /etc/resolv.conf
But still getting sam error
I had the same error for a simple mistake in the file /etc/hosts :
Have you checked you have DNS and reverse DNS ?
Then to check if your port is open 7182, you should do a telnet IP 7182 (replace IP by the host of Cloudera Manager Server).
If there are still some problems, maybe you have forgotten to deactivate the firewall (iptables).
Regards, K.
To resolve this issue you need to check first all port opened on your server service listing to the port no, use command: sudo netstat -lpten
Check if any thing is running on 9000 or 90001, mostly java services required for set up is running on port 9000, and cloudera-scm-agent listner also runs on port 9000. to over come this issue you can re-configure theports as well in /etc/cloudera-scm-agent/config.ini by changing as below:
--------------------------------------------------
## It should not normally be necessary to modify these.
# Port that the CM agent should listen on.
listening_port=9001
-------------------------------------------------
and then restart the cloudera-scm-agent service by command:
service cloudera-scm-agent restart
To verify this port is not activated for other sshd service check Ports opened in /etc/ssh/sshd_config.
I hope this resolution will work for others too.
Cheers,
Ankit Gupta

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