A Technical I.T./DevOps Blog
Problem scenario
You have a website that is not working. You tried using Fiddler on the front-end. You want to examine the logs on the backend to find the problem. What should you do?
Possible Solution #1
Use a case insensitive grep for “error” or “violation”. Search also for patterns such as “40” and “50” in separate searches.
To get help finding the logs,
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Continue reading “How Do You Search the Logs of a Website that Is Not Functioning Properly?”
Problem scenario
You know .crt and .key files can pair as ssl_certificates and SSL certificate keys respectively. In Nginx, can .pem files replace .crt files? Can .pem files potentially replace .key files? Can a .pem file be a substitute?
Solution
Yes to some extent, for the nginx.conf file, a .pem file can replace a .crt file and potentially a .key file too.
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Continue reading “With Nginx Can a .pem file replace a .crt and/or a .key File?”
Problem scenario
You have Nginx configured. The access logs never pick up any POST message content. You get 405 error messages. What do you do?
Solution
This will send a message payload — but not via POST. It may not work for your situation. To get a message to be sent to a website (a listening web service), craft a URL that does not necessarily exist,
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Continue reading “How Do You Configure Nginx to Listen to Messages Sent via HTTP?”
Problem scenario
The book Expert Python Programming (page 278) says 12 Factor app recommends that the application should not be aware of the format of the logs. JSON format for logs can be beneficial for various purposes. You want Nginx’s access logs — but not error logs — to be in JSON format. What do you do?
Solution
Use a file like this for your nginx.conf.
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Continue reading “How Do You Get Nginx Logs to be in JSON format?”
Problem scenario
You want more verbose log capturing in Nginx. What should you do?
Solution
1. Make a back up of nginx.conf. Then open it. It is often in /etc/nginx/nginx.conf. (Some versions of nginx have a file that does some of the same things called default.conf. This will be the file you will need if you have no nginx.conf file.)
2.
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Continue reading “How Do You Capture More Events in the Nginx Logs?”
Problem scenario
Sometimes you have a web service listening on the loop back IP address on a non-standard port.
When you run nmap -Pn localhost, you see a service is listening on a given port (e.g., 9200). When you run nmap -Pn on an internal or external IP address, you do not see a service listening on that given port. You want to direct traffic to this listening service (e.g.,
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Continue reading “How Do You Make a Web UI Service Accessible to Outside Web Browser Traffic?”
Problem scenario
You have many Docker containers running Nginx. You want to leverage these instances for users to go to one web site and then be automatically routed to different underlying Nginx instances in Docker containers. How do you create a single website for web clients to go to with a reverse proxy balancing the load behind-the-scenes?
Solution
Overview
We accomplish an example with four Docker containers each using a free version of Nginx.
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Problem scenario
You have certain Nginx servers with ample resources whereas others have minimal resources. Based on geographic locations and data center bandwidth locations and costs, you want to assign fractions of the web traffic from client workstations (requests from web browsers) to different Nginx servers more than others. You do not want round-robin, equal distribution of traffic. You want customized HTTP load balancing in accord with unequal configurations. How do you distribute this traffic proportionately according to your desired specifications?
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Problem scenario
You installed Nginx in a Docker container on a RedHat Linux server. You go to this container with a web browser and see the default screen. Where is the default file (on the back-end) that users see from the front-end by default that says “Welcome to nginx!”?
Solution
This is the name and location of the file (assuming the Docker container was created via the public repository):
/usr/share/nginx/html/index.html
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Continue reading “Where Is The “Welcome to Nginx!” Page Stored in a Docker Container?”
Problem scenario
You configured Nginx on a Linux server. You want to see if there has been activity on the website (e.g., via a web browser). What log file, visible on the back-end, has records of web browsing activity?
Solution
It is often here: /var/log/nginx/access.log
For general Nginx purposes, the nginx.conf file specifies the location of the Nginx logs and the names of the log files themselves.
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