WEBVTT 00:00.140 --> 00:00.710 Hey, everyone. 00:00.710 --> 00:01.700 And welcome back. 00:01.700 --> 00:06.280 Now in today's video, we will be discussing about the Nginx architecture. 00:06.290 --> 00:12.560 Now, one of the most important things specifically to tune Nginx according to your requirement, is 00:12.560 --> 00:14.690 the Nginx configuration file. 00:14.690 --> 00:19.610 And this is something that you will be playing around with a lot in your production environments. 00:19.610 --> 00:26.900 So Nginx configuration file basically consists of various settings based on which the Nginx will run 00:26.900 --> 00:28.640 and process the request. 00:28.670 --> 00:36.830 Now the primary Nginx configuration file is called as Nginx.conf and it is generally stored in the directory 00:36.830 --> 00:38.360 of Nginx. 00:38.360 --> 00:44.360 Now when we discuss about this directory of etcd, nginx, do note that depending upon the operating 00:44.360 --> 00:47.840 system that you use, this directory might change. 00:47.840 --> 00:55.100 So for example, you have a nginx.conf file here and within here there are two specific configuration 00:55.100 --> 00:56.600 parameters that are defined. 00:56.630 --> 01:02.400 First one is user is equal to nginx and second is log is equal to var log Nginx. 01:02.400 --> 01:05.940 So from the name itself, we can identify what it tries to do. 01:05.970 --> 01:12.720 User is equal to Nginx basically defines the user based on which the Nginx process should run and the 01:12.720 --> 01:18.270 log basically specifies the path where the nginx should store its logs. 01:18.270 --> 01:22.950 So all of these are basically stored in a file called as Nginx.conf. 01:22.950 --> 01:24.990 So let's quickly explore this. 01:24.990 --> 01:30.960 So currently I'm logged in to the server where Nginx is installed and if we'll quickly verify if Nginx 01:30.960 --> 01:37.380 is running or not, let's do a system Ctl status Nginx and as expected, here you see it is active and 01:37.380 --> 01:37.740 running. 01:37.740 --> 01:39.690 I'll press Q to exit. 01:39.720 --> 01:40.320 Great. 01:40.350 --> 01:47.340 Now as we were discussing, the Nginx configuration file is stored in the directory of etcd Nginx. 01:47.580 --> 01:52.050 So if I do an LS over here, you should see Nginx.conf. 01:52.050 --> 01:56.820 Now this is specifically this directory specifically related to RedHat based systems. 01:56.820 --> 01:57.990 For other systems. 01:57.990 --> 02:00.480 It can happen that this path might change. 02:00.480 --> 02:05.250 However, the main important thing is the nginx.conf understanding here. 02:05.250 --> 02:11.880 So let's quickly open up Nginx.conf and let's look into what exactly it contains. 02:11.910 --> 02:16.620 Now, if you look into this file, there are various directives that are available. 02:16.620 --> 02:18.780 First one is user of Nginx. 02:18.780 --> 02:25.230 This is something that we were discussing on how Nginx.conf can contain multiple configuration settings 02:25.230 --> 02:27.300 based on which Nginx will function. 02:27.300 --> 02:34.200 So the first one is user Nginx and along with that there are few more other parameters which we'll be 02:34.200 --> 02:35.700 discussing in just a moment. 02:35.730 --> 02:41.280 Now one important part to remember here, in fact, let me quickly show you so if we'll quickly do a 02:41.310 --> 02:49.830 ps F with hyphen hyphen forest with the grep of nginx over here, you should see that your nginx is 02:49.830 --> 02:55.320 referring to the nginx.conf file which is stored in this specific directory. 02:55.320 --> 03:00.750 So this is also one of the quick ways in case if you are not able to find nginx.conf in a different 03:00.750 --> 03:05.880 operating system, this is one of the ways in which you can identify where your primary configuration 03:05.880 --> 03:06.660 file lies. 03:06.690 --> 03:12.930 Now, one more important thing that you will see over here is that it is showing you that there is a 03:12.930 --> 03:18.210 Nginx master process and there is also a Nginx worker process. 03:18.210 --> 03:21.060 So let's quickly look into what exactly these are. 03:21.090 --> 03:28.020 Now do note that Nginx has one master process and can have one or more worker processes. 03:28.020 --> 03:35.040 So the primary aim of the master process is to read and evaluate the configuration files as well as 03:35.040 --> 03:38.310 maintain the appropriate number of worker processes. 03:38.310 --> 03:43.020 So here you have one master process and there can be multiple worker processes. 03:43.020 --> 03:44.870 And what does the worker process do? 03:44.880 --> 03:51.030 The worker process actually does the processing of requests, whatever requests that is being sent to 03:51.030 --> 03:56.070 your server, The actual processing of requests is something that the worker process does. 03:56.100 --> 04:03.600 Now, when we quickly do a cat on Nginx.conf, the user that you defined over here, you see the user 04:03.600 --> 04:04.620 is Nginx. 04:04.620 --> 04:10.740 So this basically defines what is the user that the Nginx worker process should use. 04:10.740 --> 04:17.220 So if you look into the highlighted area, the master process is running with the root user and the 04:17.220 --> 04:18.500 worker process here. 04:18.510 --> 04:23.940 This worker process is running with the user that is defined within the configuration file. 04:23.940 --> 04:26.340 Very important part to remember here. 04:26.370 --> 04:34.560 Now one more important thing, let's quickly open up the nginx.conf is that in case if you do a mistake 04:34.560 --> 04:38.100 in this specific file, let's intentionally do a mistake. 04:38.130 --> 04:38.700 All right. 04:38.700 --> 04:44.220 So we'll remove this curly braces and I'll save the Nginx configuration file. 04:44.220 --> 04:52.110 Now, at this stage, if we'll quickly do a systemctl status, nginx, you see, Nginx is still working 04:52.110 --> 04:59.520 perfectly well and the primary reason why it is working is because whenever you make change to the nginx 04:59.520 --> 04:59.850 config. 05:00.230 --> 05:00.440 File. 05:00.470 --> 05:02.850 So in this case, this is our configuration file. 05:02.870 --> 05:09.770 Whenever you make changes to this configuration file, this change is not immediately loaded to the 05:09.770 --> 05:11.960 running nginx web server. 05:11.960 --> 05:18.680 So in case if you have made some change in order for that change to come into effect, one of the ways 05:18.680 --> 05:21.090 which you can use is restart Enginex. 05:21.110 --> 05:29.600 So I'll say systemctl, restart nginx and immediately here you see, you got an error over here. 05:29.720 --> 05:37.430 So if we'll quickly do a systemctl status Nginx you see at this moment the nginx has failed. 05:37.430 --> 05:44.450 So that basically means any new request that we send to Nginx that request should also fail. 05:44.450 --> 05:51.200 So if I'll quickly send a request to the IP address of the server where Nginx is running, you see the 05:51.200 --> 05:53.510 request is getting connection refused. 05:53.540 --> 06:00.720 Now within the log you'll also see the exact reason why it is failing, which is stating unexpected 06:00.720 --> 06:03.240 end of file expecting a curly braces. 06:03.240 --> 06:09.210 So this is the curly braces that we had removed in this specific file of nginx nginx.conf. 06:09.210 --> 06:13.020 So let's go ahead and quickly edit the nginx.conf yet again. 06:13.530 --> 06:15.390 We'll add the curly brace. 06:15.390 --> 06:20.370 Let's save this and let's do a systemctl restart nginx. 06:20.400 --> 06:20.940 All right. 06:20.970 --> 06:27.900 Now if we'll quickly do a systemctl status nginx here you should see nginx is up and running and within 06:27.900 --> 06:28.470 the browser. 06:28.470 --> 06:31.020 Also our nginx page is being reflected. 06:31.020 --> 06:34.620 So this is the basics of what nginx.conf is. 06:34.650 --> 06:39.720 Now whenever you're working with Nginx.conf, it is important to be very careful. 06:39.720 --> 06:44.970 Any wrong configuration that you add might affect the production traffic altogether. 06:44.970 --> 06:48.330 So let's quickly open up the Nginx.conf yet again. 06:48.330 --> 06:51.090 We were discussing about the user of Nginx. 06:51.090 --> 06:53.940 The second important part is the worker process. 06:53.940 --> 06:59.400 Now we were already discussing that the worker process actually takes care of handling the requests 06:59.400 --> 07:00.510 that are being received. 07:00.510 --> 07:04.890 And in the worker process here it is mentioned as auto. 07:04.920 --> 07:12.240 Now if you run the PS command yet again, you see that you have one master process and only one worker 07:12.240 --> 07:13.830 process that is available. 07:13.830 --> 07:19.470 So the auto setting that we had specified is only launching one worker process. 07:19.470 --> 07:28.560 Now, in case if you need more worker process here, you can change the setting from auto to two. 07:28.920 --> 07:30.270 We'll save this. 07:30.570 --> 07:37.320 Let's restart our nginx and let's run the PCF command yet again. 07:37.320 --> 07:43.740 And now you see there are two worker processes that are up and running and both of these worker processes 07:43.740 --> 07:48.780 are using the same user that you have specified within the Nginx configuration file. 07:48.960 --> 07:49.560 Great. 07:49.560 --> 07:52.170 Let's open up the Nginx corner again. 07:52.200 --> 07:54.420 The next important part is the error log. 07:54.420 --> 07:58.950 So this basically specifies the path where the error log will be stored. 07:58.950 --> 08:02.130 So the path is var log nginx error dot log. 08:02.130 --> 08:04.080 So let's quickly open this up. 08:04.080 --> 08:13.320 So i'll do ls hyphen l var log nginx error dot log and you should see that we have one file of error 08:13.320 --> 08:14.940 dot log that is available. 08:14.940 --> 08:15.480 Now. 08:15.480 --> 08:25.170 Let's quickly do a less on var log nginx error dot log and one of the log entries that you will see 08:25.200 --> 08:27.570 is the unexpected end of file. 08:27.570 --> 08:31.440 Expecting a curly braces in this specific file over here. 08:31.440 --> 08:34.770 So error dot log is a very important log file. 08:34.770 --> 08:40.200 And specifically this becomes important when your nginx web server is not working at all. 08:40.200 --> 08:47.550 So you will see the appropriate reason why nginx is not really working in this specific error dot log 08:47.550 --> 08:48.030 file. 08:48.060 --> 08:51.480 So let's quickly open up our nginx.conf again. 08:51.480 --> 08:58.200 And the last important directive that we'll be discussing is the PID, which basically contains the 08:58.230 --> 09:03.060 file that has the appropriate process ID, which is why run nginx PID. 09:03.360 --> 09:06.720 So first let's quickly do a CF yet again. 09:06.720 --> 09:10.590 So basically the Nginx process has a specific PID. 09:10.770 --> 09:21.240 Now if you quickly do a cat on Var run nginx PID, it basically contains the process ID which is 30218, 09:21.240 --> 09:26.700 which is basically the process ID associated with the master Enginex process over here. 09:26.730 --> 09:27.480 All right. 09:27.510 --> 09:35.220 Now I hope at this specific stage you understood at a high level overview on the basics of what a Nginx 09:35.220 --> 09:42.390 configuration file is all about and how, depending upon the setting that we need for our production 09:42.390 --> 09:49.140 environment, you can modify various configuration parameters that are part of this nginx.conf file. 09:49.140 --> 09:52.950 So let's quickly revise the important directives that we were looking into. 09:52.950 --> 09:58.530 First one is the user, which basically defines the user credentials which are being used by the worker 09:58.530 --> 09:59.040 process. 09:59.040 --> 09:59.790 Second is the. 09:59.800 --> 10:04.130 A worker underscore processes which defines the number of worker processes. 10:04.150 --> 10:10.000 Now, in this case, setting it to the number of available CPU cores would be a good start. 10:10.000 --> 10:16.270 So in case if you have a CPU cores of two, then to begin with it is important to set the worker process 10:16.270 --> 10:16.810 to two. 10:16.810 --> 10:22.840 Now you also have a value of auto that we were discussing which will try to auto detect it. 10:22.840 --> 10:28.260 So in case if you have one CPU core, it will go ahead and launch one worker process. 10:28.270 --> 10:34.180 The second is error underscore log, which specifies the path to the error log file, and the next is 10:34.180 --> 10:40.030 the PID, which basically defines a file where the process ID of the main nginx process would be stored. 10:40.030 --> 10:44.110 So this is the high level overview about some of the base configuration directives. 10:44.110 --> 10:49.930 In the upcoming video, we'll look into the Nginx configuration file and some of the very interesting 10:49.930 --> 10:52.000 configuration directives in more detail. 10:52.000 --> 10:54.400 So with this, we'll conclude today's video.