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In this article, the editor introduces in detail "how to use Supervisor to guard the ASP.NET Core application process". The content is detailed, the steps are clear, and the details are handled properly. I hope this article "how to use Supervisor to guard the ASP.NET Core application process" can help you solve your doubts.

I. Preface

At present, there are the following main problems in launching ASP.NET Core applications in a self-hosting way:

The ASP.NET Core application runs in a shell session, and if you close the shell session window, you will find that the ASP.NET Core application will also be closed, making the application inaccessible, which is zero tolerance in a production environment.

If the ASP.NET Core process terminates unexpectedly, you need to connect to the shell to start it again, which is often not timely enough.

If the server is down or needs to be restarted, we still need to manually connect to shell and start the ASP.NET Core program.

In order to solve the above problems, we need a program to monitor the state of the ASP.NET Core application and restart it immediately when the application stops running.

II. Supervisor

Supervisor is such a tool for monitoring the running status of ASP.NET Core applications. It is a client/server service developed with Python. It is a process management tool under the linux/Unix system. It does not support the Windows system. It can change an ordinary command line process into a background deamon and monitor the status of the process. It can easily monitor, start, stop, and restart one or more processes. With Supervisor management process, when a process is accidentally killed, Supervisor monitoring process after the death, will automatically restart the process, it is very convenient to achieve the automatic recovery of the process function, no longer need to write their own shell script to control. Let's take a look at how to install Supervisor on Linux.

1. Install Python package management tools

Install the Python package management tool using the following command:

Yum install python-setuptools

As shown in the following figure:

2. Install Supervisor

Install Supervisor using the following command:

Easy_install supervisor

As shown in the following figure:

3. Configure Supervisor application daemon

Generate the initialization configuration file for supervisor by running the echo_supervisord_conf program, with the following command:

Mkdir / etc/supervisorecho_supervisord_conf > / etc/supervisor/supervisord.conf

As shown in the following figure:

Then we edit the supervisord.conf file and add the following configuration at the end of the file:

; conf.d is the folder of the configuration table directory, so you need to create [include] files = / etc/supervisor/conf.d/*.conf manually.

As shown in the following figure:

Then we manually create a conf.d folder:

Mkdir / etc/supervisor/conf.d

As shown in the following figure:

The directory structure after creation is shown below:

Supervisord.conf is the main configuration file, and the application configuration file is placed under the conf.d folder. Then create a file named AspNetCoreDeployDemo.conf for the application and place it in the directory "/ etc/supervisor/conf.d/" with the contents:

[program:AspNetCoreDeployDemo]; program name, identification command=dotnet AspNetCoreDeployDemo.dll required for terminal control; command running directory=/root/NetCore/FDD/; directory where the command is executed; whether the program automatically restarts stderr_logfile=/var/log/AspNetCoreDeployDemo.err.log when exiting unexpectedly; error log file stdout_logfile=/var/log/AspNetCoreDeployDemo.out.log; output log file environment=ASPNETCORE_ENVIRONMENT=Production; process environment variable user=root User identity stopsignal=INTstartsecs=10 executed by the process; automatic restart interval

Execute the following command to run supervisord to see if it works:

Supervisord-c / etc/supervisor/supervisord.confps-ef | grep AspNetCoreDeployDemo

The effect after success:

Then we visit in the browser:

So you can access it. As you can see, we don't need to start the command line at this time. And you can also get data by closing the shell window.

If the service is already started, modify the configuration file to make it effective with the "supervisorctl reload" command.

4. Configure Supervisor to boot

Let's create a new "supervisord.service" file with the following contents:

# dservice for systemd (CentOS 7.0 +) # by ET-CS (https://github.com/ET-CS)[Unit]Description=Supervisor daemon [service] Type=forkingExecStart=/usr/bin/supervisord-c / etc/supervisor/supervisord.confExecStop=/usr/bin/supervisorctl shutdownExecReload=/usr/bin/supervisorctl reloadKillMode=processRestart=on-failureRestartSec=15s [Install] WantedBy=multi-user.target

Upload the file to the "/ usr/lib/systemd/system/" directory and execute the following command:

Systemctl enable supervisord

As shown in the following figure:

Execute the following command to verify that it is booting:

Systemctl is-enabled supervisord

As shown in the following figure:

At this point, the configuration is complete. We can restart the virtual machine to verify that the application will be started when it is powered on. This has been tested, restart the virtual machine, and then log in with the root user to access the application directly.

We can also use the Web management interface to manage supervisor, in the web management interface, you can restart the process, log view and other operations.

To operate the web interface, you need to add the [inet_http_server] option group to the supervisor configuration file. We use notepad file to open the supervisord.conf file and remove the ";" in front of the [inet_http_server] option group:

Reload the service after modification:

Supervisorctl reload

As shown in the following figure:

Because port 9001 is used, we need to add port 9001 to the firewall:

Firewall-cmd-zone=public-add-port=9001/tcp-permanent

As shown in the following figure

After modifying the firewall, you need to restart the firewall configuration:

Firewall-cmd-reload

Then access url: http://192.168.254.128:9001/ in the browser. If the configuration is normal, you will need to enter the user name and password. Enter the user name and password in the configuration file to log in. After successful login, the interface is as follows:

Here you can see the running process, and you can restart, stop, and so on.

III. Summary

The commands commonly used by Supervisor are as follows:

Supervisorctl restart; restart specified application supervisorctl stop; stop specified application supervisorctl start; start specified application supervisorctl restart all; restart all application supervisorctl stop all; stop all application supervisorctl start all; start all applications

If the following error is reported during the execution of the command:

Error: .ini file does not include supervisorctl section

For help, use / usr/local/bin/supervisorctl-h

As shown in the screenshot:

You need to change to the / etc/supervisor directory to execute the above command.

After reading this, the article "how to use Supervisor to guard the ASP.NET Core application process" has been introduced. If you want to master the knowledge of this article, you still need to practice and use it yourself. If you want to know more about the article, you are welcome to follow the industry information channel.

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