How to deploy and manage applications on Linux systems

In today's IT era, Linux system has become one of the most popular operating systems. Many people in the industry like to use Linux to deploy applications because the Linux system is stable and open source, and developers can easily develop and integrate applications.

This article will introduce how to deploy and manage applications on Linux systems. We will use a real application as a case and demonstrate how to implement deployment and management through specific code examples.

Preparation of the application

Before we start, we need to prepare a simple application and package it into an executable file. We will use a simple Python script that will output "Hello, World!".

The following is a code example for the Python script:

#!/usr/bin/env python3
print('Hello, World!')

Before running this script, we need to ensure that Python 3 is installed. You can check by entering the following command at the command line interface:

python3 --version

If Python 3 has been successfully installed, you should see output similar to the following:

Python 3.8.5

Next, we will use PyInstaller Package Python script into executable file. PyInstaller is a packaging tool for Python applications that packages Python code into independently executable binaries. You can install it through the following command:

pip3 install pyinstaller

After installing PyInstaller, enter the following command to package the Python script:

pyinstaller --onefile hello.py

After running, you should see the packaging in the dist directory hello executable file.

Application Deployment

Now, we can deploy the packaged application to the Linux system. We will use the Debian family of Linux systems (such as Ubuntu) as an example.

First, upload the packaged hello executable file to the Linux system. You can use the scp command to upload files to the remote server:

scp -P <port> /path/to/hello user@server:/path/to/destination

In this command, is the SSH port, /path/to/hello is the path to the packaged executable file, and user is The user name of the Linux system, server is the IP address or domain name of the Linux system, and /path/to/destination is the destination path where you want to place the file.

After uploading the file to the system, we can use the chmod command to set the file as executable:

chmod +x /path/to/hello

Now, we can run the file directly to start the application:

./hello

You should see the output:

Hello, World!

Application Management

Once we have successfully deployed the application, we need to think about how to manage it. Here are some methods for application management:

1. Using systemd

systemd is a basic service manager for modern Linux systems. You can use the systemctl command to start, stop, reload, restart and other services. To configure application services in systemd, you need to create a unit file. Here is a sample hello.service unit file:

[Unit]
Description=hello service

[Service]
WorkingDirectory=/path/to/application
ExecStart=/path/to/hello

[Install]
WantedBy=multi-user.target

You need to save it to the /etc/systemd/system/ directory and start it after systemd reloads:

systemctl daemon-reload
systemctl start hello.service

Of course , you can also use the systemctl command to perform other operations, such as stopping, restarting, reloading, etc.

2. Using supervisor

Supervisor is a tool for managing multiple processes on a Linux server. It allows you to run applications in daemon mode and automatically restart them if they crash. Here is a sample hello.conf file:

[program:hello]
command=/path/to/hello
directory=/path/to/application
autostart=true
autorestart=true
startretries=3
stderr_logfile=/var/log/hello.err.log
stdout_logfile=/var/log/hello.out.log

You need to save it to the /etc/supervisor/conf.d/ directory and reload Supervisor:

systemctl reload supervisor

Now, use supervisorctl Command to start the application:

supervisorctl start hello

Use this command to stop the application:

supervisorctl stop hello

You can also use other commands such as restart, reload, etc.

Conclusion

In this article, we detailed how to deploy and manage applications. We take a Python script as an example, package it into an executable file through PyInstaller, and then deploy it to the Linux system. Subsequently, we discussed some application management methods such as systemd and Supervisor. The above examples all provide code that can be used directly. I hope this article provides you with helpful guidance to ensure you can successfully deploy and manage your application.

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