This is the second day of my participation in Gwen Challenge

Pm2 is mentioned in a post about the background startup process of multiple postures. It is like a big butler, managing and coordinating multiple micro services efficiently. It’s amazing.

This article will move from simple use to microservice management.

So let’s try a Web service to get familiar with it. Then, around a very simple micro service platform, using PM2 to manage, so as to get familiar with and even master the essence of micro service management operation and maintenance! Good book recommendations at the end of the article!

Installation and use

Global installation

View the application process

pm2 ls 
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No services are currently started by the PM2 manager, so an empty list is shown above.

First simple Web application effect

const pid = require('process').pid
const server = require('http').createServer((req,res) = >{
    console.log(new Date() + ' - visiting app')
    res.write("Levin - PM2 DEMO - ProcessId: "+pid)
    res.end()
})
server.listen(8000.() = >{console.log('listening at 8000, pid:',pid)})
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And then it’s all pM2

To stop the process, run the pm2 start simpleweb.js command

View application processes and logs

pm2 ls # check the process
pm2 logs simpleweb Pm2 logs is the first column returned by pm2 ls
pm2 monit # Monitor Displays logs of the current application
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Pm2 ensures application process residency

You can try the kill -9 command to kill the process (along with the process ID displayed in the browser). After refreshing the Web page, the new process ID is printed. At this time, PM2 found that the program hung, automatic recovery.

Here’s a quick look at how PM2 works

Manage a mini micro service platform

Just a quick word about microservices

Product display micro-service platform

The image above shows two microservices

• LevinUIApp Front Desk service: Used to display product inventory data.
• BackendApp back-end product service: Provides product inventory data to the front service but has two worker child processes.

Start the UI service

Pm2 start uI-app /app.js --name uiappCopy the code

Start backend processes

The backend service starts two worker threads (-i) :

The process name is Levinbapp and two worker threads are started to use more CPU to improve efficiency. pm2 start backend-app/app.js --name levinbapp -i 2Copy the code

The result is that there are now two applications.



Here, more workers can be easily expanded horizontally through -i. To play more of the service, readers can try it after reading it.

See the effect and micro service log:

# Thunder committee demo code pM2 MonitCopy the code

pm2 stop levinbapp
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Configure management to start/stop service groups

Use pm2 ecosystem to generate a file.config.js file like the one below. Readers can create a foreground app.js and a background app.js without using the blogger’s code.

module.exports = {
  apps : [{
    name: 'uiapp'.script: './ui-app/app.js'.watch: ['./ui-app'] {},name: 'levinbapp'.script: './backend-app/app.js'.watch: ['./backend-app']}],deploy : {// Use SSH to attach microservices to the production server!
    production : {
      user : 'root'.host : 'alicloudtx'.// Ali cloud host
      ref  : 'origin/master'.repo : 'GIT_REPOSITORY'.path : '/demo/levin-demo-msa'.'pre-deploy-local': ' '.'post-deploy' : 'npm install && pm2 reload ecosystem.config.js --env production'.'pre-setup': ' '}}};Copy the code

To recap: The Apps property configudes service groups that require PM2 management. The Deploy attribute then enables users to directly deploy multiple service clusters to Aliyun using PM2.

Then use: pm2 start file.config.js



Deploy to the cloud, which is not shown here. You can deploy to any cloud platform if SSH is configured.

conclusion

Convenience in development and operation and maintenance

• Seamless access to service management

Almost a miracle for NodeJS applications, PM2 natively supports application management and provides command management to view user applications.

Taking the micro-service platform developed by Springboot as an example, students who develop applications need to introduce SpringCloud and other components to discover services and register in the registry. I have also used the spring family bucket to make micro service platform, and then simplify also have to customize a general SpringBoot Starter, the concept is similar!

• Unified management of log workbench

Especially in microservice environments, multiple services, using PM2 Monit, can easily switch microservice logs in a Monit workbench. Large platforms need to do log search, and it is not practical to switch between hundreds of services in the PM2 Monit window, which is what PM2 lacks!

However, PM2 also has an online version of Keymetics as a monitoring and management platform for professional micro services (for a fee).

• Easier application of elastic expansion

When the background service is started above, a -i parameter is added, and the specified number can start the multi-worker service. While NodeJS is still single-process and multi-threaded, this parameterized instance extension is instructive!

• Encapsulation of service start/restore operations, atomicity

We can use pm2 start/stop appname instead of developing into multiple application directories and manually typing Node app.js. Also, pM2 will live in the application to ensure that the application does not drop, so this design is also worth considering.

For example, the following command:

# remember to add -i 2 otherwise start a worker single thread processing UI request. pm2 start levinbapp -i 2Copy the code

Overall orchestration and deployment configuration management

This paper mainly shows the management operation and maintenance of micro-service application through the use of PM2, pointing out a better direction, so as to guide readers to grasp and optimize the operation and maintenance and management of micro-service platform towards these perspectives!

Take a look at the microservices around you and think about better and more convenient location-based logging, service deployment, start/stop/lateral scaling, etc.?

As for the books

If you want to do microservices, be sure to finish reading this book, Microservices Design.

This is very helpful for the implementation of architecture and operation of micro services, is a classic book in the field of micro services, read more than two times!

Also see the Microservice Platform site at the link for examples.

As an aside, those who are familiar with NodeJS can take a look at its source code, such as service resident/hot load update/seamless access management. These excellent implementations are worth exploring, and can lead to excellent operation and maintenance monitoring platform development.

Code and reference links