Monitoring services and starting them on boot
---------------------------------------------

From wikipedia

> Systemd is a software suite that provides fundamental building blocks for a Linux operating system. It includes the systemd “System and Service Manager”, an init system used to bootstrap user space and manage user processes. systemd aims to unify service configuration and behavior across Linux distributions.

Before going gaga over **systemd** checkout [arguments against](http://without-systemd.org/wiki/index.php/Arguments_against_systemd) it as well. But personally I find it easy to manage. Since I am not well versed in Linux it helps me make less blunders and miss out on doing some things because of lazyness and unfamiliarity. I use a command called **systemctl.** Check if it is supported in your Linux Distro or not.

\# which systemctl  
/bin/systemctl

### Handy Commands

Start an application

    sudo systemctl start application#Examplesudo systemctl start nginx

Stop an application

    sudo systemctl stop application#Examplesudo systemctl stop nginx

Restart an application

    sudo systemctl restart application#Examplesudo systemctl restart nginx

Reload an application

    sudo systemctl reload application#Examplesudo systemctl reload nginx

Check status

    sudo systemctl status application#Examplesudo systemctl status nginx

Example output of status

**●** nginx.service - A high performance web server and a reverse proxy server

Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)

Active: **active (running)** since Wed 2019-01-30 11:29:16 IST; 1 weeks 0 days ago

Docs: man:nginx(8)

Main PID: 909 (nginx)

Tasks: 2 (limit: 1152)

CGroup: /system.slice/nginx.service

├─909 nginx: master process /usr/sbin/nginx -g daemon on; master\_process on;

└─911 nginx: worker process

Jan 30 11:29:15 ubuntu-s-1vcpu-1gb-blr1-01-monitoring systemd\[1\]: Starting A high performance web server and a reverse proxy server...

Jan 30 11:29:16 ubuntu-s-1vcpu-1gb-blr1-01-monitoring systemd\[1\]: nginx.service: Failed to parse PID from file /run/nginx.pid: Invalid argument

Jan 30 11:29:16 ubuntu-s-1vcpu-1gb-blr1-01-monitoring systemd\[1\]: Started A high performance web server and a reverse proxy server.

**Check if active**

If you are using a monitoring service like [zabbix](https://medium.com/@gokulnk/understanding-zabbix-f2a83eeb1221) and need to check if a service is active you can use

\# systemctl is-active nginx

active

### Ready for Restart

Inspite of all the precautions we take there will be scenarios where things fail. As debugging might take more time and can put your application or service out of action, we might be forced to restart our server. Making sure that everything works on a restart is hence very critical.

List all loaded units

systemctl `list-units -all` | grep loaded | awk '{print $1;}'

List all enabled units

systemctl `list-unit-files`| grep enabled | awk '{print $1;}' > enabled.txt

Most of the times we need to make sure that all the services we use are in the start up script.

List all loaded services

systemctl `list-units -all` | grep service | grep loaded | awk '{print $1;}'

List all enabled services

systemctl `list-unit-files` | grep service | grep enabled | awk '{print $1;}' > enabled.txt

To find the list of services which are loaded but not enabled we can do the following.

systemctl `list-units -all` | grep service | grep loaded | awk '{print $1;}' > loaded.txt  
systemctl `list-unit-files` | grep service | grep enabled | awk '{print $1;}' > enabled.txt  
diff -y loaded.txt enabled.txt  
#If you want a quick glance of missing ones you can also use  
diff -y loaded.txt enabled.txt | grep '<'

I know this is not fool proof but it can give you quick glance of missing services.

### Docker, Ansible et al

Making sure that your server works as expected even after restarts lets you sleep with ease at night.

We are considering moving our workflow to Docker and Ansible. That will take some time. Until then we will do with a general setup, hacks like these and a monitoring tool like [Zabbix](https://staging.app.learningpaths.io/#/highlights). Hope it helps you.

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You can read the others articles from the series.

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[**Understanding async-await in Javascript — Gokul N K — Medium**  
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[**Should I use Promises or Async-Await**  
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If you are interested in cryptocurrencies checkout

[**10 things to know/do before investing in cryptocurrencies**  
_“Never Invest In Something You Don’t Understand”_hackernoon.com](https://hackernoon.com/10-things-to-know-do-before-investing-in-cryptocurrencies-a6c72367d854 "https://hackernoon.com/10-things-to-know-do-before-investing-in-cryptocurrencies-a6c72367d854")[](https://hackernoon.com/10-things-to-know-do-before-investing-in-cryptocurrencies-a6c72367d854)

[**Beginner’s Guide to “Investing in Cryptocurrencies”**  
_It has been more than an year since I started investing in cryptocurrencies. Following Warren Buffet’s advice of “Never…_hackernoon.com](https://hackernoon.com/beginners-guide-to-investing-in-cryptocurrencies-e2636d9c2fd9 "https://hackernoon.com/beginners-guide-to-investing-in-cryptocurrencies-e2636d9c2fd9")[](https://hackernoon.com/beginners-guide-to-investing-in-cryptocurrencies-e2636d9c2fd9)

[**Why comparing cryptocurrency prices is wrong**  
_Price is an important indicator. But it can also be misleading in many cases._blog.goodaudience.com](https://blog.goodaudience.com/why-comparing-cryptocurrency-prices-is-wrong-2054a9075878 "https://blog.goodaudience.com/why-comparing-cryptocurrency-prices-is-wrong-2054a9075878")[](https://blog.goodaudience.com/why-comparing-cryptocurrency-prices-is-wrong-2054a9075878)

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