Video conference calls is on the rise during the current lockdown as the Coronavirus emergency is forcing companies to transition to remote work. Even Google and Microsoft are giving away enterprise conferencing tools (for a limited time though). For those who want to use their own solution there are a number of open source alternatives.…
All posts by Oleksii Tykhonov
How to send a Telegram alert message using Go
Here’s a simple example of how to send a message from Go via Telegram: package main import ( “bytes” “fmt” “net/http” “encoding/json” ) func send(text string, bot string, chat_id string) { request_url := “https://api.telegram.org/” + bot + “/sendMessage” client := &http.Client{} values := map[string]string{“text”: text, “chat_id”: chat_id } json_paramaters, _ := json.Marshal(values) req, _:= http.NewRequest(“POST”,…
How to setup free willdcard SSL certificate from LetsEncrypt
We’ll use Centos 7. Run: yum install epel-release && yum install install certbot Or if you already have certbot installed yum update certbot Once done fire (change example.com to your domain): certbot certonly –manual -d *.example.com,example.com –preferred-challenges dns-01 –server https://acme-v02.api.letsencrypt.org/directory A certificate created for *.example.com is not valid for example.com, so you have to add it…
Redis: sort keys by size
There are multiple ways to figure out what take so much memory of your Redis instance. The simplest and quickest way is the following: redis-cli –bigkeys But for some cases it’s not enough. Then you can Redis Memory analyzer (requires Python 3.4). It does provide a lot of useful insights but didn’t help me either.…
Installing RabbitMQ on Ubuntu server
RabbitMQ is a messaging broker. It means it can be used as a transport layer to communicate between some applications by sending and receding messages. Sounds quite simple but actually it’s not that simple and has a lot of features. For instance, unlike some other message broker it supports persistence . RabbitMQ is an Erlang application.…
Sending alerts for PHP fatal errors
If you need to send alerts for PHP errors or some other error messages you can use SEC – simple event correlator. Here’s how you can do that. It’s assumed that you use php-fpm / nginx setup on Centos 6.5, but it should work on Debian/Ubuntu as well. Let’s suppose your PHP log is in…
Ansible: installing pyenv on Centos
In one of our previous post we covered how to install Python 2.7 on Centos using pyenv which is a Python versions management tool. Today we will show how to use ansible to do that for you. (If you are on Ubuntu you might want to check ansible-galaxy-pyenv .) Manual installation process is described here. This is how…
Go: how to install on Centos 6.5
Go is a quite new programming language. It was developed in 2007 by Robert Griesemer, Rob Pike, and Ken Thompson. Although it’s not as mature as C, Python or Java, it has already gained significant popularity in developers community. For instance, Docker is written in Go. It’s also in active use in Dropbox, Canonical and…
Ansible: how to add swap memory on your Linux box
If you are not familiar with ansible, you might want to take a look at our previous post. So here’s a problem. If you have, say, Amazon EC2 instance or Rackspace Cloud server, you might want to add swap memory. You can do do it by running the following commands: sudo dd if=/dev/zero of=/mnt/4GB.swap bs=4096…
Ansible: quick intro
Ansible is a solution for remote server management. It’s pure Python and basically the only thing it requires is SSH connection. Why you might want to start using it? Well.. For starters, it’s very simple. It’s possible to start using it after 10 minutes introduction. It doesn’t require to know anything special. All configuration is plain…