Vignesh N

linux

Differences in du and df command results

If you find a difference in the outputs of du and df command and want to know how to fix it or how it happened, read this blog.

Amazon web services

Taking snapshot of AWS ElasticSearch

Steps to create a manual snapshot of AWS ElasticSearch

18.04

Setting up L2TP/IPSec VPN in Ubuntu 18.04+

Set up L2TP/IPSec VPN

Amazon web services

Setting up Let's Encrypt on Amazon Linux 2 in AWS

Set up a Let's encrypt certificate on an EC2 instance running Amazon Linux 2 and renew it automatically with AWS Route 53 DNS validation.

email

Send mail from Linux CLI

Follow this blog to send and email from Linux CLI

azure

Uploading SSL certificate to Azure Application gateway

Convert SSL to pfx format and upload it to Azure Application Gateway

Amazon web services

Enable logging in Amazon ElasticSearch - Cloudformation

If you use cloudformation and is facing difficulties while setting up logging in for ElasticSearch, this blog will help you ElasticSearch cloudformationFollowing is a sample cloudformation template for creating ElasticSearch. It is a part of a nested stack and hence some parameter input validation and things like that are missing

azure

Add additional disk in Azure Virtual Machine - No downtime

If you have a virtual machine in Azure which is running out of space, follow the below instruction to add additional disk to the VM. As usual, like all other Azure things, increasing the capacity of a volume is not simple or intuitive like AWS. Increasing the disk space of

Amazon

Need to save some AWS bill quickly? Upgrade to gp3

Procedure for gp2 gp3 upgradation and performance considerations

dd command

Home automation with Home Assistant

If you want a live view of your house using cameras, automatically controlled lights or other appliances with an app or through set rules and a lot of other things that makes your home smart, this is the blog for you. Assumptions Following are the assumptions I am making about

bind mount

Why there was an outage for my site recently - 2

Unlike the previous one, this was not because it was costly. This occurred because I wanted to update WordPress to 5.6. The WordPress 5.6 update is actually fine as is but I’m running this site as a docker with proxy through HTTPD. This for some reason

Finding the max file count in Linux

Introduction There are multiple instances where you’ll need to know the number of files that are kept open by a process, or see those files etc. If you are working on production environments, using commands like lsof or pfile etc will not be possible because you cannot install

elastic search

SSH Tunneling

We have been in situations where we have a server or a service like RDS (Database), Elastic Search, etc. that are in a private network like a VPC (AWS) or a VN (Azure). Putting them as public to access them from the local machine is not secure and it is

application gateway

Add basic auth in Tomcat 8.5

Open tomcat-users.xml with the following command sudo vim /usr/share/tomcat/conf/tomcat-users.xml Enter the following content inside the <tomcat-users> </tomcat-users> tag <role rolename="tomcat"/> <user username="the-user-name" password="th3-p@$$w0rd" roles="tomcat"/> Now open the web.xml file inside your application

AWS

AWS Control Tower

This is where AWS control tower and all its related solutions come together with centrally managed policies, governance and standards with options for account specific or consolidated billing. Introduction Let us consider this scenario. You are a cloud architect/Devops infra person at your organization. You have customers telling you

AMI

NethServer on AWS

If you ever wanted to setup a VPN server, mail server, mail box, web server, or nextcloud (an open source google drive alternative), then you can go through this blog and set it up in minutes using NethServer. NethServer new management web UI at 9090 port Since AWS does not

Amazon web services

Why there was an outage for my site recently

So initially I was running this site in an EC2 instance which costed around 1200Rs. Then I learnt about serverless deployments and made my site serverless about which you can read here. So after going serverless, I was receiving a monthly bill of 2400Rs which was fine since I could

AWS

PC gaming without a rig - using Parsec on Windows!

If you are like me, building a gaming rig would be one of your dreams, but to build a rig that can play high end games on ultra graphics would cost you an arm and a leg. If you are stuck in this situation, then read on to find out

AWS

Setting up a CentOS 8 server as a virtualization host

If you are trying to setup virtual machines in a CentOS 8 server, the following are the steps. I set this up in AWS with an m5d.metal instance (only metal instances allow direct hardware access in AWS. AWS does not support nested virtualization) but it is the same for

centos

MySQL-Cluster group replication

Follow this to setup a MySQL database cluster with group replication. Group replication is where the database across the cluster is constantly synced, so you can write or read from any database and it will be replicated across the other ones. This increases the redundancy and read throughput. Assumptions Following

18.04

NFS server with Lsyncd in Ubuntu

Make the attached volumes ready Create folders sudo mkdir /mnt/upload_disk1sudo mkdir /mnt/upload_disk2sudo mkdir /mnt/backup_disk1sudo mkdir /mnt/backup_disk2 Create partition sudo fdisk /dev/nvme0n1sudo fdisk /dev/nvme1n1sudo fdisk /dev/nvme2n1sudo fdisk /dev/nvme3n1 Make filesystem sudo mkfs.xfs /dev/nvme0n1p1sudo mkfs.xfs /dev/nvme1n1p1sudo

Amazon

Setting up a serverless Wordpress in AWS

First step to setting this up is getting an AWS account. If you already have one, then great!, Otherwise follow the instructions here to create and activate an AWS account. Login to your AWS account First step to setting any resources in AWS is to create a VPC To create