Category: Linux

WARNING server login failed: FATAL no pg_hba.conf entry for host “”, user “postgres”, database “postgres”, SSL off

Prabhin Prabharkaran

I have an application that uses Postgres as the database to store application-related data. During my initial setup, I have found the above error in the application while connecting the database. From the above error, we can clearly understand that Postgres is not accepting any connection from 10.244.1.94 IP address. As you know Postgres has host-based access control which accepts the database connection from the listed host. In order to solve this error, we need to add an entry in the pg_hba.conf ( which is the host-based access control file…

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how to get S3 buckets sizes using a cloudwatch

Prabhin Prabharkaran

Get s3 buckets size and cost S3( simple storage Service) is object storage provided by AWS. S3 even helps to host a static website. S3 support to store any kind of data. It’s highly scalable and secure. Security depends all on how the cloud administrator has defined the Access control. If you are a continuous user who pushes your data to the s3 bucket, then you might have noticed the size of the s3 buckets also keeps increasing. So it’s always a better idea to archive the data which are…

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Setup nfs server on Amazon Ec2

Prabhin Prabharkaran

The Network File System (NFS) is a client/server application that lets a computer user view and optionally store and update files on a remote computer as though they were on the user’s own computer. The NFS protocol is one of several distributed file system standards for network-attached storage (NAS). Setup NFS Server In my case, I have a new EBS volume which is mounted to nfs server on location /backup. I need this volume to be mounted on some of the other servers. Step 1: Install NFS-server packages   Step…

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Search and delete files older than “N” days

Praseeb K Das

Lets see how we can  search specific  files or directory which was created “N” days before and delete. For example find files older than 60 days,   Replace the ls with -delete to remove files. Be careful, as you might end up deleting important files.  Always keep backups. Always run -ls option first to check about files. You have been warned. How to ask for confirm before deleting Explanation find : Find command /path/to/dir/ : Directory path to search -type f : Only works on files. (the -type d option…

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Hide Nginx version

Praseeb K Das

By default, the Nginx version will be displayed when we query HTTP headers or error generated by the Nginx server. lets see how we can hide or remove the Nginx version. First lets see how Nginx version is displaying using cli Through curl command,we can see the version on error pages and in the “Server” response header field. Sample Output Now lets hide Nginx Version using server_tokens directive We need to set server_tokens to off to hide the Nginx server version.Now we will edit nginx.conf file.We will set server_tokens in…

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explanation of bind address-from a security point of view

Prabhin Prabharkaran

hi all, this document deals with the explanation of bind address-security. You might have heard about bind-address when configuring certain applications such as Redis, MongoDB, elasticsearch, etc wherein the configuration to choose or configure bind address. Initially, during my starting of my career, I was not knowing what is the use of configuring bind addresses during I do some of the installations. Later going to through hardening servers came to know how important is configuring bind addresses it is. Bind address as the name indicates to which address the service…

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how to use the choice parameter variable in the Jenkins pipeline

Prabhin Prabharkaran

Hi All, this document shows how to use the choice parameter variable in the Jenkins pipeline. Jenkins is a widely used CICD tool that supports a lot of integrations. There are certain use cases to have choice based parameter variables for Jenkins Job. Some cases will be to have true or false variables in other cases you will have options like 1, 2, 3. This allows the user who runs Jenkins’s job will have predefined options as a parameter rather than entering the inputs. One simple use case if you…

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Setup RabbitMQ Cluster on Ubuntu 18.04

Praseeb K Das
RabbitMQ

RabbitMQ is one of the most widely deployed open source message brokers. It is an implementation of the Advanced Message Queuing Protocol (AMQP) and Streaming Text Oriented Messaging Protocol, Message Queueing Telemetry transport and other protocols via a plugin.RabbitMQ is written in the Erlang programming language, it offers support for client interfaces and libraries for all major programming languages including Python, NodeJS, Java, PHP etc. Now let’s see how to set up a RabbitMQ Cluster on Ubuntu Server.   Prerequisites We need three Ubuntu 18.04 servers, let the IP and…

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Find files larger than particular Size in Linux

Praseeb K Das
ind files that are bigger than

We may face disk space issues in our production/development/QA systems were multiple applications will be running. So if we need to search for files greater than the particular size. How would we do that? To check manually each and every file size is particularly difficult. Now we will see how to find files bigger or smaller than X size in Linux systems. Find Files Bigger Or Smaller Than X size We can use “find” command to find the files bigger or smaller than the given size. For now, if we…

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Install Sublime Text on Ubuntu

Praseeb K Das
sublime text editor

Sublime is a popular and widely used text editor that supports multiple programming languages. It is a popular text editor between the developers. It includes wide features such as Syntax Highlight, Auto Indentation, File Type Recognition, Sidebar, Macros, Plug-in and Packages that make it easy for working with the codebase. We can install Sublime through two ways in Ubuntu. Through snapd Through PPA Install Sublime through snapd We can install Sublime-text latest version through below command. After some time it will be installed and sublime will be ready to use.…

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