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Kubernetes for Developers #11: Pod Organization using Labels

Posted by Rama Subba Reddy Mukkamalla on March 29, 2021

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Rama Subba Reddy Mukkamalla: Expert in System Design, Application Architecture, Event-Driven Solutions | AWS Certified Solution Architect | Tech Blogger

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ClosedXML – Read/Write Excel File Using C#.NET

Many of Windows/Web applications having requirement that, get the data from database and import into Excel file. There are several ways for developers to write data into Excel using C#.NET. See the following options 1. Microsoft Excel Interop 2. Microsoft Open XML SDK 3. ClosedXML Microsoft Excel Interop: 1. Office Interop needs Excel driver to be installed on the machine which is generating excel file 2. Excel installed version must match with the interop assembly version 3. Interop calls are expensive in terms of performance Microsoft Open XML SDK: 1. Open XML is developed by Microsoft 2. No need to install Excel driver on the machine 3. It is a document format consists of XML parts stored in ZIP package 4. It is the default format for MS Office 2007/2010 ClosedXML: 1. It is wrapper on Open XML specification 2. No need to install Excel driver on the machine 3. It makes easier for developers to ...

Kubernetes for Developers #1: Kubernetes Architecture and Features

Kubernetes(K8) is an open-source container orchestration tool used for automating deployment, scaling and management of containerized applications. Features: 1. Self-Healing : It restarts container that failed or kills the container that do not respond to container health check endpoint. It always maintains user defined number of replicas 2 . Secret and configuration management : It maintains an application level configuration and secrets in a separate location. So, it can be modified without re-building and deploying container 3. Horizontal scaling: It is easy to scale-up/down containers with a simple command or automatically based on CPU usage. 4. Automatic bin packing: It automatically places containers into the required Worker nodes based on specified CPU/Memory. 5. Storage orchestration : It allows to mount a local storage or cloud providers 6. Automated rollouts and rollbacks: It allows to rollout new application changes by spinning up new container without killing existing conta...

Kubernetes for Developers #8: Kubernetes Object Name, Labels, Selectors and Namespace

Object Name Every Kubernetes object has a Name that is unique for that type of resource within the same namespace. It means, we can only have one Pod name called “ mynginx ” within the same namespace. however, we can use same name for another Kubernetes object like Deployment, Service, etc. So, we can set same name i.e., “ mynginx ” to Pod, Deployment, Service, etc. The following characteristics need to be followed while setting name to Kubernetes object. Name should not exceed 253 characters It contains only lowercase alphanumeric characters (a to z), hyphen (-), period(.) It should start with an alphanumeric character It should end with an alphanumeric character apiVersion : v1 kind : Pod metadata : name : mynginx spec : Labels Label is a key-value pair which is attached to pods, deployments, etc. It acts an identifier on K8 object (Ex: Pod or Deployment). So, the other Kubernetes objects (Ex: Service, DaemonSet) can communicate by matching same ...

Kubernetes for Developers #14: Kubernetes Deployment YAML manifest in-detail

In previous articles, we have learned how to create or manage Pod manually. However, in real-world use cases, The Pod creation/re-creation should be done automatically and remain healthy without manual intervention, that’s where K8 Deployment comes into the picture. It helps us to manage set of identical pods without creating/updating/deleting pods manually. It makes desired number of identical pods always stay up and running automatically without user intervention. It is a high-level resource, the actual pods are created and managed by the ReplicaSets, not by the Deployment directly. ReplicaSet constantly monitors the list of running pods and makes sure the actual number of pods are always matching the desired number of pods. It there are only few pods are running, it creates new replicas from a pod template. If there are many pods are running than desired number, it removes the excess replicas. Deployment YAML file contains both desired replica count and Pod template in it. Therefor...

Knex.js with Azure SQL/MSSQL Server

Knex.js is a SQL query builder for MSSQL, Oracle, MySQL, Postgres and SQLite3. It supports both callbacks as well as a promise interface for streaming data. The following features are supported by knex.js a) SQL Query builder b) Schema builder c) Joins, Groping, Select, Where and etc d) Transactions & Savepoint e) Schema Migrations f) SQL Raw query g) Batch Insert You can find complete details about knex.js @ http://knexjs.org/ Steps to connect to Azure SQL / SQL Server 1. Install Node.js from https://nodejs.org/en/download/ 2. Create folder “Knexmssql” 3. Navigate to folder “knexmssql” Ex: d:\knexmssql > 4. Install following npm modules a) d:\knexmssql > npm install –save express b) d:\knexmssql > npm install –save body-parser c) d:\knexmssql > npm install –save kne...