Deleting Kubernetes namespace issue

Deleting a kubernetes namespace can be done easily with kubectl delete command. However, sometime you would see the deleting process stuck at “Terminating” status and never finish. There is an open issue on Kubernetes Github repository for this issue. It happened to my Kubernetes cluster v1.13 as well.

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Using Traefik as a Kubernetes Ingress Controller

Overview

In Kubernetes (K8s), Ingress is an API object that manages external access to the services in a cluster, typically HTTP. Ingress can provide load balancing, SSL termination and name-based virtual hosting. If you are running web services in K8s, you would need an Ingress service to publish your web content to the internet.

In my previous post, I wrote about how to deploy Kubernetes cluster using kubeadmin. In this port, I am gonna share about using Traefik as an Ingress controller for that deployment.

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Isaac

We had waited for 9 months for today. Our first baby - Isaac has just arrived to the earth :-). Me and my wife are very happy to see him.

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Preparing for the SRE technical interview

It is always fun and interesting to review our knowledges everytime we prepare for a technical interview. As time go, we explore several different new technologies that give us new things to learn and use. We might forget the “basic things” which we use less. In this post, I am gonna list down the fundamental knowledges that we definitely need for the SRE (Site Reliability Engineer) interview. Ah, if you are a DevOps, System Engineer or System Administrator this post is also useful for you :-).

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Deploy Kubernetes cluster using kubeadmin on Ubuntu Server

Kubernetes (k8s) is an open-source system for automating deployment, scaling, and management of containerized applications. Kubernetes is so popular nowadays. There are several ways to deploy and use it. Public cloud services such as Google, Azure, Amazon, etc are offering as well. However if you decide to deploy your own k8s cluster from the beginning, you can use kubeadmin. Let’s discover the steps…

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Manage HPE Smart Array in VMware ESXi 6.7

HPE Smart Array Controller

The HPE Smart Array Controller provides enterprise-class storage performance, increased internal scalability with SAS Expander Card, and data protection for HPE ProLiant rack and tower servers.

There is a built-in tool for managing the Smart Array Controller in HPE Proliant servers. We can access it during the the server boot time to configure the disk arrays. However if we already have ESXi installed on the server and we want to monitor or update the array configuration directly from ESXi’s shell, we can use the offical softwares from HPE.

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How to use NVIDIA graphic card in docker container

What is NVIDIA-Docker?

NVIDIA designed NVIDIA-Docker in 2016 to enable portability in Docker images that leverage NVIDIA GPUs. It allowed driver agnostic CUDA images and provided a Docker command line wrapper that mounted the user mode components of the driver and the GPU device files into the container at launch.

The NVIDIA-Docker overall architecture

The NVIDIA-Docker enables deployment of GPU-accelerated applications across any Linux server. Using Docker, we can develop and prototype GPU applications on a workstation, and then ship and run those applications anywhere that supports GPU containers.

The requirements

Just for your information, the current latest version of NVIDIA-Docker is 2.0. So in this tutorial we will just care about the requirements of this version. In order to run NVIDIA-Docker version 2.0, your Operation System must have:

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Extend VMware virtual machine LVM disk

In order to increase the disk space of an existing virtual machine on VMware ESXi we have to do 2 steps. First, we modify the virtual machine setting to have an addition disk. This is same as we plug a new physical hard disk into a real machine. Second, we will need to go into the OS and modify the disk layout. Let’s see 2 steps in detail.

Adding new disk to the existing VMware virtual machine

Login into VMware ESXi infrastructure using your favorite management tool. You can use the VMware vSphere Client, Web Client or CLI. In this tutorial, i use the VMware vSphere Web Client to add 100GB disk.

Right click on your virtual machine and select Edit settings. Click on Add hard disk and specify the size of new disk.

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Top 5 reasons your crontab scripts are not working

The Crontab

Crontab (cron table) is a configuration file that specifies shell commands to run periodically on a given schedule. It is commonly used to automate system maintenance or administration. Crontab is available in almost Linux distribution and easy to use.

Why crontab scripts are not working?

There are several reasons for that. Following is top 5 reason we might have

1. Crontab software is not installed

Although Crontab is available in almost Linux distribution by default today, there is customized version of Linux that misses cron package. To install cron…

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Improve your code quality with LGTM

What is LGTM?

LGTM (LGTM dot com) is a platform that provides useful insights and code quality information for all sorts of people participating in software development.

  • Use open source libraries and frameworks in private projects and want to know how well they’re being maintained
  • Contribute to open source repositories and want to find out about the quality of the code you contribute
  • Own or administer a public Git repository and want to integrate code quality analysis into your pull request review workflow
  • Want to join the debate on how to define good quality code

Currently LGTM supports to analyze code bases written in C/C++, C#, Java, JavaScript/TypeScript and Python. You can easily integrate LGTM with Github to automate the code analyzing process and review the code quality on each submitted Pull Request before merging.

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