How to Change Maven Offline Mode

June 30th, 2015 4 comments

Maven is a great tool when it works; otherwise it’s pretty hard to figure out what’s happening and how to fix problems. Instead of detailing steps to get something done, the Maven philosophy is to let developers to pick what they want. For the common use cases that fit in its convention, Maven is pretty easy. In general, Maven is easy to start, and hard to customize.

Categories: Applications & Tools Tags: ,

Installing vCenter Appliance 6.0: A Few Gotchas

June 29th, 2015 2 comments

There is a big change in the vCenter 6.0 with the introduction of Platform Service Controller. To run vCenter 6.0, there must be a PSC server somewhere: either existing one, or new one installed together with vCenter. For most dev/test environments, you would choose the latter option which is also referenced as embedded mode. Because of this separation of vCenter and PSC, the installation process of vCenter appliance 6.0 is quite different from the previous versions.

Setting Up Development Environement for HTML5 and JavaScript

June 28th, 2015 No comments

While JavaScript getting more popular with HTML5 these days, it’s also getting more complicated with various libraries. It’s no longer an easy, if possible, job to manage the dependencies by hands.

As I started to play with JavaScript and HTML5, I have installed several tools for the development. If you’re intested in HTML5, the following steps and links may be helpful to you too.

Simple Script to List and Remove All Stopped Docker Containers

May 27th, 2015 6 comments

While using Docker command lines, I found it’s sometime a bit confusing to deal with containers. For the underlying operating system, a container is like a process. That is why the docker command use “ps” as the command to list these commands.

However, the typical “ps” command lists all the running processes. When a process dies, it is gone and there is no need to list it at all. For the containers, the story is different. The container can also be stopped, paused, which is different from running state. But you can still bring them back to running state later.

How to Pretty Print JSON with Gson and Jackson

May 20th, 2015 No comments

In my last article, I compared two leading JSON APIs in Java: Jackson and Gson. If you have tried the samples there, you may have noticed that the two samples print the JSON string into one line. While it’s pretty efficient for machine, it may not easy for human consumption when the Json string is long. Sometimes I have to copy a long Json string into an editor to find out what are there.

Categories: Software Development Tags: ,

A Little Known Security Feature in vCenter: Certificate Based Authentication

May 18th, 2015 No comments

Although we are all familiar with the username and password based login to the VMware vSphere, it’s also possible to login into vSphere with just certificates. If you are a third party vendor, either IHV (independent hardware vendor) or ISV (independent software vendor), the certificate based login is actually a better and preferred alternative to the one using username and password.

Let me explain why it’s the case, and how it can be done painlessly.

VMware ESXi esxcli Command: A Quick Tutorial

May 12th, 2015 9 comments

The esxcli is a command tool that is available on VMware ESXi for managing ESXi. Unlike the vim-cmd command, it focuses on underlying infrastructure and touches lower level of controls of the ESXi hypervisor itself. Although it’s just one command, it packs a lot of functionalities with different namespaces/sub-namespaces, and sub-commands. Because they are organized in nice tree hierarchy, it’s actually quite easy to use most times.

Categories: Virtualization Tags: ,

How to Enable Remote Management for Docker in VMware Photon

May 11th, 2015 1 comment

It’s an exciting news that VMware got into container business with the release of Photon. The Photon project is not container engine like Docker and Rocket, but more like the CentOS which is a bare minimum version of Linux. The idea is exactly the same as that of the ESXi – the less it does, the more secure a hypervisor or OS is. Sometimes it’s true for people in certain companies and organizations too. :) It’s a culture thing that is beyond this article.

Categories: Cloud Computing Tags: , ,

Announcing vijavaNG 6.0 with vSphere 6.0 Support

May 5th, 2015 4 comments

Even before VMware announced the GA of vSphere 6.0, I’ve started to work on the vijavaNG making sure that vijavaNG will keep up with the latest release of vSphere. Although it may take a bit time for customers and partners to move onto this new release, we want early adopters to have the choice to use the best Java APIs for managing vSphere.

Categories: vSphere API Tags: , ,

Tricks and Tips on Paypal Integration

April 24th, 2015 1 comment

After releasing the DoubleClou ICE, I finally got some time to write what I had experienced with Paypal as a user and developer. Because the DoubleCloud ICE is productivity tool that sells within $100, I want people to buy it online quickly and easily. Given Paypal’s #1 position in online payment, I turned to Paypal without much thinking. After that I had gone through all the integration process from initial research to bring the site to production.

DoubleCloud ICE: the IDE for Managing Clouds

March 30th, 2015 6 comments

After almost one year of intensive development, I am happy to announce the first release of DoubleCloud ICE. It’s an integrated tool for cloud management, in particular VMware vSphere with which you can do a lot of interactions easily and quickly.

The idea was inspired by the IDEs. Once upon a time, we all used editors like vi, Emacs to write code, then compile, link, and debug them using command lines. As time evolved, the IDE came out so we can do all these tasks (actually more) nicely and efficiently in one application. The result? Better user experience and higher productivity.

Gson vs Jackson: Which to Use for JSON in Java

March 27th, 2015 6 comments

There are many JSON libraries for Java. While it’s nice to have many options, it can also be frustrating to decide which one to use. If you do an online search, you will find many opinions and all these libraries are used somewhere. When in doubt, the best thing to do is: stop searching and start coding. It doesn’t take long to get the ultimate answer for you.

Categories: Uncategorized Tags: , , ,

How to Recover Corrupted Virtual Machine in VMware Fusion

March 18th, 2015 4 comments

I just spent quite some time helping a friend to recover a corrupted virtual machine in VMware Fusion. It’s indeed a long and interesting (sometimes frustrating too) process that I learned quite some that I would never otherwise. I think you might find it useful as well. Hopefully, you don’t get a corrupted virtual machine, but in case you do, I am sure the post will help you.

Categories: Uncategorized Tags: , ,

Getting Started with Go Programming Language

February 2nd, 2015 2 comments

Go is a relatively new programming language coming out of Google. It’s getting popular with more new projects using it. Two of the container software, Docker and Rocket are both using Go.

At high level, the Go programming language is very much like C but with many improvements. To my curiosity, I started to study Go and get ready for future consulting projects. Here are the note on installation and a few samples along my learning path.

Ruby Hashie Library

January 28th, 2015 2 comments

Ruby is a very interesting programming language. One powerful feature is its meta programming capability, which allows you to change the programming constructs at run-time. For example, you can change the definition of an existing class from standard library, which could be useful and dangerous at the same time. That is of course a whole other topic.

Categories: Software Development Tags:

Commonly Used Git Commands With Samples

January 27th, 2015 No comments

Git is a powerful version control system. One big differentiator from traditional version control systems is that it’s fully ditributed. In other words, there is no central repository and everyone can have a full clone of everything.

There are many articles and tutorials about GIT already. A while back, I also wrote a few articles on the Java APIs to the JGit implementation. This post is simply a collection of some commands that I use on daily basis. This is just for my quick reference or cheat sheet and nothing more. If you find it’s helpful, it’s great.

Categories: Applications & Tools Tags: ,

Simulating APD Event with ESXi

December 18th, 2014 No comments

APD stands for all path down. It’s a storage issue that is discussed in VMware KB article Intermittent NFS APDs on VMware ESXi 5.5 U1 (2076392). You can install a patch to address the issue with ESXi 5.5.

Categories: Virtualization Tags: ,

Vagrant for Software Development

December 2nd, 2014 1 comment

I came across Vagrant a while back at a bookstore. After browsing it, I didn’t get my hands dirty with it until recently. I started to play with it because one of my clients uses it in setting up development environment for convenience and consistency.

Rotating Log Files with Logback

November 25th, 2014 1 comment

Just fixed an issue related to configuration of Logback recently. You may be wondering why the Logback is used given that it’s much less known than Log4j and Java Logging. Very good question. This page from Logback may provide you some insights. I haven’t tested the performance, but it’s said to be 10 times faster than others. There is also an independent version of comparison on StackOverflow. After browsing it, I didn’t have an impression that I have to use one over the other.

Categories: Software Development Tags: , ,

OAuth For HTTP and REST API Authentication

November 24th, 2014 No comments

Authentication is to verify users are really whom they claim they are. Since its inception, HTTP(s) has used different approaches like BASIC authentication, Form based authentication. Both require passing the user name and password from the client to the server. It’s definitely not good idea to use HTTP because the password is passed as it is or with very limited encoding like BASE64 – very easy to intercept the IP packets and extract out the password. When HTTPs is used, it’s much harder to get the password as all the traffic are encrypted. Still it’s subject to attacks like man-in-the-middle.

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