Lab Notes

Things I want to remember how to do.

Development Mail Server (CentOS 8)

November 9, 2020
As you are probably aware, any sufficiently developed software application will eventually grow until it implements email. A frequent stepping stone along that evolutionary path is for an application to gain the ability to send email. If your application sends email, at a certain point it will become inconvenient to continue to use real email addresses and servers when developing and testing the application. The solution is to set up a development mail server.
Read More

Convert Hyper-V disk to KVM

July 11, 2020
When converting a Hyper-V VM to KVM (as used in CentOS or RHEL) it is not enough to simply convert the disk from vhd to qcow2 using `qemu`. Doing so will result in errors concerning `dracut` timing out. Instead one must convert the guest OS as well by using `virt-v2v`.
Read More

Fixing my Borked Ruby Environment

July 2, 2020
So after a couple of updates and who knows what else, I found myself with an environment (Fedora 32 if you were wondering) that would no longer run jekyll. This really caused by blogging level to stop completely since I couldn't preview any of the posts. As the potential posts piled up in my drafts folder, I eventually carved out some time to take care of this.
Read More

JAX-RS Microservices

August 19, 2017
An example project where we have taken a Java library ([java-xirr](https://github.com/RayDeCampo/java-xirr)) and expose it as a REST service using JAX-RS. Then the service is dockerized using the maven dockerfile plugin. On the client side, we create a separate client using the Node.js connect server in order to illustrate various issues with CORS when utilizing REST services.
Read More

Case-insensitive Tag Sorting on GitHub Pages

August 12, 2017
GitHub Pages famously does not support the [`sort_natural`](https://shopify.github.io/liquid/filters/sort_natural/) filter from the [Liquid](https://shopify.github.io/liquid/) templating language used by [Jekyll](https://jekyllrb.com/docs/templates/). So some chicanery is needed to get a list of tags sorted without regard to case.
Read More

Connect to Microsoft VPN from Ubuntu 16.04 Xenial Xerus

August 21, 2016

I recently upgraded from Ubuntu 14.04 on my main desktop machine and discovered that my VPN connection to Windows 2008 Server no longer worked. The bugaboo turned out to be the routing table which no longer requires a gateway entry. Here I have rewritten my post originally written for 12.10 to reflect the new configuration.

Read More

Complicated String Joins

April 4, 2016

So if you have not been under a rock and have used Java 8, you are surely aware of the new String.join() method and the Collectors.joining() method to concatenate arrays or streams of Strings. Sometimes however, a simple concatenation with a delimiter is not quite up to the job.

Read More

jQuery UI Initialization Issues

February 13, 2015
Every once in a while when using jQuery UI I notice that my widget is not being initialized smoothly. For example, when using the menu widget I might see the list items behind the menu briefly. Then the page jumps around and it is a generally unpleasant experience for the user. Who likes it when your jQuery widgets are jumpy and cause the page to feel like one of those old 'punch the monkey' banner ads?
Read More

Liferay 6.2 Portal on JBoss 7.2.0

November 10, 2013

Liferay is a JSR-286 (also known as Portal 2.0) compliant portal (and a whole lot more). Since I am in the market for a portal server for an upcoming project, I figured I needed to check Liferay out. The folks at Liferay have bundled version 6.2 with a number of different open-source application servers, including JBoss 7.1.1, but what fun would it be to simply download a bundle? Liferay is also available as a war download for deployment on existing (and closed-source) application servers. So let’s see if we can get Liferay running on the JBoss 7.2.0 server we built previously.

Read More

Packaging GateIn JavaScript Modules in Separate WARs

November 3, 2013

I have been messing around with the GateIn Portal Server in order to evaluate it for an upcoming project. One nice aspect of the portal is the way JavaScript is handled. JavaScript in GateIn is split into modules and managed via the RequireJS library. This allows the portlet developer to keep their JavaScript isolated and only include the dependencies they require. It also allows for re-use of modules defined in one portlet in other portlets. It doesn’t take a lot of imagination to picture the disaster JavaScript could become on a portal which doesn’t provide isolation and re-use, especially if multiple organizations are providing portals.

Read More

Building GateIn 3.6.3

October 27, 2013

GateIn is a JSR-286 (also known as Portal 2.0) compatible portal based on the JBoss application server (soon to be known as WildFly). The latest version of GateIn with a provided build is GateIn 3.6.0 and is bundled with JBoss 7.1.1. (There is also a beta build of Red Hat JBoss Portal 6.1.0 which bundles GateIn with JBoss EAP and thus carries a more restrictive license.) Note that GateIn is bundled with the application server and is not an add-on to an existing application server.

Read More

Build and Install JBoss 7.2.0 on CentOS 6.4

October 20, 2013

As you may or may not be aware, a great many changes have been happening to the JBoss application server since being purchased by Red Hat. Most importantly, the application server is being rebranded as WildFly for version 8. ("Why?" is the first entry on the WildFly FAQ if you are curious.) But since WildFly is not quite ready as of this writing (but looks real close), we are going to deal with the latest community release, JBoss AS 7.2.0.

Read More

Joining a CentOS server to Active Directory

September 8, 2013

As the number of CentOS (or Red Hat) machines in your environment grows, you begin to appreciate the need for a central login mechanism. Most workplaces already have a such a login for their Windows workstations in the form of an Active Directory domain. By joining your CentOS machines to the Active Directory domain, you allow users to login with the same credentials as on their Windows machines. Furthermore you do not need to add or remove users when new people join the team or others drop off the team.

Read More

Additional AJP connectors within SELinux environment

June 9, 2013

I recently went through the exercise of adding an additional JBoss application server to a production CentOS 6.4 server. The two applications were to be hosted on the same machine using virtual name servers to distinguish requests. I have covered virtual name servers before in my post on install Trac on CentOS 6. Multiple instances of JBoss can be made to play nice on the same servers by shifting the ports via the switch ‑Djboss.service.binding.set=ports‑01.

Read More

Development Mail Server

March 24, 2013

If you have ever needed to develop a web application you have probably needed to send email from the application. Frequently in the applications I work on, we end up using the email address as the login, which means we need lots of email addresses for unit test and integration testing, etc. Using real email addresses for this is not very convenient, so we have used a separate development mail server. Ideally this mail server will accept mail from any development machine, but will not relay mail to any real addresses (so it won’t be an open relay).

Read More

Trac on CentOS 6.3, Part 1

January 20, 2013

Recently I had the need to set up a Trac instance on a 64-bit machine running CentOS 6.3. For CentOS and Red Hat 5, someone has done the hard work already and set up RPM files (see the Trac documentation on RHEL 5 and Dag Wieers RPM repository for details) making installing Trac as easy as yum install trac. Unfortunately, our benefactors have not gotten to RHEL 6 yet so I needed to do it myself.

Read More

Nvidia Overscan in Ubuntu 12.10

January 6, 2013

A few weeks ago I upgraded my HTPC to Ubuntu 12.10 and was treated to a nasty surprise: the overscan settings for the nvidia driver were no longer recognized. The HTPC is connected to my television (naturally) which is a 40" LG LCD HDTV. If you have ever tried to connect your PC to an HDTV before, you probably encountered the problem of that the visible portion of the screen is smaller than the drawable portion of the screen. The result is that the edges of the screen are not visible. In my case that meant the dash and the universal menu of Unity could not be seen. That makes for a less than usable experience.

Read More

Ubuntu 12.10: Connect to Microsoft VPN

December 23, 2012

I recently upgraded to Ubuntu 12.10 on my main desktop machine from scratch, which means a number of things which had been installed and configured need to be re-done. One of those things is my VPN connection to work, which runs Windows 2008 Server for VPN.

Read More

Installing Ubuntu 12.10 on an SSD, Part 3

December 9, 2012

Recently I took the plunge and put an SSD drive into my desktop. Since I needed to re-install the OS, I figured I would install the latest Ubuntu, version 12.10. I went over my trials and tribulations of getting the OS installed in part 1, and dealt with swap in part 2. Today we finish up the tweaks for the SSD.

Read More

Installing Ubuntu 12.10 on an SSD, Part 2

December 5, 2012

Recently I took the plunge and put an SSD drive into my desktop. Since I needed to re-install the OS, I figured I would install the latest Ubuntu, version 12.10. I went over my trials and tribulations of getting the OS installed in part 1, today we are going to talk about some changes I made afterwards to support the SSD.

Read More

An Io Guessing Game

September 30, 2012

So when I get the chance I am working through Bruce Tate’s Seven Languages in Seven Weeks (it might end up being seven years in my case) and commenting on it when the mood strikes. I am currently working through the exercises for Io Day 2 and today I was contemplating the final exercise.

Read More

OS-specific ANT properties

September 26, 2012

The ANT build tool for Java does a pretty decent job of abstracting away OS concerns from your build script. E.g., file paths can always be represented using the / separator and there are tasks for all the typical file system and build operations.

Read More

Io Gotcha

September 22, 2012

As you are probably aware, I am working my way through Seven Languages in Seven Days by Bruce Tate. (And if you have ever googled basic questions on the Io language, you will know that I am not the first person to have this idea.) In any case, I am on Day of Io, but before I get to anything specific there, I wanted to share a gotcha of Io that I encountered.

Read More

Starting Io

September 16, 2012

Well I am back to reading Seven Languages in Seven Days by Bruce Tate and am taking on the chapter on Io. If you are not familiar, Io is a prototype-based language like JavaScript. Since I typically work on the server-side and only dabble in JavaScript and HTML, I am looking forward to seeing how learning Io can reflect on my knowledge of JavaScript.

Read More

Ruby Play List Copier, Take 1

August 2, 2012

So I finally got back to my Ruby play list project. The next mini-goal would be to parse a play list file and print out the converted file names. I created a PlayListEntry class and a PlayList class and things were moving along very well:

Read More

Deleting old files on Windows

July 16, 2012

I ran into a situation today where I wanted to script deletion of folders older than a set number days on an old Windows 2000 machine. (The culprit is a commercial SMTP spam and virus filter that does not clean up after itself when it updates. Eventually the drive gets full and no mail comes through.) I found a solution using forfiles but this version of Windows does not have it. I found myself searching the web and gnashing my teeth over the limitations of Windows batch scripting.

Read More

Welcome

July 14, 2012
I created this blog for two purposes.  First, to capture any random notes on problems I have encountered (and hopefully solved).  Hopefully next time it happens, I'll remember the blog post or Google will remember it for me.
Read More