I finished my Chef Recipes and obviously next step is to create and bootstrap VMware virtual machines directly from scripts. I started to test 2 knife plugins knife-esx and knife-vsphere. Quickly I dropped knife-esx solution, because was based on ssh access to the ESX host and we, “the common people”, don’t have rights on that machine. A little bit about my ESX environment: Is an environment with multiple datacenters, multiple clusters, hundreds of virtual machines. On this environment I don’t have full access and requesting one, it takes weeks/months …

In the following article I will try to show you, the power of Ruby in three short hash/array examples.
First I will show you how to sort a key value array by value. Second I will modify the keys name and create another array with this keys (which are already sorted by values).
Third we will sort an array based on the other array keys.

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This is an old bug, first discovered in 2003, but now was applied to the hash table functions from the new programming languages. The main idea behind this bug is to create hashes which collide, because collision will eat a lot more cpu cycles on your server. For a post of 2 MB is resulting in a 44 minutes of CPU time which will results in a DOS.

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Together with some colleagues I started to put the base for a distributed application. Everything is looking good, but we have a big dilemma. We don’t know what communication API to choose. In first phase we didn’t have so many options to choose, but after some research, we found several good communications libraries, and now, is very hard for us to select the best solution.

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I should admit, I didn’t read the Glassfish 3.1 Administration Manual, and I don’t know if this is documented. Anyway the main problem appeared when I tried to connect on my cluster instances with admin credentials. If I connect with VisualVM or JConsole to Domain Administration Server (DAS) on 8686 I don’t have any problem. When I’m trying to connect to my cluster instances on port 28686 with admin credentials I get from JConsole

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I switched all my Java Glassfish webservices to SSL, because I wanted to have an encrypted communication between me and my clients. Until then, all my applications worked flawlessly over the HTTP protocol, but now, after switching to SSL, I got the following error:

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It’s been a while since I configured the latest Dynamic Mass Virtual Hosting Server. Last time I used mod_vhost_alias to create a dynamic virtual hosting and it worked without any problem for what we need in that time. Then we didn’t care about the ftp and virtual users, the sites was updated from web pages and security was pretty much handled by upload application who managed the virtual hosting. Now, the problem is a little bit changed: We need a secure sever which should support ftp virtual users with quota …

Finlay is here. For me, Glassfish 3.1, was one of most awaited piece of software, for all it’s new features and clustering support. Glassfish 3.1 slightly changed the way to install cluster, in a much better and integrated way. This version come with a lot of new functionality, but also with improved parts related to Glassfish 2.1.

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Is not a bug, but a pretty annoying configuration thing which appear when you try to configure Enhanced Broker Cluster in Glassfish. I configured my persistent store, for Enhanced Broker Cluster, as jdbc / MySQL:

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Why you choose SNMP when Glassfish have strong JMX support? I presume, the answer for all who use SNMP is (almost) the same: Because the architecture of current monitoring solution is not scalable enough, and I cannot load my monitoring servers with supplementary JAVA processes.

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