April 30, 2013

Run JVisualVM against another user’s process

Suppose you’re a good admin and you run JBoss as it’s own user rather than as root or yourself, but your devs need to use VisualVM- How do you give them access without providing ssh access to jboss or setting up jstat? Today I figured out I could do this: First, install the required packages to forward X11 traffic: yum install xorg-x11-xauth libXtst Once that’s in place, make sure that you have the following in your server’s sshd_config:

April 12, 2013

Puppet Training Notes from Day 3.

Final notes from day 3: Using an External Node Classifier(ENC) is considered best practice over site.pp There is a “puppet visual index” that has useful examples You can use ~> and -> to chain dependencies to help make things more readable. If I can figure out how to integrate it, I could use LDAP inventory tags to indicate puppet classes Hiera can be used to extract out data from configs Once data is abstracted out, I can put them on github and puppetforge the config_version parameter can be used to control the format of the puppet version (using date command, for example) There is a style guide available for puppet- it’s what puppet-lint uses.

April 11, 2013

Puppet Training Notes from Day 2.

Notes from Day 2: subscribe is the other side of notify the same way require is for before. In puppet.conf, under [agent] set graph=true for previously mentioned dot file creation. I need to take a look at concat, file_line and augeas. Use puppet parser validate init.pp to quick validate syntax. audit=>’content’ will track changes, even if puppet doesn’t care what it is. Setting default values in a class can drastically reduce manifest size.

April 10, 2013

Puppet Training Notes from Day 1.

I am currently in a training class for Puppet, which is a configuration management tool that I use at work. Yesterday was the first day, and here were the things I’ve learned so far: Puppet can actually create a dependency graph to visualize class relationships. By enabling “graph” in one of the configs, it will produce a .dot file for each host showing their dependency tree. Facter can almost single-handedly replace my linux_inventory.

March 8, 2013

LDAP authentication to HTTP Security Realm in JBoss EAP 6

So, you want to tie your jboss EAP 6 management interface into LDAP? Here’s how. This is for EAP 6 in Domain mode tying to an OpenLDAP server, but it should work for Standalone mode as well (I guess, I have no idea for sure). Open up your jboss-eap/domain/configuration/host.xml and Add a new security realm: ``` In the same <management> block as <security-realms>, add ``` and in your management-interfaces, change the realm from ManagementRealm to LDAPRealm: ``` and restart EAP.

March 7, 2013

Quick note on Mod_cluster, JBoss EAP and static content

While trying to configure mod_cluster for a new setup, I ran into a gotcha that got me good- first time I’ve ever seen apache httpd have an out of memory error in my 13 years of using it. The default behavior of mod cluster is to dynamically set up the basic context roots it receives from JBoss -i.e. foo.war has a context of /foo and mod_cluster will forward it without much explicit configuration on the httpd side.

March 2, 2013

Hey, what’s that? Part 10: The Magical

So what else can our locationGenerator describe? How about a magical disturbance. This could be a number of things, from portals to fog to odd smells. During your travels, you stumble across a magical disturbance. You [see/feel/taste/sense/smell/hear] something [strange/unique/powerful]. Ahead of you there is a [colorless/invisible/colorful/red] [portal/cloud/shadow] [floating overhead/ hovering over the ground]. The disturbance fills you with feelings of [uneasiness/joy/revulsion], and yet you find yourself [attracted/repelled] by it.

February 9, 2013

RHCSA? Need a bit’o studyin…

So now that I’m back at an employer that does consulting work, I am re-contemplating getting some certifications simply so I look more valuable on paper. I figure, what the hell, might as well look at an RHCE or RHCSA, so I googled around and found Redhat’s evaluation exam- Here’s the results from the 80 question evaluation: Topic Evaluation Software Management Some Understanding Network Management Unfamiliar Managing SELinux Limited Knowledge NTP Server Configuration Deep Understanding Centralized and Secure Storage Limited Knowledge Web Server Additional Configuration Limited Knowledge Basic SMTP Configuration Deep Understanding Caching-Only DNS Server Deep Understanding File Sharing with NFS Deep Understanding Securing Network Services Deep Understanding Troubleshooting Boot Process Deep Understanding Tuning and Maintaining the Kernel Deep Understanding Enhance User Security Deep Understanding BASH Scripting and Tools Limited Knowledge Network Configuration and Troubleshooting Limited Knowledge Administering Users and Groups Limited Knowledge Manage System Resources Substantial Knowledge Installing and Managing Software Deep Understanding Administer Remote Systems Deep Understanding Deploy and Secure File Sharing Services Deep Understanding Managing SELinux Limited Knowledge Managing Simple Partitions and Filesystems Limited Knowledge Logical Volume Management Deep Understanding Essential Command-Line Operations Deep Understanding Managing Simple Partitions and Filesystems Limited Knowledge Managing Flexible Storage with Logical Volumes Some Understanding Controlling access to Files Substantial Knowledge Installing and Managing Software Limited Knowledge I wish they provided more feedback on what questions I failed- I know that I botched a chunk of the yum, lvm and SELinux questions, but I don’t know which scripting and networking questions I failed.

February 9, 2013

Hey, what’s that? Part 9: The Traveler

Lets look at another type of location generation: the Traveler. There are lots of travelers on the road these days. Perhaps its a traveling merchant, or a dignitary, or a messenger. Perhaps it’s a god or dragon in human form. Maybe a gypsy or a caravan; traveling circus or conmen. Perhaps it’s a mercenary who’s lost returning from a botched job. Maybe its a tax collector with a load of cash.

February 5, 2013

Hey, what’s that? Part 8: The Herd

So what else can our locationGenerator describe? How about cows. Lots of them. A full herd of animals. Technically it doesn’t need to be cows, or even a herd, just a large mass of animals that doesn’t constitute a military unit, which we’ll deal with later. So a herd of cows or buffalo, or it could just as easily be a flock or a pack, gaggle or parliament. Where is the herd?