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May 7, 2010

» Liveblogging: Senior Skills: Sysadmin Patterns

The Beacon Pattern:
- This is a “Get out of the business” pattern
- Identify an oft-occurring and annoying task
- Automate and document it to the point of being able to hand it off to someone far less technical

- System admins were being put in charge of scheduling rooms in the building
- They wrote a PHP web application to help them automate the task
- They refined the app, documented how to use it, and handed it off to a secretary
- They have to maintain the app, but it’s far less work.

The Community Pattern:

- Prior to launch of a new service, create user documentation for it.
- Point a few early adopters at the documentation and see if they can use the service with minimal support
- Use feedback to improve documentation, and the service
- Upon launch, create a mailing list, forum, IRC channel, or Jabber chat room and ask early adopters to help test it out.
- Upon launch, your early adopters are the community, and they’ll tell new users to use the tools you’ve provided instead of calling you.

- A beowulf cluster for an academic department
- Documented like crazy, early adopters were given early access to the cluster (demand was high)
- Crated a mailing list, early adopters were added to it with their consent, functionality was tested with them.
- Email announcing launch mentioned the early adopters in a ‘thank you’ secion, and linked them to their mailing list.

The DRY pattern
DRY = Don’t repeat yourself
Identify duplicate code in your automation scripts
Put subroutines that exist in an include file, and include them in your scripts.

- “sysadmin library”
- /var/lib/adm/.*pl
- Elapsed time and # of lines to script a task for which the library was useful plunged dramatically
– new tasks were thought up that were not considered before but were obvious now (ie, users that want to change their username)
– migrating to new services became much easier

The Chameleon Pattern
- Identify commonalities among your services
- Leverage those to create “Chameleon” servers that can be re-purposed on the fly
- Abstract as much of this away from the physical hardware
- Doesn’t need to involve virtualization, though it’s awfully handy if you can do it that way.
[this one is a bit harder to do with MySQL config files]

[puppet/cfengine were mentioned...] – more than a script: a methodology

- But isn’t installing packages you don’t need bad? Depends on the package….ie, gcc is bad for enterprise

“Junior annoynances”

Terminal issues

open terminal, login to machine1
think issue is with machine2, talks to machine1.
log out of machine1
log into machine2

opens 2 terminals each of machine1 and machine2 to start

networking issue ticket arrives
logs into server
runs tcpdump

networking issue ticket arrives
logs into server
looks at logs

“Fix” vs. “Solution” ie “taking orders”
Junior will try fix a problem, senior will try to figure out what the problem is. ie, “I need a samba directory mounted under an NFS mount” a junior admin will try to do exactly that, a senior admin will ask “what are you trying to do with that?” because maybe all they need is a symlink.

Signs you might be a fanboy:
- Disparaging users of latest stable release of $THING for not using the nightly (unstable) build which fixes more issues
- Creating false/invalid comparisons based on popular opinion instead of experience/facts
- Going against internal standards, breaking environmental consistency, to use $THING instead of $STANDARD (but this is also how disruptive technology works)
- Being in complete denial that most technology at some point or another stinks.
- Evaluating solutions based on “I like” instead of “we need” and “this does”.

December 3, 2008

Rick Leir
» Implementation patterns

Implementation patterns / Kent Beck, Addison-Wesley, 2008

This book is about design patterns, and the examples are in Java but the concepts apply to many languages. The book is based on the premise that good code matters. In 150 pages, it packs in topics that are vital to a programmer.

Get it from OPL

October 31, 2008

Rick Leir
» Holub on patterns

Holub on patterns : learning design patterns by looking at code / Allen Holub. Apress, 2004

An opinionated look at design patterns. If you are using a language not known for rapid development then you want to choose the right patterns in advance so you won’t be refactoring too much. This book discusses which patterns are most useful, with examples in Java. Not recently written, but worth reading.

Get it from OPL