RedHat / CentOS and getting more proficient

[VinylxScratches]

So in the next year I may have the opportunity to be a Linux Admin that would include an Oracle environment.

The director spoke to me saying they'd think I'd be a good fit.

I have been using Linux at home exculsivly but you know... a production env. is more complex and intense. There are plenty of Linux admins here that I can work with and learn but I'd like to get more of a grasp on RedHat and CentOS.

This is where I struggle though as I'm not sure what I can do. I know a little csh and bash programming. I know how to restart services, check logs and stuff but is there any sources out there that I can use to learn more?

This position is not a promise but I'd like to kickstart my linux skills. I plan on asking if there are any tasks I can take on in the Linux env. at work so we'll see.

 

[ultimatebob]

The best cheap way to brush up on RedHat is to set up a CentOS server at home and try doing things like setting up a web or e-mail server.

If you're willing to spend some cash, however, I'd recommend taking some classes from RedHat and getting your RHCE. Once you have one of those, you'll be more than qualified to be a Linux admin. It would look fantastic on a resume, too.

 

[Paperlantern]

If you are serious about any certs, i'd recommend the guys over at www.techexams.net. They know their stuff and can point you in the direction you need to get just about any cert you are looking for. Could even pose this same question there and see what they say. That site helped me immensely through Security+ and Network+ a while back.

 

[Scarpozzi]

The toughest part about being a linux admin is to make sure you have a good handle on the REAL basics.


Linux Storage
You need to feel comfortable with partitioning, formatting, etc...with and without LVM. (which can cause problems as well as solve them) It takes some trial and error to figure out when to do what and as long as you take your time, you probably won't screw things up too bad. 😛

If your company has a SAN environment, you should get used to the gotchas there. For example, the EMC Powerpath software that some places run on all systems causes problems when you update your system kernel due to incompatibilities with PowerPath and the new kernel versions that Red Hat releases a few times/year. If you don't watch that, you can lose your storage.

Linux Networking
I had similar results with VMware a few years back....running VMware tools, patching the kernel changed something with VMware tools and I lost my virtual NIC. I stopped installing VMware tools on linux hosts and configured NTPD to refresh more frequently to compensate. (Since then, I think those problems have been resolved by VMware...but you never know)

As for the rest of linux networking. Security in linux can be as strong or weak as you make it...so when it comes to iptables...practice opening/closing ports and port ranges, configuring source rules, configuring logging, sendmail, and forwarding root's mail to yourself. It'll give you the logwatch reports nightly so you can see who's banging on your box when you're not watching.

I'm sure taking a linux security class or two couldn't hurt. There are a lot of people who just install linux servers and disable the firewall...don't enforce password policies. I'm not a big fan of SELinux (RHEL/CENT) or AppArmor (SUSE)...but I definitely like the concept.

 

[Khyron320]

I went from Linux enthusiasts to Linux pro by playing with concepts in vms. Setting up a new VM environment for each task and learning. Anytime I completed a setup or a task I copied my bash history to a folder on my desktop. I also cherry pick some commands I came up with and throw them in another list.

Linux admins in a nutshell
We don't restart the server or anything without proof a restart is the only way to fix it.
We tend to have a script for any kind of task
We are very irritated by bad logging practices, or lack of it.

Your post is half a month old any news on how it went?

 

[Scarpozzi]

We are very irritated by bad logging practices, or lack of it.

Wow...that really about sums up my hatred for some products I'm forced to work with. (poorly coded tomcat/java apps that only log at the tomcat layer and don't explain ANYTHING about the root causes of the problems...just the resulting generic compounding java errors)

 

[Khyron320]

That and tomcat is a glass Christmas tree.... 1 bump and it crashes or just stops responding but the pid stays active.