Don't fear the penguin

Ιανουαρίου 29, 2010

Free Linux Journal Issue 02/2010

Κατηγορίες: System Administration, favorite tools — Tags: — Sotiris Tsimbonis @ 9:44 μμ

Είμαι συνδρομητής του Linux Journal για περίπου 10 χρόνια.. Τα τελευταία δύο, εκτός από την παραδοσιακή έντυπη έκδοση πήρα και το Digital Subscription σε PDF. Μαζί με το Linux Journal Archive CD η συλλογή μου πλέον είναι πλήρης..

Τώρα μου έμειναν ένα σωρό hard-copies του LJ που πιάνουν χώρο.. ή θα τα δώσω σε κάποιο τοπικό εργαστήριο Linux Users Group (thelug?) ή θα τα ανακυκλώσω..

Αυτό το μήνα πάντως, προσφέρουν εντελώς δωρεάν το τεύχος του Φεβρουαρίου 2010 σε PDF..

Κατεβάστε το feb2010-special.pdf και καλη ανάγνωση!

UPDATE: Πάρτε και μια γεύση του επόμενου τεύχους LJ (System Administration): http://ow.ly/16sdFz

UPDATE2: Ο @boukouvalas επικοινώνησε μαζί μου για τα hard-copies στο εργαστήριο του thelug :)

Ιουλίου 30, 2009

dnstop: stay on top of your DNS traffic

Κατηγορίες: DNS, favorite tools — Tags: — Sotiris Tsimbonis @ 9:09 πμ

dnstop is a small utility that displays various tables of DNS traffic on your network. Currently it displays tables of:

  • Source IP addresses
  • Destination IP addresses
  • Query types
  • Response codes
  • Opcodes
  • Top level domains
  • Second level domains
  • Third level domains
  • etc…

Very useful to troubleshoot DNS attacks or generate realtime DNS statistics.

Ιουνίου 24, 2009

RANCID – the Really Awesome New Cisco confIg Differ

Κατηγορίες: favorite tools, network — Tags:, — Sotiris Tsimbonis @ 10:04 πμ

Do you want to backup all your router configurations in one location? Keep them under revision control? Also include their hardware specs, modules etc? grep for serial numbers or configuration directives in all of them? Execute a series of command in some of them? Generate graphs of your network topology automagically? Run security audits on your configs? See what changed last night by other co-workers?

Meet RANCID, the Really Awesome New Cisco confIg Differ, by Shrubbery Networks!

RANCID monitors a router’s (or more generally a device’s) configuration, including software and hardware (cards, serial numbers, etc) and uses CVS or Subversion to maintain history of changes.

RANCID does this by the very simple process summarized here:

  • login to each device in the router table (router.db),
  • run various commands to get the information that will be saved,
  • cook the output; re-format, remove oscillating or incrementing data,
  • email any differences from the previous collection to a mail list,
  • and finally commit those changes to the revision control system

Rancid currently supports Cisco routers, Catalyst switches, Juniper routers, F5 devices, HP Procurve switches and a host of others.

Using a tool like ViewVC, WebSVN or chora to put your repository on the web is a must.

A possible alternative is ZipTie, nowadays known as NetworkAuthority Inventory by AlterPoint.

Ιουνίου 23, 2009

Munin – performance monitoring tool

Κατηγορίες: System Administration, favorite tools — Tags:, — Sotiris Tsimbonis @ 9:49 πμ

My favorite performance monitoring tool: Munin by linpro.

Munin monitoring tool surveys all your computers and remembers what it saw. It presents all the information in graphs through a web interface. Its emphasis is on plug and play capabilities. After completing a installation a high number of monitoring plugins will be playing with no more effort.

Using Munin you can easily monitor the performance of your computers, networks, SANs, applications, weather measurements and whatever comes to mind. It makes it easy to determine “what’s different today” when a performance problem crops up. It makes it easy to see how you’re doing capacity-wise on any resources.

Munin uses the excellent RRDTool and the framework is written in Perl, while plugins may be written in any language. Munin has a master/node architecture in which the master connects to all the nodes at regular intervals and asks them for data. It then stores the data in RRD files, and (if needed) updates the graphs. One of the main goals has been ease of creating new plugins (graphs).

Previous articles in my blog about munin:

Ιουνίου 22, 2009

mtr: Matt’s traceroute

Κατηγορίες: System Administration, favorite tools — Tags:, — Sotiris Tsimbonis @ 10:49 πμ

Another favorite tool.. mtr by Matt Kimball.

mtr combines the functionality of the ‘traceroute’ and ‘ping’ programs in a single network diagnostic tool.As mtr starts, it investigates the network connection between the host mtr runs on and a user-specified destination host. After it determines the address of each network hop between the machines, it sends a sequence ICMP ECHO requests to each one to determine the quality of the link to each machine. As it does this, it prints running statistics about each machine.

Ιουνίου 19, 2009

Dstat: Versatile resource statistics tool

Κατηγορίες: System Administration, favorite tools — Tags:, — Sotiris Tsimbonis @ 10:05 πμ

Meet Dstat, the Versatile resource statistics tool by Dag Wieers.

Dstat is a versatile replacement for vmstat, iostat, netstat, nfsstat and ifstat. Dstat overcomes some of their limitations and adds some extra features, more counters and flexibility. Dstat is handy for monitoring systems during performance tuning tests, benchmarks or troubleshooting.

Dstat allows you to view all of your system resources instantly, you can eg. compare disk usage in combination with interrupts from your IDE controller, or compare the network bandwidth numbers directly with the disk throughput (in the same interval).

Dstat gives you detailed selective information in columns and clearly indicates in what magnitude and unit the output is displayed. Less confusion, less mistakes.Dstat is unique in letting you aggregate block device throughput for a certain diskset or networkset, ie. you can see the throughput for all the block devices that make up a single filesystem or storage system.

Ιουνίου 18, 2009

Dconf: System config collector

Κατηγορίες: System Administration, favorite tools — Tags:, — Sotiris Tsimbonis @ 4:24 μμ
Recommended tool for any linux distro: Dconf by Dag Wieers.
Dconf is a tool to collect a system’s hardware and software configuration. It allows to take your system configuration with you or compare systems (like nodes in a cluster) to troubleshoot HW or SW problems.

Dconf is also useful in projects where you have to manage changes as a team. Dconf can send out changes to your systems to a list of email addresses so that they can be revised.

As a sysadmin, you won’t become too paranoid if less experienced people have root-access. As a consultant, you won’t feel isolated if you don’t have remote access to your systems. As a support engineer, you won’t become frustrated if a customer has fiddled around with some important config file and you have to find what.

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