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 :)

Αυγούστου 27, 2009

Work in the future

Κατηγορίες: System Administration — Tags: — Sotiris Tsimbonis @ 12:49 πμ

A few headlines

  • We’ve been describing work as a place we go to for hundreds of years
  • We are still “going to work” today but times are changing
  • Work won’t be a single location anymore
  • Work will be tasks to be accomplished
  • People will be working apart — together
  • Control will be replaced by a culture of trust

If these sound interesting, you should read The remote manager’s toolkit.

Additionally: Marieke Guy’s blog Ramblings of a Remote Worker.

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.

Μαΐου 18, 2009

CDP for linux

Κατηγορίες: System Administration — Tags: — Sotiris Tsimbonis @ 2:18 μμ

Network Inventory .. What a nightmare to keep up-to-date!

Luckily, if you use Cisco switches, CDPR is here to help you discover where do all your network cables end up.. Simply run it on your linux server, wait a few seconds, and your cisco switch will broadcast the info.

Read about it at http://www.debian-administration.org/article/Where_art_thou_-_CDPR.

The opposite is also useful as well..  A daemon run on linux systems that speaks Cisco Discovery Protocol, thus showing up on your switch’s cdp neighborhood ..

I found cdp-send of cdp-tools that works, but ladvd works better with bonding :)

sw-02>show cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
 S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
sw-01            Fas 0/23           150          S I      WS-C3550-1Gig 0/4
router-01        Fas 0/24           158           R       3640      Fas 0/0
linux.local      Fas 0/19           176           H       Linux     eth0

sw-02>show cdp neighbors detail
Device ID: linux.local
Entry address(es):
 IP address: 192.168.1.11
Platform: Linux,  Capabilities: Host
Interface: FastEthernet0/19,  Port ID (outgoing port): eth0
Holdtime : 160 sec

Version :
Linux 2.6.18-92.1.22.el5 #1 SMP Tue Dec 16 11:57:43 EST 2008 x86_64

advertisement version: 2
Duplex: full
Management address(es):

Απριλίου 28, 2009

Send mon alerts to twitter

Κατηγορίες: System Administration — Tags:, — Sotiris Tsimbonis @ 7:55 πμ

Just a quick proof of concept hack..

I modified twitter-cmdline script to fit mon’s alert specs..

Download twitter-cmdline-1.03 and place it in /usr/lib/mon/alert.d (or appropriate path of your mon installation).

Then grab twitter.alert and put it there too.

Run twitter.pl and give your twitter credentials (stored in ~/.twitterrc the first time it runs). It’s probably a good idea to create an extra twitter account for this.

Now use twitter.alert in your mon config to send alerts in twitter, where people can follow them!

watch system01
    service disk_root
        interval 5m
        monitor munin.monitor -M df -F _dev_cciss_c0d0p1 -w 90 -c 95 -H
        depend SELF:ping
        period _ANYTIME_
            alertevery 15m summary
            comp_alerts
            alertafter 3
            alert twitter.alert
            upalert twitter.alert

Απριλίου 22, 2009

Integrating Munin with Mon

Κατηγορίες: System Administration — Tags:, — Sotiris Tsimbonis @ 1:18 πμ

Munin already integrates with Nagios .. But I didn’t find anything for mon ..

So I hacked check_munin.pl from Nagios Exchange to work with mon ..

Download munin.monitor and place it in mon.d/ of your mon installation.

Now you can monitor ANY munin value using mon.

Use something like the following in your systems_monitor.m4

watch system01
    service disk_root
        interval 5m
        monitor munin.monitor -M df -F _dev_cciss_c0d0p1 -w 90 -c 95 -H
        depend SELF:ping
        period _ANYTIME_
            alertevery 15m summary
            comp_alerts
            alertafter 3
            alert mail.alert _MY_EMAIL_
            upalert mail.alert _MY_EMAIL_
    service toomanyqueuedmails
        interval 5m
        monitor munin.monitor -M sendmail_mailqueue -F mails -w 50 -c 100 -H
        depend SELF:ping
        period _ANYTIME_
            alertevery 15m summary
            comp_alerts
            alertafter 3
            alert mail.alert _MY_EMAIL_
            upalert mail.alert _MY_EMAIL_
    service dnsresponse
        interval 5m
        monitor munin.monitor -M dnsresponse_193.92.110.1 -F avg -w 20 -c 50 -H
        depend SELF:ping
        period _ANYTIME_
            alertevery 15m summary
            comp_alerts
            alertafter 3
            alert mail.alert _MY_EMAIL_
            upalert mail.alert _MY_EMAIL_

Make sure that your MON server’s IP is allowed in munin-node.conf of your munin client.

Απριλίου 15, 2009

munin plugin to monitor dns response times

Κατηγορίες: DNS, System Administration — Tags:, — Sotiris Tsimbonis @ 12:00 μμ

A munin plugin that allows you to monitor the response time of any DNS that allows you to recurse.

dnsresponse_ — it’s a poor man’s smokeping DNS probe :)
(wordpress.com does not allow arbitrary file uploads, so grab it from munin-exhange)

To install it, place it in /usr/share/munin/plugins/ and run “munin-node-configure –shell“.

By default it graphs the Average, Median and StdDev of 20 DNS queries.

sample dnsresponse_ graph

sample dnsresponse_ graph

Απριλίου 8, 2009

11ο AutoExec.Gr Community Event στη Θεσσαλονίκη

Κατηγορίες: System Administration — Tags: — Sotiris Tsimbonis @ 7:00 πμ

Το autoexec.gr,  η γνωστή  Ελληνική κοινότητα των IT Pros, οργανώνει συνάντηση στη Θεσσαλονίκη στις 28/04/2009 (στη Μονή Λαζαριστών)..

Φυσικά θα υπάρχουν ενδιαφέρουσες παρουσιάσεις όπως κάθε φορά, και ακόμα πιο ενδιαφέροντα “πηγαδάκια” :)

Οσοι πιστοί προσέλθετε.. http://autoexec.gr/forums/thread/14700.aspx

(Invitation-from:)

Απριλίου 7, 2009

20 of the Best Free Linux Books

Κατηγορίες: System Administration — Tags: — Sotiris Tsimbonis @ 8:37 πμ

LiNUXLiNKS.com has posted a list of their favorite free Linux books.

Individuals wanting to learn about the Linux operating system have a large selection of books to choose from. There are many thousands of informative Linux books which are in-print and available to download or buy at reasonable cost. However, as many users are attracted to Linux for the very reason that it is available under a freely distributable license, some will also want this to extend to the documentation they read. The focus of this article is to select some of the finest Linux books which are available to download for free.

(via)

Απριλίου 3, 2009

date format in en_US locale

Κατηγορίες: System Administration — Sotiris Tsimbonis @ 1:00 μμ

Σίγουρα γίνονται σοβαρές προσπάθιες localization για όλο το περιβάλλον του linux στα Ελληνικά, αλλά καλώς ή κακώς, εγώ προσωπικά πάντα στήνω το σύστημά μου με en_US locale και όχι el_GR.  Ενα θέμα που πάντα μου τη σπάει είναι το date format, που by default είναι month/day/year και όχι day/month/year όπως το περιμένουμε στην Ελλάδα.

Ιδού λοιπόν το 1-line patch για το αρχείο /usr/share/i18n/locales/en_US που διορθώνει το θέμα:

--- en_US.orig  2009-04-03 11:50:02.000000000 +0300
+++ en_US       2009-04-03 11:50:42.000000000 +0300
@@ -107,8 +107,8 @@
 d_t_fmt "<U0025><U0061><U0020><U0025><U0064><U0020><U0025><U0062><U0020><U0025><U0059><U0020><U0025><U0072><U0020><U0025><U005A>"
 %
 % Appropriate date representation (%x)
-%      "%m/%d/%Y"
-d_fmt   "<U0025><U006D><U002F><U0025><U0064><U002F><U0025><U0059>"
+%      "%d/%m/%Y"
+d_fmt   "<U0025><U0064><U002F><U0025><U006D><U002F><U0025><U0059>"
 %
 % Appropriate time representation (%X)
 %      "%r"

Μετά την αλλαγή τρέχουμε locale-gen και είμαστε έτοιμοι :)

Μαρτίου 16, 2009

re: Applications Meme

Κατηγορίες: System Administration — Sotiris Tsimbonis @ 4:26 μμ

I got tagged from kargig, so here are my answers:

  1. Which desktop manager do you use more often ?
    xfce
  2. Which desktop application you would not like to see implemented again on linux? And why?
    Yet another Web browser.. We have enough!
  3. Which desktop application you definitely would like to see implemented on linux? Describe it briefly or point out to a similar application.
    Picasa (linux native, not via wine)
  4. Write the name of the last project (not the very best, the last!) that made you wish to thank their developers so you can thank them now!
    Munin (recently finished a massive deployment on 120 systems), thanks Linpro!
  5. (Optional) Link the blogs of 1-3 people you’d like to take part to this meme. (no more than three). you can skip this question if you like.
    I tag HSOC and v13.

Ιουλίου 22, 2008

Time to disconnect?

Κατηγορίες: System Administration, Uncategorized — Tags: — Sotiris Tsimbonis @ 12:20 πμ

Food for Thought – Time to Disconnect?

Copied from ENISA Quarterly Review Vol. 4, No. 2, Apr-Jun 2008
by Nick Coleman and Pernilla Skantze

It seems widely accepted today that we should regularly check SMS and e-mail on our mobile devices during most meetings. The best situation is when there is wireless broadband access in a meeting room, as we can then do our ‘real’ work (i.e. checking e-mail) while attending the meetings or conferences that for some reason we do not consider demand the same level of attention as e-mail.

Wireless broadband solutions and fixed-mobile functions make it easy to be connected even when we are on vacation, regardless of whether we spend our holidays on a mountain top in the Alps or on a distant beach. When we go for lunch or leave work we can still answer the numerous messages from a person with phone – and we do. Many people say that it takes them several days of vacation to control the urge to check their e-mail. It’s a bit like giving up cigarettes. Only worse…

At the same time, parents all over the world are fighting to tear their children away from their computers or games consoles to go out and play with their friends instead and to do ‘normal’ things that we used to do in the time before all children and teenagers had a computer on their desks.

Or is that really it? In a minor study carried out in the northern outskirts of Europe recently, a number of people were asked to refrain from mobile phone use for a couple of weeks. It turned out that, besides the fact that they had to plan their days much more rigorously, what they missed the most was the alarm clock, the radio function and the fact that they never knew
what time it was.

So the question is, is this healthy? Are we increasingly in an ‘always on’ culture, where we take our Blackberry, mobile phone or laptop with us over the weekend and on holiday as well? Another piece of research suggests taking the laptop on holiday means it may come back with new malware from children accessing sites with new security risks!

So should we all be disconnecting for the summer – throwing away our devices and switching off from work? In the new Sex and the City movie, the main character in the film, Carrie, throws her mobile phone into the sea.

This action of strong emotional distress only happens after she has received numerous messages from a person with whom she has fallen out, and probably many of us have felt the same urge at one control the urge to check their e-mail. It’s point or another. Especially nowadays, when we can’t slam the receiver down in anger any more – pressing “no” doesn’t really have the same effect.

Although many of us still remember a life without mobile devices, was it really any better? Or are all the scares about our dependency on new technology just reactionary, while our lives constantly improve?

And when we go abroad we know transport and hotel rooms can be arranged from a nice bar or beach, without spending time in endless queues. And adding all the other functions we need – camera, clock, wake-up call and music player – our advice to you would be – don’t forget your mobile phone this summer!


Pernilla Skantze (pernilla.skantze@enterprise.ministry.se) is a lawyer specialising in IT-related issues, working for the Swedish Ministry of Enterprise, Energy and Communications, and a member of the ENISA Management Board.

Nick Coleman (nick@n-coleman.com) is the former Head of Security Services for IBM across Europe, the Middle East and Africa, he is currently the Independent Reviewer of information assurance and security to the UK Government and is a member of ENISA’s Permanent Stakeholders’ Group.

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