troubleshooting

Bookmarks for 28 mar 2014 through 29 mar 2014

These are my links for 28 mar 2014 through 29 mar 2014:

  • LDAP org chart | bitcube.co.uk – For centralised authentication and authorisation, LDAP is the de-facto standard. Whether in its pure form on Unix or in Active Directory guise on Windows, everyone uses it. What many people don't realise is that you can store all sorts of useful (and not so useful) information in LDAP. One field which can be useful is the "manager" attribute. One of our customers use that and so we've written a small script to graph it using the excellent Graphviz tool. It will probably need customising for specific cases, however we hope that people find it useful nonetheless. If you want to alter the output, do have a look at the record format documentation.
  • Puppet errors explained | bitcube.co.uk – Puppet is a wonderful system automation tool, however the learning curve can be a little steep. We've collected some of the errors messages and "strange" behaviour you may come across together with explanations to help overcome these hurdles and boost adoption of this fabulous tool. If you have any useful errors and explanations, please do send them in and we'll update this article.
  • SCAP: Guide To The Secure Configuration of Red Hat Enterprise Linux 5 – This guide has been created to assist IT professionals, in effectively securing systems with Red Hat Enterprise Linux 5.
  • DNS Load Balancing and Using Multiple Load Balancers in the Cloud – […] Load balancing in general is a complicated process, but there's some secret sauce in managing DNS along with multiple load balancers in the cloud. It requires that you draw from a few different sets of networking and “cloudy” concepts. In this second article in my best practices series (my first post covered how to use credentials within RightScale for storing sensitive or frequently used values), I'll explain how to set up load balancers to build a fault-tolerant, highly available web application in the cloud. Here's what you’ll need: Multiple A records for a host name in the DNS service of your choice Multiple load balancers to protect against failure […]
  • gdnsd – gdnsd is an Authoritative-only DNS server which does geographic (or other sorts of) balancing, redirection, weighting, and service-state-conscious failover at the DNS layer. gdnsd is written in C using libev and pthreads with a focus on high performance, low latency service. It does not offer any form of caching or recursive service, and notably does not support DNSSEC. There's a strong focus on making the code efficient, lean, and resilient. The code has a decent regression testsuite with full branch coverage on the core packet parsing and generation code, and some scripted QA tools for e.g. valgrind validation, clang-analyzer, etc. The geographically-aware features also support the emerging EDNS Client Subnet draft for receiving more-precise network location information from intermediate shared caches.

Bookmarks for 3 mar 2014 through 4 mar 2014

These are my links for 3 mar 2014 through 4 mar 2014:

  • Centos yum 404 repository errors | Natural Order Development – […] Basically yum ran through every single mirror and got nothing but 404 errors. I thought something might have gotten broken with yum or maybe the entire Internet changed overnight to a new repository layout (not likely but it has happened before). Well a simple Google for yum 404 led to some message threads that basically said yum's caches were out of data […]
  • Avoiding reboot: Resetting USB on a Linux machine – Every now and then, some USB device misbehaves badly enough to knock out the entire interface, to the extent that the system doesn’t detect any new USB devices. Or work so well with the existing ones, for that matter. The solution for me until now was to reboot the computer. But hey, I don’t like rebooting Linux!
  • AfterLogic WebMail Lite — free ajax webmail – Fast and easy-to-use webmail front-end for your existing IMAP mail server, Plesk or cPanel

Bookmarks for 30 gen 2014 through 10 feb 2014

These are my links for 30 gen 2014 through 10 feb 2014:

  • Binpress – iOS, Android, Web and Desktop Open-Source Code Marketplace – Binpress brings together companies and developers to build an ecosystem around Open-Source code. Open-Source projects that solve real-world problems, Manually curated and professionally supported.
  • Filtering Apache logs / conditional Logging – This can be very troublesome when trying to access certain web pages. The only way to get through is to make use of conditional logging (it is not the only way to control the contents of the logs) To do this, simply define an environment variable ,according to certain criteria, then request that the server does not write the file type within log when this variable exists
  • TestSSLServer – TestSSLServer is a simple command-line tool which contacts a SSL/TLS server (name and port are given as parameters) and obtains some information from it: Supported versions (among SSL 2.0, SSL 3.0, TLS 1.0, TLS 1.1 and TLS 1.2). Support of Deflate compression (TLS-level compression, not HTTP-level gzip/deflate compression, which this tool does not consider). Supported cipher suites, for each protocol version. Server certificate hash and name.
  • gif2mp4 –
  • lionaneesh/RasPod – A simple music server for Raspberry Pi.

Bookmarks for 24 ott 2013 through 13 nov 2013

These are my links for 24 ott 2013 through 13 nov 2013:

Bookmarks for 21 giu 2013 through 24 giu 2013

These are my links for 21 giu 2013 through 24 giu 2013:

  • Base64 Decode and Encode – Online – Have to deal with Base64 format? Then this site is made for You! Use the super simple online form below to decode or encode Your data. If You're interested about the inner workings of the Base64 format, just read the detailed description at the bottom of the page. Welcome!
  • Simple Base64 Encode & Decode on Mac OSX / Linux with OpenSSL – Drew Morris – Looking for a fast and convenient way to Base64 encode / decode a given string using your Mac or Linux machine? You can do it using the pre-installed OpenSSL package.
  • http://www.ndchost.com/wiki/mail/test-smtp-auth-telnet – Below are instructions on how to test SMTP AUTH against a mail server using Telnet and entering the commands by hand. ( base64 via openssl: http://drewsymo.com/how-to/quick-and-simple-base64-encode-on-mac-osx-terminal/ )
  • Two default routes – Linux has very advanced routing, filtering and traffic shaping options. Here is how to configure a system with two default routes.
  • Getting Started with Puppet – Hello World! | ScriptRock – As there’s a lot of interest out there in the various automation tools on offer I thought I’d do a series of blogs covering getting started on each. In particular I wanted to put them to the test regarding how simple it is to go from zero to “Hello World” *. This way I get to play the truly dumb user (not much of a stretch, I know), which is kinda fun too.

Bookmarks for 9 apr 2013 through 11 apr 2013

These are my links for 9 apr 2013 through 11 apr 2013:

Bookmarks for 29 mar 2013 through 2 apr 2013

These are my links for 29 mar 2013 through 2 apr 2013:

Bookmarks for 16 gen 2013 through 17 gen 2013

These are my links for 16 gen 2013 through 17 gen 2013:

  • Graylog2 – Free open source self-hosted log management and exception tracking – Simple log management
    Graylog2 enables you to unleash the power that lays inside your logs. Use it to run analytics, alerting, monitoring and powerful searches over your whole log base. Need to debug a failing request? Just run a quick filter search to find it and see what errors it produced. Want to see all messages a certain API consumer is consuming in real time? Create streams for every consumer and have them always only one click away.

    Free and open source
    Graylog2 is free and open source. It is licensed under the GNU General Public License v3 (GPLv3) and all source code can be browsed on GitHub. The web interface is using Ruby On Rails, the server is written in Java.

    Used by professionals
    The first version of Graylog2 was released in July 2010. Since then there has been rapid and continuous development and a number of major releases.

  • Centralizzare i log mediante Elasticsearch, Logstash e Kibana – Mia mamma usa Linux! – Uno dei principali problemi che si rilevano in fase di debug delle anomalie relative ad applicazioni è la frammentazione delle informazioni. Tanti log, buona parte dei quali inutili, sono sparsi ovunque nelle macchine interessate all’erogazione di questo o quel servizio.
    Tipicamente quando si tratta di servizi ripartiti su più macchine è sempre necessario aprire diverse console all’interno delle quali, per ciascuna macchina, il (o i) file di log vengono aperti, filtrati stampati e via così, sino ad ottenere una situazione degna di Sherlock Holmes, in cui solo consumati ed abili detective riescono a trovare l’indizio che sfugge ai più.

    Esiste però una via migliore per gestire enormi quantità di log in una forma centralizzata, facilmente ricercabile e che usi un’interfaccia gradevole. Si tratta della combinazione di tre software: Elasticsearch, Logstash e Kibana.

  • Seminario “Evoluzione della virtualizzazione su Linux”: video uno e due – “Introduzione” e “Virtualizzazione” – Mia mamma usa Linux! – Nella giornata del 29 giugno 2012, presso l’hotel Holiday Inn di Rho si è svolto il secondo seminario di miamammausalinux.org, intitolato quest’anno “Evoluzione della virtualizzazione su Linux“.

    Viste le numerose richieste ricevute e rispettando sempre la filosofia alla base del progetto miamammausalinux.org, il video del seminario viene proposto integralmente nelle sue parti, insieme alla documentazione fornita ai partecipanti.

    Ecco le prime due parti.

Bookmarks for 15 gen 2013 through 16 gen 2013

These are my links for 15 gen 2013 through 16 gen 2013:

  • Simplify Advanced Shell Scripting With Ruby | AIX | IBM Systems Magazine | System p, System p5, Power System | Ruby, SSH, shell scripting, Bull Freeware, sysadmin, – IBM Systems Magazine – Ruby is just for experienced programmers. right? False! Originating in the mid-1990s, Ruby is a fantastic language, made popular recently by the Web application framework—Ruby on Rails. It’s a massively flexible and easy language to learn. You can find Ruby for AIX in the AIX Toolbox at the Bull Freeware. The script we’ll be creating will do the following:

     

    * Go through a large list of servers.
    * SSH them and determine whether the server is AIX.
    * If so, it will go through all disks, returning their type.
    * It will do all of this completely in parallel in batch at 25 sub-processes at a time.

  • Recovering a lost partition table with a VMFS volume | vInfrastructure Blog – Vi possono essere diversi motivi che portano alla perdita della tabella delle partizioni o alla sua corruzione. Nel caso di datastore VMFS le possibili cause sono: resignature da un altro sistema (ad esempio il backup server, nel caso funzioni in SAN mode), un errore umano (basta eseguire, su dischi condivisi, da vSphere Client un Datastore / Delete da un ESXi non ancora collegato al vCenter Server), o anche a causa di qualche problema lato storage (mi è capitato proprio questo caso di recente su uno storage entry level)[…]

    (Mi è capitato, ho seguito la kb di vmware e ne sono uscito. Comunque sto sudando ancora adesso…)

  • DataFart – DataFart lets you easily graph data from the command line.

Bookmarks for 28 dic 2012 through 9 gen 2013

These are my links for 28 dic 2012 through 9 gen 2013:

  • PeteNetLive – KB0000741 – HP and Cisco – VLANs and Trunks Confusion! – When I first started in IT, I went and did my Cisco CCNA. So I learned that to connect Cisco switches and pass VLAN traffic between them, I needed to create a 'Trunk' to pass the VLAN traffic. Fast forward a few years, and I now work for an HP reseller. Very early on I came to realise that what HP called a 'trunk' was very different from what I had been taught. Below is an article I did a while ago about setting up HP Trunks.
  • OpenNOP – Open Network Optimization Platform – OpenNOP is an open source Linux based network accelerator. It's designed to optimise network traffic over point-to-point, partially-meshed and full-meshed IP networks.
    The goal of OpenNOP is to increase network performance over low speed network connections such as ISDN, DSL, DS1, frame-relay, VPN and other network circuits. To accomplish this we can use a variety of techniques such as compression, deduplication, caching and protocol spoofing.
    The objectives for OpenNOP are:
    Produce a low cost solution to increase network performance, improve the end user experience and deliver this in a easy to use appliance image.
    Provide a single solution for networks on terrestrial, cellular and satellite systems.
    Facilitate an open framework that can be extended by 3rd party modules to improve specific network traffic.
  • Deon’s World – Understanding and using htop to monitor system resources – Every so often there will be something that slows a system down. There are a few tools that can help to identify which process is the cause of this slow down. One such tool is htop. Htop is an interactive and real time process monitoring application for Linux which will show you your usage per cpu/core, as well as a meaningful text graph of your memory and swap usage.