1. MySQL 1 - Installation and basic concepts


    The installation of MySQL is straighforward on debian-like systems. Just type:

    sudo aptitude install mysql-server mysql-client -y

    In the installation process you'll be asked to set up the password for the admin user. Remember this password because you'll need it in a moment. One thing, though, this username must NOT be used by your applications because it has ALL privileges possible, and you don't want your application to have the right to drop other databases installed in the same MySQL. Limited users must be created for ...

  2. A few notes about the MongoDB course

    Two weeks ago I took a three day MongoDB course at CAPSiDE. Really interesting. If you are planning to use this technology I strongly recommend you to take one of this courses, if you can. During the classes I took a few notes. Nothing structured, but I'll comment what I think it can be interesting here:


    Internesting option if you are playing with mongodb in your laptop and you don't want him to prealocate all the journal. You may be interested in reducing the size of the ...

  3. Networking of the sandbox

    Today was the day to configure the network of my sandbox. My boss told me that in order to have a controlled test environment I should have my own router and switch. We have a Cisco router unused and a switch and I've set all up.

    Basically the hardware was old and we didn't event knew the passwords to access so I've had to do a factory reset. On the switch has been really straightforward; there is a "Reset" mini-button on the chassis. Just press it when ...

  4. Stuff for playing

    A friend of mine, lets call him Gigi, made me a very special present. He works in a Big Company, and they are swimming in money. I don't know how they internally manage their IT department but it seems that every now and then they throw away all the old hardware they have and buy new servers/routers/switches. Can't really understand why, but when the money is not an issue I guess is an easy way to plan the yearly budget.

    Anyway, they were throwing away some ...

  5. AWS Advanced Operations course

    I've done the Advanced Operations course of AWS in CAPSiDE, the company where I'm working. We are the only official AWS formation center in Spain so if you want to get some classes just contact us. If you are in UK maybe you want to come to Spain to receive the course because in London there are a waiting list of months, depending on the course.

    It's a four day course and I think is the most advanced course of AWS in this subject. I've really ...

  6. MySQL my.cnf file

    Quick entry. If you are usually connecting to a local or remote mysql database you have to enter the password every single time you enter "mysql". Of course there is a way to configure it in a way that the password is not required:

    Let's doit for the root user.

    $ sudo -i
    $ cat > .my.cnf << EOF
    user = root  
    password = qweqweqwe  
    host = localhost
    $ chmod 600 .my.cnf
    1. The first command is for having root privileges.
    2. The second command creates a file called .my.cnf (it MUST be this ...

  7. Sending mails from my VPS to my private mail

    OK, it is a shitty post about something you already know, is like the SUID one. Things that I should know but for some odd reason I never spend enough time to "get it" and it has been a grey area for me.

    That's the case of sending mails from one of my VPS, without configuring any MTA, any SMPT server or anything. Just as it comes. The idea is to be able to do something like:

    $ echo 'Hello world' | mail -s 'Mail from your server' test@jcarreras.es ...

  8. Restoring AWS snapshot kernel leads us to a beautiful kernel panic

    [Use the same ARI]

    For the ones who don't know: if you are restoring a snapshot of your instance by creating a new AMI from the snapshot and then create a new instance from the AMI, you must use the same Amazon Kernel Image (AKI) as the original instance when you are creating the AMI.

    It is not required (as far as I know) to define the Amazon Ramdisk Image (ARI) parameter exactly the same as the original instance, but you must select the same kernel version or you ...

  9. Vodafone is hijacking my DNS requests

    How I know it? Easy. I have tree hosts: my own laptop, liz a VPS in Germany with IP  and abbie a VPS in USA.

    # I don't even have a DNS server installed on this host (liz)
    $ ssh root@  tcpdump 'port 52'

    And now I run from my laptop (the one that is conected to my ISP, Vodafone):

    $laptop> dig +short @ goatse.com

    And I get two results. How ...

  10. fail2ban, molly-guard and logwatch. Programs of the week.

    Recently in a awesome thread in HN I've learnt about this awesome programs: file2ban, molly-guard and logwatch.


    Well, I really knew that program before, but I thought that was kind of difficult to configure. It seems that the default options are really good. I make intensive use of the iptables firewall in my servers and it is nice that you can have an utility that adds/removes rules when something is trying to do bad things to you. Haven't really explored all the options of file2ban, but ...

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