Azitech

Azimout's Linux weblog

Upgrade to CM11

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After freeing my Android a year ago, I decided to upgrade to a more up-to-date version of Android/CyanogenMod.

At first I upgraded from CM 10.1 to 10.2; however, many Google apps gave me a “cannot contact Google servers” error (mainly GMail, Google Calendar and Google Play; Maps worked fine).

I tried reinstalling the gapps .apk, I tried clearing the cache, I tried a factory reset and reinstalling CM. Nothing seemed to work. In the end, thanks to some forum thread I realized that maybe it does not work when you have 2-step authentication for your Google account (the authentication itself seemed to succeed on the phone, but then the sync services failed).

So, eventually I decided to try to upgrade to CM 11 nightly. The new problem was that the disk image would fail to install (some error about a get_metadata_recursive method). After some googling I realized that I needed a newer version of the ClockworkMod recovery, 6.0.2.3 just wouldn’t cut it. So I downloaded 6.0.4.6 and heimdall and tried flashing it, which also didn’t work (error message: no recovery partition found).

The solution was to install Rommanager and upgrade the CWM recovery from there. After that, I could install CM 11 and the corresponding Gapps, and now everything seems to work fine.

Written by azimout

02/03/2014 at 08:41

Posted in Problems

Rotate videos from the command line

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To rotate a video from the command line, use avconv (contained in the libav-tools package), which used to be called ffmpeg.

For a single file, type:

avconv -i original.mp4 -vf "transpose=1" rotated.mp4

Written by azimout

10/02/2014 at 09:45

Posted in Howto

pstree

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A rather useful Linux command that allows you to see all processes run by a user, along with their PIDs, in a tree format is pstree -Ap <user>

Written by azimout

09/01/2014 at 16:18

Posted in Uncategorized

Munin

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Installing munin on a Ubuntu system is very simple:

  • sudo apt-get install munin munin-node
  • sudo vi /etc/munin/apache.conf, remove the “Allow from” line and add “Allow from all”
  • sudo service apache2 restart

Now you can see your munin graphs on http:/myserver/munin (replace “myserver” with the URL of your server)

(I am assuming that you already have Apache running)

Architecture: Munin has a master (munin) which connects to one or multiple nodes (munin-node), collects data, produces the graphs and serves the html. In this simple case, there is only one node, which is the same as the master.

Disabling plugins: Munin comes with several plugins, some of which you might not care for. All plugins are installed under /usr/share/munin/plugins, and the enabled ones are symlinked-to under /etc/munin/plugins. So, to disable one, just remove the corresponding symlink under /etc/munin/plugins

For debugging the munin plugins, a useful command is this:
sudo /usr/sbin/munin-node-configure --suggest

Apache stats: In order to see statistics about Apache, you need to sudo a2enmod info

If you have Drupal installed with mod_rewrite enabled for clean URLs, you need to add the following line to the mod_rewrite section of the .htaccess file at the root of your Drupal installation, as described in this thread; otherwise, you’ll get a 404 error.

RewriteCond %{REQUEST_URI} !=/server-status

In order to test if this is enabled, type this:
links http://localhost/server-status

MySQL: Edit file /etc/munin/plugin-conf.d/munin-node, and in section [mysql*], add the following line:

env.mysqladmin /usr/bin/mysqladmin

Also, it might be a good idea to disable the following two (remove the symlinks in /etc/munin/plugins), as they’re currently broken: mysql_innodb, mysql_isam_space_

Run manually: If you’ve made changes to the munin configuration and want to test them without waiting for the 5 minutes to pass, run this command:

sudo -u munin /usr/bin/munin-cron

Written by azimout

25/12/2013 at 18:55

Posted in Reference

Nagios

with 2 comments

Here’s how you can set up a Nagios server in order to monitor a publicly accessible website and get an email notification when it’s down.

On the monitoring server:

Now create a .cfg file under /etc/nagios3/conf.d with the following contents:

define host {
        use             generic-host
        host_name       xxx
        alias           xxx
        address         xxx
        }
define service {
        use             generic-service
        host_name       xxx
        service_description     HTTP
        check_command   check_http
        }

(replace all instances of xxx with the appropriate values)

Now restart Nagios: sudo service nagios3 restart

Any notifications will be emailed to root@localhost

References:

Written by azimout

22/09/2013 at 20:06

Posted in Howto

How to install request tracker in Ubuntu

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  • sudo apt-get install request-tracker4 rt4-db-mysql rt4-apache2 libapache2-mod-fcgid
  • sudo cp /etc/request-tracker4/apache2-fcgid.conf /etc/apache2/sites-available/rt4
  • sudo a2ensite rt4; sudo service apache2 restart

To edit RT’s configuration, don’t edit directly the file /etc/request-tracker4/RT_SiteConfig.pm. Instead, change the files (or add one) under /etc/request-tracker4/RT_SiteConfig.d/*, then run sudo update-rt-siteconfig

Written by azimout

03/07/2013 at 10:17

Posted in Howto

Byobu function keys from PuTTY

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In order to get the F2, F3, F4 and other function keys used by Byobu work when connecting with PuTTY on Windows, set “function keys and keypad” to “Xterm R6″ under “Keyboard” in the PuTTY settings.

Written by azimout

20/06/2013 at 14:50

Posted in Tricks

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