Author: halfgaar (Page 8 of 26)

Halfgaar is Wiebe. Wiebe is a contributing author on this weblog. He also has a lot of stuff (such as long, in-depth articles) on his personal website.

Wiebe's day job is as a senior software developer and system administrator at YTEC.

In his free time, he built the free, open-source FlashMQ software. Together with Jeroen and Rowan, he is now building a managed MQTT hosting business around his open masterpiece.

Some links about Macbook sleep problems

December 20, 2012 / halfgaar

My wife’s macbook sometimes keeps waking up when you close it; it gets stuck in an endless sleep-wakeup loop. Here are some links about it that I’ve had in my e-mail forever:

Apple forum discussion

Maintain tool

The problem had to do with Bluetooth, apparently.

Getting munin to run every 10 minutes

December 18, 2012 / halfgaar

Munin is kind of inefficient and on my P4 2Ghz, it running every 5 minutes is too often, and the munin processes keep dying because locks already exist. You can’t increase the munin-cron script to 10 minute intervals, because then rrdtool will generate gaps.

The munin-cron script is nothing but a wrapper for munin-graph, munin-html and munin-update. I made my own wrappers, which I then run with separate cronjobs:

# cat /usr/local/bin/munin-graph 
#!/bin/bash
 
# file copied from /usr/bin/munin-cron and adjusted.
 
# This used to test if the executables were installed.  But that is
# perfectly redundant and supresses errors that the admin should see.
 
#/usr/share/munin/munin-update $@ || exit 1
 
# The result of munin-limits is needed by munin-html but not by
# munin-graph.  So run it in the background now, it will be done
# before munin-graph.
 
# When runnin update at */5 and graph at */10, munin-update and munin-graph
# will be started at the same time, and this sleep it to prevent a
# race-condition on the update-running file.
sleep 5
 
while [ -f "/var/run/munin/update-running" ]; do
        sleep 1
done
 
/usr/share/munin/munin-limits $@ &
 
nice /usr/share/munin/munin-graph --cron $@ 2>&1 | fgrep -v "*** attempt to put segment in horiz list twice"
 
wait
 
nice /usr/share/munin/munin-html $@ || exit 1

# cat /usr/local/bin/munin-update-data
#!/bin/bash
 
# file copied from /usr/bin/munin-cron and adjusted.
 
# This used to test if the executables were installed.  But that is
# perfectly redundant and supresses errors that the admin should see.
 
runfile="/var/run/munin/update-running"
touch "$runfile"
 
/usr/share/munin/munin-update $@ || exit 1
 
rm "$runfile"
 
# The result of munin-limits is needed by munin-html but not by
# munin-graph.  So run it in the background now, it will be done
# before munin-graph.
 
#/usr/share/munin/munin-limits $@ &
 
#nice /usr/share/munin/munin-graph --cron $@ 2>&1 | fgrep -v "*** attempt to put segment in horiz list twice"
 
#wait
 
#nice /usr/share/munin/munin-html $@ || exit 1

# cat /etc/cron.d/munin
#
# cron-jobs for munin
#
 
MAILTO=root
 
#*/5 * * * *     munin if [ -x /usr/bin/munin-cron ]; then /usr/bin/munin-cron; fi
*/5 * * * *     munin if [ -x /usr/local/bin/munin-update-data ]; then /usr/local/bin/munin-update-data; fi
*/10 * * * *    munin if [ -x /usr/local/bin/munin-graph ]; then /usr/local/bin/munin-graph; fi
14 10 * * *     munin if [ -x /usr/share/munin/munin-limits ]; then /usr/share/munin/munin-limits --force --contact nagios --contact old-nagios; fi

Adding a clock in screen to avoid your ssh’s from being killed

October 31, 2012 / halfgaar

The world is filled with stupid routers, which kill all connections that have no activity for a while (even a very short while). I keep loosing my SSH sessions because of this. To fix it, I added a clock in my GNU screen bar:

hardstatus alwayslastline "%= %H | %l | [%c:%s]"

For the record, my entire .screenrc:

multiuser on
caption always "%{= kB}%-Lw%{=s kB}%50>%n%f* %t %{-}%+Lw%<"
vbell off
startup_message off
term linux
hardstatus alwayslastline "%= %H | %l | [%c:%s]"

Converting all tables in MySQL DB to InnoDB

October 2, 2012 / halfgaar

#!/bin/bash
 
exit 1
 
dbname="eorder"
 
echo 'SHOW TABLES;'  | mysql $dbname  | awk '!/^Tables_in_/ {print "ALTER TABLE `"$0"` ENGINE = InnoDB;"}'  | column -t 
echo 'SHOW TABLES;'  | mysql $dbname  | awk '!/^Tables_in_/ {print "ALTER TABLE `"$0"` ENGINE = InnoDB;"}'  | column -t | mysql $dbname

Translating Dutch programming error messages

August 9, 2012 / halfgaar

In .NET, you get Dutch errors when your Windows is in Dutch, which is hugely annoying. You can use this site to translate them, so that you can Google them.

My universal remote programming codes

August 6, 2012 / halfgaar

Whenever this remote’s battery is loose for a while, it forgets its programming. So, here it is:

For computer, use the TV setting. Press 1 and 3 for a few seconds, then when the light turns on, enter 0677 as code.

For my amp, you have to set the aux mode for a second TV. To do that, press 1 and 6 for a while. Then press 9, 9, 2. Then press TV, then aux. Next step is to enter the TV code. Press aux, then hold 1 and 3. Enter the following code: 0064.

Kart racing scores

July 25, 2012 / halfgaar

I want to keep track of my kart racing scores:

date	Track	Racer	fastest Time
2012-07-24	Long Beach	Wiebe	55.95
2012-07-24	Long Beach	Wiebe	56.22
2012-07-24	Long Beach	Wiebe	58.84

Apache mod_proxy configuration for The Pirate Bay

July 13, 2012 / halfgaar

I found several apache mod_proxy configs for setting up a proxy for The Pirate Bay, but none worked fully.

You need to enable/install:

mod_proxy
mod_rewrite
mod_headers
mod_proxy_http

<Virtualhost *:80>
        ServerName tpb.yourdomain.com
 
        # Plausible deniability, and respecting your fellow pirate's privacy.
        Loglevel emerg
        CustomLog /dev/null combined
        ErrorLog /dev/null
 
        <Proxy *>
          Order deny,allow
          Allow from all
        </Proxy>
 
        # Just to fix a few links...
        RewriteEngine On
        RewriteRule \/static\.thepiratebay\.se\/(.*)$ /static/$1 [R=302,L]
 
        ProxyRequests off
 
        # Cookies are imporant to be able to disable the annoying double-row mode.
        # The . before the domain is required, but I don't know why :)
        ProxyPassReverseCookieDomain .thepiratebay.se tpb.yourdomain.com
 
        ProxyPass / http://thepiratebay.se/
        ProxyPass /static/ http://static.thepiratebay.se/
        ProxyPass /torrents/ http://torrents.thepiratebay.se/
        ProxyHTMLURLMap http://thepiratebay.se /
        ProxyHTMLURLMap http://([a-z]*).thepiratebay.se /$1 R
 
        ProxyHTMLEnable On
 
        <Location /static/>
          ProxyPassReverse /
          SetOutputFilter proxy-html
          ProxyHTMLURLMap / /static/
          RequestHeader unset Accept-Encoding
        </Location>
 
        <Location /torrents/>
          ProxyPassReverse /
          SetOutputFilter proxy-html
          ProxyHTMLURLMap / /torrents/
          RequestHeader unset Accept-Encoding
        </Location>
 
</Virtualhost>

Listing MySQL table sizes

July 12, 2012 / halfgaar

This query lists the sizes of all tables in MySQL:

SELECT 
  TABLE_SCHEMA, 
  TABLE_NAME, 
  CONCAT(ROUND(data_length / ( 1024 * 1024 ), 2), 'MB') DATA, 
  CONCAT(ROUND(data_free  / ( 1024 * 1024 ), 2), 'MB') FREE 
from information_schema.TABLES 
where TABLE_SCHEMA NOT IN ('information_schema','mysql', 'performance_schema');

This query lists the database sizes:

SELECT 
  TABLE_SCHEMA, 
  TABLE_NAME, 
  CONCAT(ROUND(sum(data_length) / ( 1024 * 1024 ), 2), 'MB') DATA 
from information_schema.TABLES 
where TABLE_SCHEMA NOT IN ('information_schema','mysql', 'performance_schema') 
group by TABLE_SCHEMA;

Generating an SSL CSR and key

May 10, 2012 / halfgaar

To generate an SSL certificate signing request (CSR) with key you can do this:

openssl req -nodes -newkey rsa:2048 -keyout bla.key -out bla.csr

This syntax does not force you to supply a password, which is convenient.

If you generate a CSR for startcom, you don’t have to fill in any fields; only the public key from the CSR is used. For other vendors, the common name is important; the domain name must be entered there.