Docker image cleanup

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Running docker frequently can lead to mysteriously disappearing space. I kid, its not mysterious. Each image builds a layer which in turn eats up space. Logical but PITA!

Put this in your .bashrc or run it as cron on your docker host to clean up.

docker rm -v $(docker ps -a -q -f status=exited)
docker rmi $(docker images -f “dangling=true” -q)

or do it in one alias (use at your own discretion)

alias docker_janitor='docker rm -v $(docker ps -a -q -f status=exited);docker rmi $(docker images -f “dangling=true” -q)'

sounds too easy..


Running RTC as a Windows service

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I need to run the Rational Team Concert Jazz Build Engine as a Windows service as we need it to run non-stop as part of the continuous integration service. The catches though are

  • it (theoretically) wouldn’t stop as it keeps on waiting for build requests from the RTC server. This makes it as an unlikely candidate for scheduled tasks unless I will cookup a script for terminating it before the actual run. Messy if I still have to check if there is a build in progress.
  • the machine hosting it is not a dedicated machine so a couple of admins usually login to do some stuff which kills any running processes executed by the currently logged-in user.

Windows provides the sc.exe utility for creating and removing Windows services but it only accepts executables and not scripts. I have to set some environment properties and parameters so this is out of the running. The Java Service Wrapper is a good alternative but I misread the instructions so ended up using the AutoExnt utility in the Win2003 Resourse Kit. The files are still usable in Windows XP.

Only three files are needed from the kit namely Autoexnt.exe, instexnt.exe and servmess.dll. These files are to be dropped in the %SYSTEMROOT%\system32 directory.. The next step is to create the %SYSTEMROOT%\system32\autoexnt.bat (the file needs to be named like that) with the commands to be executed. My script looked something like this:

@echo off
REM Workstation specific settings.
set JBE_Eclipse_Dir=C:\Apps\IBM\jazz\buildsystem\buildengine\eclipse
set JBE_Repository_URL=https:///jazz
set JBE_EngineID=ToolingBuilder
set JBE_user=kerberos
set JBE_password=

REM If proxy is not needed, switch the JBE_VMArgs_OPTS to use the empty one
set proxyHost=
set proxyPort=3128

set JBE_VMArgs_OPTS=-vmargs -DhttpsproxyHost=%proxyHost% -Dhttps.proxyPort=%proxyPort%

REM Set the JVM to use to the IBM J9 VM otherwise the compilation will fail.
set java_home=C:\Apps\IBM\SDP70\jdk
set classpath=.;%java_home%\lib
set path=%java_home%\bin;%path%

REM Invoke the Jazz Build Engine client.
pushd %JBE_Eclipse_Dir%
jbe.exe -repository %JBE_Repository_URL% -userId %JBE_user -pass %JBE_password% -engineId %JBE_EngineID% -sleeptime 1 %JBE_VMArgs_OPTS%


The next step is invoking the command instexnt install to install the service. The only final thing to do is to go inside the Services console of Windows and reconfigure the AutoExNT service to start automatically at boot up. Of course, it needs to be started as well if you want to use the service immediately. 🙂

There are a few more help in the Windos 2003 Resource Kit help but the only thing of interest is using instexnt install /interactive to install the service. This will cause the service to pop out a command window wherein the user can view the console output. The downside is that the user can close the window which will terminate the service.

I have thought about migrating the system to use the Java Service Wrapper but using the AutoExNT separates the service component which allows JBE implementors to replace/delete the JBE installation directory without going through the setup process again.

[edit 20081002] Dom Weinand posted this link in the RTC user forum on how to use the Java Service Launcher to run JBE as a Windows service[/edit]


LLTHW: Importing Eclipse projects

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I thought I was starting a new acronym but it seems NetHack has already first dibs on Lessons Learned The Hard Way. 😀 Anyway, any posts that I tag with this acronym should be self-explanatory. 😀

One of the training machines we are using is encountering a weird error because the user could not launch the plugin project for debugging. To make the matters worse, the error message just contains an empty string. The other machines does not seem to exhibit the problem.

After an hour of trial and error, we finally figured out the problem. Eclipse does not like importing projects that are placed in the C:\ (or root drive). The solution was to place the project code base in a intermediary directory (C:\Something) and then proceed with importing it in the workspace.

I do not know the rational explanation for this one and my initial google searches does not reveal anything that is remotely related. I will just chalk this one as a lesson learned the hard way.


One liner: get the last field

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Problem: I need to get a list of all java libraries in our repository so I can create a matrix of when they are being used and what is type of license they are using. I tried using a pure Windows approach but it is taking too much time so I used Cygwin instead. Getting all JAR files is easy with find but I am having difficulty brewing the correct regexp syntax so why prolong the agony and not switch to another tool instead: awk!

find . -name *.jar | awk -F/ ´{$NF}' | sort | uniq


– find searches recursively from the current directly for all files that end with ‘.jar’
– all resulting file paths are piped to awk which, using the forward slash as the column delimiter, prints out the last column
– and finally the list of JAR files are sorted alphabetically and duplicates are removed.

This could probably be done in a whole lot of ways (perl, python, sed, etc.) but the beauty of FLOSS is we can use whatever we can to get the same result. 😀


Blog migration completed


The migration of the pertinent posting and comments have been completed from the blogsome account. It may look like most of the comments were made by a single man but that is one of the drawbacks of manual migration. 🙂

The xml-rpc page of this site does not seem to work as well as the feeds section but that is something to do in the future.


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