# Editing component files with vim

Editing LCFG component source files using Vim is of course The Right Thing to do, but due to the way these source files are named (typically filename.ext.cin) vim doesn’t necessarily pick up on the filetype, and goodies such as syntax highlighting are lost.

This is easy to fix using vim’s ftdetect system. Some examples for simple types:

" These files are always POD in disguise
au BufRead,BufNewFile *.pod.cin : set filetype=pod
" Slightly contentious: a new filetype is needed, really, but this is a decent match.
au BufRead,BufNewFile *.def.cin : set filetype=cpp
" For other, unknown types, detect from the as-yet undefined shebang:
au BufRead,BufNewFile *.cin : if getline(1) =~ '^#!@SHELL@' | set filetype=sh | endif
au BufRead,BufNewFile *.cin : if getline(1) =~ '^#!@PERL@' | set filetype=perl | endif


(note the latter two lines are specified separately, rather than elseifed, purely for readability). It’s fairly obvious that this can be extended to any file type, and there’s also scope for adding an automatic mapping to allow all files of form file.typ.cin to be mapped automatically to their default .typ. “sub-extension” file type.

Anyway, the above has already improved my productivity no end so I’ll leave the latter exercise to the reader. Comments and contributions are welcome, as always — so long as they’re not suggestions to use Emacs(!)

# Away with the PXEs

Occasionally, for the purposes of internal testing or continuity, it’s desirable to bring up a server with a duplicate MAC address. It’s a safe enough manoeuvre (so long as these machines operate on different wires) for the brief periods in which I require it but when this scenario involves the installation of a new server via our installroot PXE service, things are trickier.

Our PXE server is configured automagically by spanning map and, effectively, keyed on MAC, so it’s unlikely to present the correct configuration (reliably) when the new host differs from the old one in some way.

The workaround is to override the PXE configuration on the *existing* server (on the basis that you weren’t planning on reinstalling it, anyway, were you?):

!pxeclient.platforms mADD(new_plat_name) /* e.g. sl6_64 */

/* And, if you need to add or remove serial console support: */
!pxeclient.serial_port mSET(ttyS0) /* or () */


Post-PXE, the dhclient component is aware of subnet differences and will ensure your machine receives the correct profile for installation (though, to prevent future confusion, remove this as soon as the installer has done its work!).

# LCFG and Very Big Disks

(By the time you read this, 6Tb of disk is probably not that big any more…)

Handling a new server which required a 4Tb (RAIDed) Data partition turned out to be a bit of a hassle. Continue reading

# Updating Matlab Licences

This is simpler than it used to be, but is a bit of a convoluted process, so I thought it worth detailing.

When our Matlab licences are renewed or added to by request, Informatics will receive a new licence file (apparently known as a “license file” to those living west of us). This will look something like:

# LicenseNo: 123456   HostID: 000000001122
INCREMENT MATLAB MLM 20 01-jan-[...] \
VENDOR_STRING=[....] \
DUP_GROUP=[...]
INCREMENT GADS_Toolbox MLM 20 01-jan- [...] \
VENDOR_STRING=[...] \
DUP_GROUP=[...]
[...]


Note the absence of SERVER and VENDOR lines: other FlexLM vendors provide these lines, but I’ll talk about this later. It’s worth noting that if either line is present in a Matlab licence file, it should be removed.

This file needs to be packed into our matlab-license rpm. Retrieve the latest SRPM (be careful, sometimes the dates are more instructive than the versions!) and install it to your RPM build directory. You’ll find a tarball along the lines of matlab-license.tgz — this has a directory structure resembling:

matlab-license/


Note that the licences are built from multiple files in each of the teaching/ and research/ directories. Let’s say we’re replacing the research licence, since this file is the more complex of the two.

$cd /tmp/$ tar -zxf ~/RPM/SOURCES/matlab-license.tgz
$less matlab-license/etc/research/license.dat # MATLAB license passcode file. # # This portion contains the main set of research licences # LicenseNo: 123456 HostID: 000000001122 INCREMENT MATLAB MLM 20 01-jan-[...] \ VENDOR_STRING=[....] \ DUP_GROUP=[...] INCREMENT GADS_Toolbox MLM 20 01-jan- [...] \ VENDOR_STRING=[...] \ DUP_GROUP=[...] [...]$ less matlab-license/etc/research/other.dat
#
# This portion contains Some Other licences
INCREMENT MATLAB MLM 21 01-jan-0000 11 3D20000[...] \
[...]


It’s important to note that these files might have come from different accounts and it is likely that we are only replacing one of the files — possibly none if this is a brand-new addition. If we’re replacing just the main Research licence, we need to leave the other files alone; if we’re adding a new licence, simply add a file to the research directory with any name you wish (so long as it ends .dat).

Paste your replacement licence INCREMENT lines into this file. Tgz the file back up and place it in SOURCES.

Once your new tarball is back in sources, you need to amend the specfile. Update any matlab versions amongst the %defines at the top of the file, and increment or reset the Release as appropriate. Build and submit as normal:

$rpmbuild -bs SPECS/matlab-license.spec$ pkgforge submit -B inf -p sl5,sl6 SRPMS/matlab-license-x.y-z.noarch.rpm


(Note that this will submit new matlab-license-teaching, matlab-license-research and other RPMs. If there are no major version changes and we’re simply modifying the research licence, it’s OK just to deploy the matlab-license-research RPM, but it’s good practice to submit them all, and certainly the SRPM.)

Continuing our assumption that we’ve just made a trivial change to the research licence (a new INCREMENT line for example), edit the dice/options/matlab-research-server.h and live/matlab-research-server.h headers to include the new RPM:

$svn di core/include/dice/options/matlab-research-server.h +!profile.packages mEXTRA(+matlab-license-research-7.7_7.8-7.inf/noarch)$ svn di live/include/live/matlab-research-server.h
+/* REMINDER: Remove this next Friday! */
[...]


Finally, if we need to lock down one of our new licences to a specific user, we can do this using the live header and the FlexLM component’s options-file support:

$svn di live/include/live/matlab-research-server.h [...] +/* RTxxxx: Reserve one Statistics Toolbox licence */ +!flexlm.options_research mADD(gr1 re1) +flexlm.option_research_gr1 USER_GROUP gr1 userone usertwo userthree +flexlm.option_research_re1 RESERVE 1 "Statistics_Toolbox" USER_GROUP gr1  Clearly, this reserves one Statistics Toolbox licence for the given group of users. Having made all these changes, commit to the repository. You can push the required changes to the FlexLM server without restarting: the FlexLM component will perform a reload on picking up the options-file changes, though these may not make sense until updaterpms is run so the recommended intervention is as follows: [matlab-research]$ om updaterpms run
[INFO] updaterpms: 1 installs, 0 removals
[WAIT] updaterpms: Checking dependencies

[matlab-research]\$ om flexlm configure
om flexlm configure
[INFO] flexlm: Reconfiguring /usr/lib/lcfg/conf/flexlm/research
[OK] flexlm: configure


You may check the result of your actions by examining the Flexlm web-status page, which for the Research matlab licence is http://matlab-research:1881/usage-research.html. This should detail your new licences in the upper section, and any reservations alongside the list of ‘in-use’ licences in the lower section.

Be aware: if you make a mistake with INCLUDE, EXCLUDE and RESERVE lines and have to change them, reservations can end up becoming locked. A restart of the FlexLM server will clear this but it’s worth knowing in case you’re wondering where a licence went!

For more information on configuring FlexLM, see the relevant RAT Unit documentation pages for FlexLM and Matlab, and also the lcfg-flexlm manual page (the definitive reference for configuring a lcfg-flexlm server).

UPDATED 15/03/2012 to reflect the updated RPM procedure where licences are automatically constructed from their constituent parts in etc/{research,teaching}.

# monitoring postgresql

This should serve as yet another account of “naïve” addition of monitoring to an LCFG component.  It proved to be surprisingly straightforward: PostgreSQL on my test server is now being monitored; built-in support is now available on any host:

#include <dice/options/postgresql-monitoring.h>

though take care to follow the instructions within.