Videos

So, I've been working on making screencapture/narration videos, and after a bit of effort I got it to work. I used recordmydesktop, and it does most of what I want. My main gripe with it is that th e audio is soft on it, and it is unclear how to boost it. Another problem encountered is that it saves the files as ogg/theora video files, which crash the video player if the resolution chosen is too large. The files it creates are fairly large.

I did do some transcoding, the lab machines can not handle 1024x768 resolution, so I used

vlc -I dummy out.ogg vlc:quit --sout "#transcode{vcodec=theo,scale=0.75}:duplicate{dst=std{access=file,mux=ogg,dst=\"three.ogg\"}}"

to change the size and

mencoder out.ogg -ovc lavc -oac mp3lame -o full.avi

to change the container to avi.

I know I could probably use transcode directly, but these worked well enough and was faster to find.

I tried audacity for podcasts and it seems pretty cool. I had problems getting the playback configured, but the recording went well.

Update: 9/26
some students had problems with it, so I am trying the following two encodings
mencoder loan_spreadsheet_1280x768.ogg -o loan_spreadsheet_1280x768.flv -of lavf -oac mp3lame -lameopts br=192 -af lavcresample=22050 -srate 22050 -ovc lavc -lavcopts vcodec=flv:vbitrate=2000:autoaspect:mbd=2:trell:v4mv -lavfopts i_certify_that_my_video_stream_does_not_use_b_frames

there also is a scaling option -vf scale=640:480 that I didn't use, but the example I found did.

and
mencoder loan_spreadsheet_1280x768.ogg -ovc xvid -oac mp3lame -o out.avi -xvidencopts bitrate=687


I had wanted to include a quicktime version, but the codec isn't on this machine.

Package synchronization

I looked at a bunch of different tools for package/config management. None of them do what I would like though (and some are complex and brittle too).

Basically I just want to keep all of the files synchronized with each other, with a few files fixed. It is tempting to want to remote mount /etc, but I worry about performance and reliability of such an approach. Plus I would need to use something like a unionfs to handle the machine specific files.

So, I've been writing a database app that checks the packages that are installed and looks for abnormalities. It isn't perfect, but it is a step in the right direction. The next stage is to check the consistency of the files. I've been developing a web interface via Catalyst for this as I go. It hasn't been great, but it seems adequate.

It is surprising to me, how many differences evolve over time.

Another thing that would be nice to have, is a catchup mode to bring a new machine up to speed. For instance I have two machines in the hawkins lab that need to be redone, and I just redid two in the redcay lab.

sql sequences

This was useful for setting up some databases

insert into machine select s.a, s.a from generate_series (101, 140) as s(a)

USB Automount

I found the problem with the usb automounting/mounting

When the users were authenticated via ldap, they were not getting the correct permissions. Essentially they have to be assigned the correct groups, to do this the common-auth, common-session, and gdm config files in /etc/pam.d need to be updated, and the /etc/security/group.conf file needs to be set up. It is working now, but it took several hours of searching and trial and error to get right, blech.

mdadm sucks

really annoyed at mdadm, I've tried for over an hour to get it to deinstall remotely, but it insists that I must login to deinstall it in person. It is somewhat understandable, but I have about 60 machines and it is a real pain in the but to log into each one of them.

It wouldn't have been so bad, but it was something that was installed as part of the upgrade process, and I didn't go through all 800 odd packages that were part of the upgrade.

Authentication

Met with Symen about the authentication system. We have a new LDAP group, actually two, and he helped me set up the ldap authentication so it found them correctly.
Notes:
- pam_ldap_filter did not seem to be used at all, only nss_passwd_base
- be careful with parenthesis, apparently the system auto adds some parentheses to the queries, so your query is really just a substring that is injected into the real query.
- http://www-unix.mcs.anl.gov/~gawor/ldap/applet/applet.html is a cool applet, although there should be some better ldap editors around.

It turns out that the user that I needed to set up the LDAP group for, is now in the first group anyways. Oh well, it still may be useful.