From: Petter Reinholdtsen Date: Mon, 11 Jul 2005 18:54:12 +0000 (+0000) Subject: First draft. X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/commitdiff_plain/be469765257999c35e451ed09ab214493ce33d77?ds=inline First draft. --- diff --git a/mypapers/enterprise-software/enterprise-software.html b/mypapers/enterprise-software/enterprise-software.html new file mode 100644 index 0000000000..53f168771f --- /dev/null +++ b/mypapers/enterprise-software/enterprise-software.html @@ -0,0 +1,207 @@ + + + + + + + + + + +

Writing enterprise ready software

+ +

http://www.hungry.com/~pere/mypapers/enterprise-software/enterprise-software.html

+ +

Petter Reinholdtsen +
pere@hungry.com +
Debconf5, Helsinki 2005-06-12

+ +

Overview

we are in trouble +
clues for the clueless +
multilevel configuration + +

+ +

We are in trouble

+ +

With 60000 users and about 150 home directory file servers + available from 12000 machines, users move from file server to file + server. This break several applications when the path to the users + home directory changes. (example: /mn/hegel/u1/pere to + /usit/saruman/u1/pere).

+ + + +

More trouble

+ +

With 900 linux machines with common user database and home +directories while running different versions of programs, users will +run several versions of a program with the same configuration +files.

+ + + +

Some old trouble

+ + +

Some users lost the source of their production systems, and need +the binaries to keep working for 10-15 years.

+ + + +

No room for more trouble

+ +

When the file system for the PostgreSQL database in production goes +full, one do not want to kick out 30000 users to take down the +database and resize the file system.

+ +

Disktrouble

+ +

RAID is only only useful until the last redundancy disk is lost. + +

Automatic RAID status systems need API or command line tools to +extract the status. Not like afacli, which go into interactive mode +when an error is detected. + +

Installation trouble

+ +

Trying to compile/install software on Irix, Solaris, Linux, HP-UX, +Tru64 Unix, MacOSX and AIX when the process require a sysadmin to sit +around to answer questions, change CDs, or insert licenses is both +painful and prone to errors.

+ +

Network trouble

+ +

Trying to get some network server to work when it require to use +some given port range, which is already taken by some other service +and blocked in the router -- or try to get the coorporate network +gatekeeper to open up the firewall

+ +

Version trouble

+ +

Given three tcl or php applications, is there one version of TCL or +PHP usable with all of these? + +

Usability trouble

+ +

When starting a program from the meny, where does it go if nothing +appear on the screen? + +

Do users always read their ~/.xsession-error file? + + +Providing hooks to the local admins + +backdoor - alternative way in. fixing 800 machines by hand is not +possible. - ssh config fuckup + +reduce flexibility. trying to support people over the phone when the +gui is different for every person is a pain. + + +

Clues for the clueless

+ +

at least three levels of config files; package defaults, site + defaults and host defaults + +
never ask questions at compile time. when compiling automatically + for 10 platforms, a sysadmin do not want to sit down and answer + questions. + +
split installation tasks in two, one for installation, and one for + the operations needing root access. (build / configuration as well) + +
make sure the software can be installed anywhere (location + independent), avoid hardcoding paths into the binaries. + +
make the source available to make it possible to fix problems on + site, and to use it on different platforms (os/hw) in the future + +
Make paths into users home directories relative to ~user/, as users + will move from disk to disk, or copy their home directory from site + to site. Always convert paths when saving config files. + +
depend on as few libraries as possible, as it is a pain to get every + extra library in place + +
use well known libraries instead of making your own implementation. + reduses the security risk. + +
make sure libraries, and programming languages are backwards + compatible. + +
use a well known license. it is a pain to evaluate every new + license + +
when distributing source, do not use vendor specific compiler + features. It will not work with the other vendors compilers used to + compile on site. + +
write portable code, make sure it works the same on all platforms. + +
make the software work out of the box (require as little + configuration as possible). + +
avoid resource leaks (memory, shared memory, locks, file + descriptors, X server resources, etc). Restarting a long-running + server is not always an option. + +
system services should send messages to syslog. always log why when + crashing. always log problems and errors. + +
reuse configuration. ktouch have its own x layout setting. + better to fetch the current one from X like xkeycaps. + +

+ +

Solving the upgrade problem using multilevel + configuration

+ +

local configuration should be kept during upgrades
easiest to do if the local configration is separate from the + package default + +
several actors what to have a say in the service + configuration. allow them to have their own files + +
Example: read config from /usr/share/foo/config, + /site/share/foo/config, /etc/foo/config, ~/.foo/config, + /etc/foo/config.fixed, /site/share/foo/config.fixed, + /usr/share/foo/config.fixed. + +
make it possible to provide package, site, host and user + defaults, as well as locking down features on a host, site and + package level. + +
always well known where the admin made his changes + +

+ + + +

Thank you very much

+ +

Questions?

+ + +