DB2 9.1 Installation notes for Ubuntu 10.04
Installing DB2 on quite recent Linux systems (like Ubuntu 10.04) goes smoothly as described on instructions on this site. You will notice that DB2 is up and running, you can even create sample database, but there is one problem. No application, whether it is IBM Data Studio or some PHP application, cannot connect to database.
Reason is very simple. Ubuntu 10.04 like many other installations use SHA512 password encryption by default. This is not a problem for DB2 9.7, but DB2 9.1 is limited to md5. And remedy is also very simple if you know it, otherwise you’ll be banging your head to wall for hours.
As root you must edit /etc/pam.d/common-password file and change encryption.
sudo nano /etc/pam.d/common-password
There is a line
password [success=2 default=ignore] pam_unix.so obscure sha512
Change it to
password [success=2 default=ignore] pam_unix.so obscure md5
Now you have to recreate passwords for all accounts that need connection to DB2. This includes instance owner, fenced user, and das user
sudo passwd db2inst1
sudo passwd db2fenc1
sudo passwd dasusr1
After this is done edit /etc/pam.d/common-password file back to use SHA512.