tech.kaotix.dk

First of all. If you don’t know what a SMT-server is you probably don’t need to read any further.

Problem: I was deploying a number of SLES10-SP3 servers in an ESX environment by cloning from a running server – and that all went according to plan. However, when I tried to register the servers to our SMT server the first registration went fine, but the following registrations simply overwrote the previous.

Solution: Google to the rescue!! Rename “deviceid” and “secret” (you could choose to delete them instead if you’re that kind of sys admin – I’m not!) in /etc/zmd and re-run the registration process:

clientSetup4SMT.sh --host <your  SMT server>

On some of the servers I also had to run

suse_register -r

in order to restore the repository list, but on others I had no issues – well, go figure!

I noticed some strange behaviour on some SLES10-SP3 servers I was setting up in a .local domain. I could do a nslookup on the FQDN (<somehostname.local>), no problems there – but when trying to do a

ping <somehost>.local

it failed. I did a bit of searching on the internet and it turns out that SuSE (and as far as I could gather – other Linuxes as well) are haveing difficulties dealing with .local domains. The solution is to add the following to the end of /etc/host.conf

mdns off

And then do a reboot. Voila!

The following one-liner will generate a random eight character string consisting of numbers as well as upper- and  lowercase letters.

echo `< /dev/urandom tr -dc A-Za-z0-9 | head -c8`

or

tr -dc '0-9a-zA-Z' </dev/urandom |head -c8; echo

If you need a shorter or longer password you can ajust the “-c8”-value.

And yes, I know…… a password should contain special characters as well. Please feel free to add a few periods and asterisks

I found this on the net somewhere. I don’t remember where – sorry.

To add a vmdk to a virtaul RHEL5 server, you first of all need to create the vmdk (d’oh!) – I won’t go into that here. Next, on the RHEL5 server do as root:

echo "- - -" > /sys/class/scsi_host/host0/scan (the spaces between the dashed are important)

This will cause the scsi bus to be rescanned and the new disk should be found. For the devicename check “dmesg”. Now you can partition the disk, add it to LVM or whatever.

If you need to force a user to change password at next login, simply use:

# chage -d 0 <userid>

To enable faillog to actually start logging failed login attempts you need to set up PAM to use the module “pam_tally.so”. To configure PAM open the file /etc/pam.d/system-auth in your favourite editor and add the following lines to the file:

auth required pam_tally.so onerr=fail deny=5
account required pam_tally.so

This should make sure that accounts are locked if the number of failed attempts exceeds 5. The counter is reset on successful login.

The behaviour of pam_tally has changed over time – this approach should work on at least Fedora Core 6+, RHEL 5, SLES10 and later.

In SLES 10 the PAM config-file is /etc/pam.d/login

If using Qlogic HBAs in SLES 9, the recommended driver is the vendors own driver. In this case wwn's as well as wwpn's could be found by looking in /proc/scsi/qla2xxx

# cat /proc/scsi/qla2xxx/* | grep node

or

# cat /proc/scsi/qla2xxx/* | grep adapter-port

In SLES 10 the native HBA driver is the recommended. You can find WWNs and WWPNs by looking in /sys/class/fc_host or using the systool

# cat /sys/class/fc_host/host?/node_name

or

# systool -c fc_host -A "node_name"