Add extra disk as /home

Install the disk and then use:

fdisk -l

to check the new device name, if the new disk is not detected try installing scsitools:

apt-get install scsitools

then run:

rescan-scsi-bus

and issue fdisk -l again, supposing your new disk is /dev/sdb use

fdisk /dev/sdb

to create a new partition, press n, then p for a primary partition then enter 1 sinse this will be the only partition on the drive, when it asks you about the first and last cylinders, just use the defaults.
now, to format the newly created partition use:

mkfs.ext4 /dev/sdb1

when done use:

blkid

to check the new partition's uuid and using that edit the /etc/fstab file andding:

UUID=d70d801e-5246-46e2-a7ed-1a95819fd326 /home ext4 errors=remount-ro 0 1

Now mount the new partition on a temporary location with:

mount /dev/sdb1/mnt/

and copy the contents of the current home to the new partition:

cp -r /home/*/mnt/

when done delete all contents from the current home

rm -rf /home/*

unmount the new partiotion

umount /mnt

and remount it under /home

mount /dev/sdb1/home/

Duplicate Oracle Schema

Using imp/exp:
Export the database using:

exp 'system/password' owner=schema_to_be_duplicated file=filename.dmp log=logfile.log

Then import the dump file into the target schema:

imp 'system/password' fromuser=schem_to_be_duplicated touser=target_username file=
filename.dmp

But keep in mind that the target schema must be available on the database. If it does not, then you must have to create it first using CREATE USER command). The import does not create user for you it only migrates objects & data within schemas.

Using impdp/expdp:

We must first create a directory object you can access. The directory object is only a pointer to a physical directory, creating it does not actually create the physical directory on the file system.

sqlplus / AS SYSDBACREATE OR REPLACE DIRECTORY DUMP_DIR AS '/home/oracle/dumpdir/';

Export with:

expdp schema_to_be_duplicated/password DUMPFILE=filename.dmp DIRECTORY=dmpdir

Import with:

impdp REMAP_SCHEMA=schema_to_be_duplicated:new_schema DUMPFILE=filename.dmp DIRECTORY=dmpdir EXCLUDE=JOB

you will be asked for a username and password, the default is system/system

Remember that you must first create the destination user:

CREATE USER new_schema IDENTIFIED BY new_password DEFAULT TABLESPACE users TEMPORARY TABLESPACE temp QUOTA UNLIMITED ON users;
GRANT CREATE session, CREATE table, CREATE view, CREATE procedure, CREATE synonym, CREATE SEQUENCE, CREATE TRIGGER, CREATE TYPE, CREATE MATERIALIZED VIEW, CREATE DATABASE LINK,Debug Any Procedure,Debug Connect Session TO new_schema;
ALTER USER new_schema QUOTA UNLIMITED ON USERS;

CloudStack reset password script

The process to install the password reset script described in the Cloudstack's admin guide was not working for me on an Ubuntu template so I tried to figure what was wrong with it.

In the admin guide they say that we should place the script in /etc/init.d/ and enable it using update-rc.d but that didn't work so I tried to place this in /etc/init/cloudstack.conf

##########################################################################
description "CloudStack password reset"
author "Luis Davim"
# Be sure to block the display managers until our job has completed. This
# is to make sure our kernel services are running before user
# may launch.
start on runlevel [235] or starting gdm or starting kdm or starting prefdm
stop on runlevel [06]
pre-start exec /etc/init.d/cloud-set-guest-password
post-stop exec /etc/init.d/cloud-set-guest-password

That didn't not work either, so I took a look at the script and figured it needed to have the network configured to run.

So I configured my network interface like this:

# The primary network interface
auto eth0
iface eth0 inet dhcp
post-up /etc/init.d/cloud-set-guest-password
pre-down /etc/init.d/cloud-set-guest-password

you can also link the script into the /etc/network/if-up(down) folders:

ln -s /etc/init.d/cloud-set-guest-password/etc/network/if-up/cloud-set-guest-password
ln -s /etc/init.d/cloud-set-guest-password/etc/network/if-down/cloud-set-guest-password

And that was it, now I have an Ubuntu template with a working password reset script.

Note: I've also modified the password script to use chpasswd insted of passwd --stdin since ubuntu does not have the --stdin option in passwd and both ubuntu and centos have chpasswd but that was/is not the problem because usermod with mkpasswd was working...

just replaced:

echo $password | passwd --stdin $user

with

echo "$user:$password" | chpasswd

Linux Transparent bridge

First you need to install the bridge-utils:

apt-get install bridge-utils

Configuring the bridge:

ifconfig eth0 0.0.0.0 promisc up
ifconfig eth1 0.0.0.0 promisc up
brctl addbr br0
brctl addif br0 eth0
brctl addif br0 eth1
ifconfig br0 1.2.3.4 netmask 255.255.255.0 up
route add default gw 1.2.3.4 dev br0

In this example, I suppose you are using eth0 and eth1. In the ifconfig line, I assigned IP address 1.2.3.4 to the bridge so I can access it remotely. Use an IP address in your network.
You may check that the bridge is working by using tcpdump:

# tcpdump -n -i eth0
...
(lots of funny stuff)
...
# tcpdump -n -i eth1
...
(lots of funny stuff)
...

Plug your machine into the network, and everything should work. Your Linux box is now a big, expensive two-port switch.

Making the Bridge Permanent

Edit the file /etc/network/interfaces and add:

auto br0
iface br0 inet dhcp
bridge_ports eth1 eth2
bridge_stp on

CloudStack LDAP

References:

• http://docs.cloudstack.org/CloudStack_Documentation/Design_Documents/LDAP_Authentication
• http://docs.cloudstack.org/CloudStack_Documentation/Developer's_Guide%3A_CloudStack

First you need to configure LDAP by making an API call with an URL like this:

http://127.0.0.1:8096/client/api?command=ldapConfig&hostname=127.0.0.1&searchbase=ou%3Dpeople%2Co%3DsevenSeas&queryfilter=%28%26%28uid%3D%25u%29%29&binddn=%20cn%3DJohn+Fryer%2Cou%3Dpeople%2Co%3DsevenSeas&bindpass=secret&port=10389&response=json

Or in a more readable format:

http://127.0.0.1:8096/client/api?command=ldapConfig
&hostname=127.0.0.1
&searchbase=ou%3Dpeople%2Co%3DsevenSeas
&queryfilter=%28%26%28uid%3D%25u%29%29
&binddn=%20cn%3DJohn+Fryer%2Cou%3Dpeople%2Co%3DsevenSeas
&bindpass=secret
&port=10389
&response=json

Note the URL encoded values, here you have the decoded version:

http://127.0.0.1:8096/client/api?command=ldapConfig
&hostname=127.0.0.1
&searchbase=ou=people,o=sevenSeas
&queryfilter=(&(uid=%u))
&binddn= cn=John Fryer,ou=people,o=sevenSeas
&bindpass=secret
&port=10389
&response=json

You can use this link to encode/decode your url -> http://meyerweb.com/eric/tools/dencoder/

After you've created your URL (with encoded values) open your browser, login into cloudstack and then fire up your ldap config URL.
Now if you go back to cloudstack and under "Global Settings" search for LDAP and you should see that LDAP is configured.

Now you have to manually create the user accounts with the same logins as in your LDAP server or you can use the CloudStack API to make a script and "sync" your LDAP users into CloudStack, I've written a PHP script that does this.
You'll have to modify it to match your LDAP schema and you can get it after the break.

How to reset lost user password on a Linux Machine

First you’ll want to make sure to choose the regular boot kernel that you use (typically just the default one), and then use the “e” key to choose to edit that boot option.

Now just hit the down arrow key over to the “kernel” option, and then use the “e” key to switch to edit mode for the kernel option.

Note: if the grub menu does not show up try hitting the Shift or the Space keys right after the bios screen.

You’ll want to remove the “ro quiet splash” part with the backspace key, and then add this onto the end:

rw init=/bin/bash

Press F10 or ctrl+x to boot with that option.

At this point the system should boot up very quickly to a command prompt.

Now you can use the passwd command to change the password.

passwd username

where username is the username you want to reset.
After changing your password, use the following commands to reboot your system. (The sync command makes sure to write out data to the disk before rebooting)

sync
reboot –f

I found that the –f parameter was necessary to get the reboot command to work for some reason. You could always hardware reset instead, but make sure to use the sync command first.

NOTE for VMWare users:

Probably you wont ever see the boot menu on a VM because it will boot to fast, to work around this you can set up the vm to delay the bios for a few seconds:

bios.bootDelay = "15000"

This causes the bios to delay for 15 seconds so you can press keys, you can set it in the VM .vmx file or using vSphere under the vm settings, on the options tab, boot options.

Then just start the VM and press esc on the grub loading message and follow the steps described above.

Increase LVM Volume

This is how I did it on a VMWare Machine but the procedure should be the same for a phisical machine:

First off, VMWare, like many other hypervisors, allows to create a second HDD on the fly while the vm is running.

Once that was done, login into the server and:

# echo “- – -” > /sys/class/scsi_host/host#/scan

partprobe should also do the trick

Just to see that the new disk is available use:

# fdisk -l

In this case it was /dev/sdb

create a new partition with

# fdisk /dev/sdb

press n and then w

Format the new partition:

# mkfs.ext3 /dev/sdb1

list the volume groups:

# vgs

add new physical volume

# pvcreate /dev/sdb1

extend the default volume group from the vgs command

# vgextend VolGroup /dev/sdb1

check to see pv and vg has another volume with:

# vgs

And list logical volumes

# lvdisplay

extend my / volume by the entire size of /dev/sdb1

# lvextend /dev/VolGroup/lv_root/dev/sdb1

resize filesystem to match vol size increase

# resize2fs /dev/VolGroup/lv_root

(requires a 2.6 kernel to resize while fs running)