Ajitabh Pandey's Soul & Syntax

Exploring systems, souls, and stories – one post at a time

Author: Ajitabh

  • Ansible Quirks – 1

    I started on the ansible learning path about 6 months or so back and have been writing my roles for deploying / configuring various systems I manage. Today while writing a template for sshd_config, I came across a point wherein the handler failed to restart the SSH service on the target server. Fortunately I was logged in as sudo on one of the terminals, and then I checked the config file generated and pushed by ansible. I found that the line

    PermitRootLogin {{ permit_root_login }}

    was translated to

    PermitRootLogin True

    . For a while I though that the variable I defined in

    defaults/main.yml

    was wrongly having a value of True instead of Yes, but I was wrong. Looking into some of the bugs filed in ansible I realised that this is the expected behaviour. The way to prevent strings like yes/no and true/false to be converted to True/False they have to be preceded with !!str in the variable definition. So the variable definition in my case would look like –

    permit_root_login: !!str Yes

  • OSX Screenshots tips

    Changing location to store screenshot

    The default place where screenshots are saved in OSX is the Desktop. For people (like me), who would like to keep their desktops nice and clean and a little organised, we can change the location where the screenshot are stored. This needs command line. Launch “Terminal” and type the following commands which should do the trick. I am moving my screenshot location to somewhere in Google Drive. Please note that the location which you are setting as the target for storing screenshots, must exist, and as you can see, I am creating it first.

    $ mkdir -p ~/Google\ Drive/Pictures/Screenshots
$ defaults write com.apple.screencapture location ~/Google\ Drive/Pictures/Screenshots/ && killall SystemUIServer

    The “killall” command is used to restart the SystemUIServer so that the changes can be picked up by the system.

    Changing the Screenshot file type

    The default screenshot file type is PNG. However, you can change this to – jpg, tiff, pdf, gif by using the following command on the terminal.

    $ defaults write com.apple.screencapture type gif && killall SystemUIServer

  • Huawei E303c as Modem on Raspberry Pi

    I have a Huawei E303c USB modem, which I wanted to use with my Raspberry Pi so that I can connect my Pi to the Internet and run my local server. Now why would I want to do that when I have a broadband at home? Now those of you who are in India and uses ACT Broadband, which has recently become very popular in Southern India due to its fibre technology, may know that ACT uses Carrier-Grade NAT, as a result of which I do not have the public IP address and hence can not rely on port forwarding on my router.

    Here is how I configured the device. During this course, I referred to various other websites and at the bottom of this page, I have provided those as a reference.

    These UMTS modems consume a lot of power and hence it is recommended that these may be connected to a powered USB hub connected to the Pi.

    Configuring the USB Modem Device

    Connect the device to the USB port and issue the lsusb command after few seconds to check if the device has been detected –

    $ lsusb
Bus 001 Device 008: ID 12d1:14fe Huawei Technologies Co., Ltd.

    Note down the device number, in this case 12d1:14fe
    If you see the dmesg at this point you will find that the device will be detected as a CDROM and a USB storage device and not a modem. I do not have the output as I forget to save it.

    We need to install usb-modeswitch package which helps in the switching of device mode from USB Storage to USB modem mode.

    $ sudo apt-get install usb-modeswitch
$ sudo reboot
$ lsusb
Bus 001 Device 008: ID 12d1:1506 Huawei Technologies Co., Ltd. E398 LTE/UMTS/GSM Modem/Networkcard

    Make a note of the device number for future reference, we would need this number for TargetProduct value. In this case this is 12d1:1506. If you see this has been changed from the last time. Here the usb-modeswitch is active. The pi has detected my E303C as E398 but that’s alright.

    Now running dmesg will show the below which indicates that the modem is detected and configured –

    $ sudo dmesg | grep -i usb
[ 0.593089] usbcore: registered new interface driver usbfs
[ 0.598824] usbcore: registered new interface driver hub
[ 0.604340] usbcore: registered new device driver usb
[ 1.015352] usbcore: registered new interface driver smsc95xx
[ 1.539943] dwc_otg 20980000.usb: DWC OTG Controller
[ 1.546616] dwc_otg 20980000.usb: new USB bus registered, assigned bus number 1
[ 1.555602] dwc_otg 20980000.usb: irq 32, io mem 0x00000000
[ 1.573463] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[ 1.581919] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 1.590782] usb usb1: Product: DWC OTG Controller
[ 1.597093] usb usb1: Manufacturer: Linux 4.1.18+ dwc_otg_hcd
[ 1.604400] usb usb1: SerialNumber: 20980000.usb
[ 1.611639] hub 1-0:1.0: USB hub found
[ 1.623853] usbcore: registered new interface driver usb-storage
[ 1.797393] usbcore: registered new interface driver usbhid
[ 1.804559] usbhid: USB HID core driver
[ 2.076207] usb 1-1: new high-speed USB device number 2 using dwc_otg
[ 2.316814] usb 1-1: New USB device found, idVendor=0424, idProduct=9512
[ 2.325540] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 2.338687] hub 1-1:1.0: USB hub found
[ 2.626257] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
[ 2.736724] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00
[ 2.745604] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 2.844813] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-20980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:c2:b6:99
[ 2.956388] usb 1-1.2: new high-speed USB device number 4 using dwc_otg
[ 3.086999] usb 1-1.2: New USB device found, idVendor=1a40, idProduct=0201
[ 3.095927] usb 1-1.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ 3.105228] usb 1-1.2: Product: USB 2.0 Hub [MTT]
[ 3.114467] hub 1-1.2:1.0: USB hub found
[ 3.416291] usb 1-1.2.3: new high-speed USB device number 5 using dwc_otg
[ 3.527702] usb 1-1.2.3: New USB device found, idVendor=1058, idProduct=0748
[ 3.536728] usb 1-1.2.3: New USB device strings: Mfr=1, Product=2, SerialNumber=5
[ 3.547663] usb 1-1.2.3: Product: My Passport 0748
[ 3.554208] usb 1-1.2.3: Manufacturer: Western Digital
[ 3.561146] usb 1-1.2.3: SerialNumber: 57585331453233574A4C4432
[ 3.617837] usb-storage 1-1.2.3:1.0: USB Mass Storage device detected
[ 3.628629] scsi host0: usb-storage 1-1.2.3:1.0
[ 3.716364] usb 1-1.2.4: new high-speed USB device number 6 using dwc_otg
[ 3.837768] usb 1-1.2.4: New USB device found, idVendor=1058, idProduct=0702
[ 3.846795] usb 1-1.2.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3.857730] usb 1-1.2.4: Product: External HDD
[ 3.864239] usb 1-1.2.4: Manufacturer: Western Digital
[ 3.871169] usb 1-1.2.4: SerialNumber: 575843393037323139333433
[ 3.924643] usb-storage 1-1.2.4:1.0: USB Mass Storage device detected
[ 3.946315] scsi host1: usb-storage 1-1.2.4:1.0
[ 4.037283] usb 1-1.2.5: new high-speed USB device number 7 using dwc_otg
[ 4.159220] usb 1-1.2.5: New USB device found, idVendor=12d1, idProduct=1506
[ 4.168316] usb 1-1.2.5: New USB device strings: Mfr=3, Product=2, SerialNumber=0
[ 4.179397] usb 1-1.2.5: Product: HUAWEI Mobile
[ 4.185712] usb 1-1.2.5: Manufacturer: HUAWEI
[ 4.256197] usb-storage 1-1.2.5:1.4: USB Mass Storage device detected
[ 4.282053] scsi host2: usb-storage 1-1.2.5:1.4
[ 4.307321] usb-storage 1-1.2.5:1.5: USB Mass Storage device detected
[ 4.329879] scsi host3: usb-storage 1-1.2.5:1.5
[ 4.843019] usbcore: registered new interface driver cdc_ncm
[ 4.868289] usbcore: registered new interface driver usbserial
[ 4.966542] usbcore: registered new interface driver usbserial_generic
[ 4.975231] usbserial: USB Serial support registered for generic
[ 5.048437] usbcore: registered new interface driver cdc_wdm
[ 5.209021] usbcore: registered new interface driver option
[ 5.342683] usbserial: USB Serial support registered for GSM modem (1-port)
[ 5.546749] huawei_cdc_ncm 1-1.2.5:1.1: cdc-wdm0: USB WDM device
[ 5.555830] huawei_cdc_ncm 1-1.2.5:1.1 wwan0: register 'huawei_cdc_ncm' at usb-20980000.usb-1.2.5, Huawei CDC NCM device, 58:2c:80:13:92:63
[ 5.741270] usbcore: registered new interface driver huawei_cdc_ncm
[ 5.839357] usb 1-1.2.5: GSM modem (1-port) converter now attached to ttyUSB0
[ 5.995187] usb 1-1.2.5: GSM modem (1-port) converter now attached to ttyUSB1
[ 6.225904] usb 1-1.2.5: GSM modem (1-port) converter now attached to ttyUSB2

    Now we will look for the relevant device configurations in the sample config files which comes with the usb-modeswitch package and extract the file.

    $ tar -tvzf /usr/share/usb_modeswitch/configPack.tar.gz|grep "12d1:14fe"
-rw-r--r-- root/root       155 2012-12-08 22:22 12d1:14fe
$ tar -xvzf /usr/share/usb_modeswitch/configPack.tar.gz 12d1\:14fe
12d1:14fe
$ ls -l 12d1\:14fe
-rw-r--r-- 1 ajitabhp ajitabhp 155 Dec  8  2012 12d1:14fe

    Checking the contents of this file will give me

    $ cat 12d1\:14fe 
# T-Mobile NL (Huawei E352)

TargetVendor=  0x12d1
TargetProduct= 0x1506

MessageContent="55534243123456780000000000000011062000000100000000000000000000"

    If you notice that the TargetProduct value of 0x1506 matches with the value we found earlier in the lsusb output after the reboot. Based on the contents of this file, we will now create a configuration file for the usb_modeswitch utility.

    $ sudo vi /etc/usb_modeswitch.d/12d1\:14fe

# Huawei E303C 3G USB modem
# usb_modeswitch configuration
#
DefaultVendor=0x12d1
DefaultProduct=0x14fe

TargetVendor=0x12d1
TargetProduct=0x1506

MessageContent="55534243123456780000000000000011062000000100000000000000000000"

    Configuring the Dialer

    I will use wvdial utility for dialing out to the internet –

    $ sudo apt-get install wvdial
$ sudo vi /etc/wvdial.conf
[Dialer Default]
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Modem Type = Analog Modem
Baud = 460800
New PPPD = yes
Modem = /dev/ttyUSB0
ISDN = 0

[Dialer t24]
Modem Type = Analog Modem
Modem = /dev/ttyUSB0
ISDN = 0
Stupid Mode = 1
New PPPD = yes
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2
Init3 = AT+CGDCONT=1, "IP", "T24.Internet"
Phone = *99#
Username = xxxxxxxxxx
Password = xxxxxxxxxx

[Dialer tatadocomo]
Modem Type = Analog Modem
Modem = /dev/ttyUSB0
ISDN = 0
Stupid Mode = 1
New PPPD = yes
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2
#Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Baud = 115200
Phone = *99#
Username = internet
Password = internet

    The xxxxxxxxxx in one of the configurations above is my 10 digit mobile number for the SIM. I tried this with two different SIMs, hence you are seeing two entries. T24 in India is a rebranded Tata Docomo mobile service provider.

    Now connect to internet with one of the following (depending on which SIM has been connected –

    $ wvdial t24

    or

    $wvdial tatadocomo

    If you remove the USB dongle and then reconnect it, you may have to do the following in order to bring the device in the modem mode –

    $ sudo usb_modeswitch -c /etc/usb_modeswitch.d/12d1\:14fe

    Resources

  • Installing Oracle Instant Client for Mac OSX

    I came across few links for installing Oracle Instant Client on Mac OS X namely – this and this. But I don’t like to tinker with the System paths while installing any s/w manually. I did the same with perl CPAN modules, I install them locally in home directory and same with Python pip packages, but that’s another post for future. So I had to work out the following method for installing the Oracle Instant Client as I needed sqlplus client for connecting to my RDS Oracle instance.

    Download the following two files from http://www.oracle.com/technetwork/topics/intel-macsoft-096467.html

    instantclient-basic-macos.x64-11.2.0.4.0.zip
instantclient-sqlplus-macos.x64-11.2.0.4.0.zip

    These will be downloaded in the Downloads directory

    Unzip these two files in a single directory

    $ cd Downloads
$ unzip instantclient-sqlplus-macos.x64-11.2.0.4.0.zip
$ unzip instantclient-basic-macos.x64-11.2.0.4.0.zip
$ cd ~

    Create the required structure in the home directory and copy the files in place

    $ mkdir -p oracle/product/instantclient_64/11.2.0.4.0/{bin,lib,jdbc/lib,rdbms/jlib,sqlplus/admin,network/admin}
$ mv Downloads/instantclient_11_2/ojdbc* product/instantclient_64/11.2.0.4.0/jdbc/lib/
$ mv Downloads/instantclient_11_2/x*.jar product/instantclient_64/11.2.0.4.0/rdbms/jlib/
$ mv Downloads/instantclient_11_2/glogin.sql product/instantclient_64/11.2.0.4.0/sqlplus/admin/
$ mv Downloads/instantclient_11_2/*dylib* product/instantclient_64/11.2.0.4.0/lib/
$ mv Downloads/instantclient_11_2/*README product/instantclient_64/11.2.0.4.0/
$ mv Downloads/instantclient_11_2/adrci instantclient_11_2/genezi instantclient_11_2/sqlplus instantclient_11_2/uidrvci product/instantclient_64/11.2.0.4.0/bin/

    Make the following additions to your ~/.bashrc file –

    ORACLE_HOME="~/oracle/product/instantclient_64/11.2.0.4.0"
PATH=$ORACLE_HOME/bin:$PATH
alias sqlplus="DYLD_LIBRARY_PATH=$ORACLE_HOME/lib sqlplus"

    Now I can connect to the Oracle RDS instance using –

    $ sqlplus 'root@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=ajitabh-oracle-test.bkl9a9lqwsoxcd.us-west-1.rds.amazonaws.com)(PORT=1521))(CONNECT_DATA=(SID=ORCL)))'

SQL*Plus: Release 11.2.0.4.0 Production on Wed Aug 26 21:59:46 2015

Copyright (c) 1982, 2013, Oracle. All rights reserved.

Enter password:

Connected to:
Oracle Database 11g Release 11.2.0.4.0 - 64bit Production

SQL>

    That’s it. More on exploring Oracle RDS later.

  • Expanding HardDisk of VirtualBox Guest

    VirtualBox is a beautiful piece of virtualisation software created for users, first acquired by Sun and then by Oracle as a part of Sun acquisition. I have been using VirtualBox for quite a few testing projects, however until today have never needed to expand my hard drive on a guest. I am running a Windows 7 guest for some client side related tests. I started with a 25Gb disk for Windows 7, but after applying all security patches (I like my machines patched and upto-date), I realised that 25GB is all gone.

    This is where I love virtualisation. I do not need to buy a new disk if I need more space on my virtual machine (as far as my physical disk has enough space). I can just expand the existing virtual hard disk and get all the space I need. VirtualBox does not yet have a GUI option to do storage expansion work, but fortunately VirtualBox comes with an excellent command line, so I followed the following steps in order to increase my hard drive space.

    In order to see the virtual hard disk info, following command can be used.

    $ VBoxManage showhdinfo VirtualBox\ VMs/Win764/Win764.vdi
UUID: e2272600-df31-4dbc-a71d-56af5f5714df
Parent UUID: base
State: created
Type: normal (base)
Location: /Users/ajitabhp/VirtualBox VMs/Win764/Win764.vdi
Storage format: VDI
Format variant: dynamic default
Capacity: 25600 MBytes
Size on disk: 25502 MBytes
In use by VMs: Win764 (UUID: 1beda97f-4222-49ad-993e-342e1d44e288)

    To expand this to 50GB and then verify that the operation is done

    $ VBoxManage modifyhd --resize 50000 VirtualBox\ VMs/Win764/Win764.vdi
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
$ VBoxManage showhdinfo VirtualBox\ VMs/Win764/Win764.vdi
UUID:           e2272600-df31-4dbc-a71d-56af5f5714df
Parent UUID:    base
State:          created
Type:           normal (base)
Location:       /Users/ajitabhp/VirtualBox VMs/Win764/Win764.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       50000 MBytes
Size on disk:   25502 MBytes
In use by VMs:  Win764 (UUID: 1beda97f-4222-49ad-993e-342e1d44e288)

    Now so far we have only been able to expand the Hard disk drive, but the partition table still would say that the NTFS filesystem is still the original size. However, we can not use Windows to expand the partition table of the same partition wherein it is installed. The System Rescue CD came to help here. I attached the System Rescue CD ISO to the windows virtual machine and booted the system.

    In the command prompt, I used the GNU parted to expand the partition table (partition 2 in my case)

    % parted resizepart 2 50GB /dev/sda

    In case you want to check which is your NTFS partition, which you want to expand use the following command –

    % parted print /dev/sda

    After expanding the partition table, we need to expand the NTFS filesystem on it, which can be done by ntfsresize utility as below. First I ran the utility in info mode to find out the exact size to which to expand to and then in dry run (test) mode and finally actually ran it.

    % ntfsresize --info /dev/sda2
% ntfsresize -n -s 52294093824 /dev/sda2
% ntfsresize -s 52294093824 /dev/sda2

    Finally remove the the System Rescue CD ISO file and boot the system normally in windows, a check will be force and you are done.