Showing posts with label Debug. Show all posts
Showing posts with label Debug. Show all posts

Friday, 24 August 2018

Does RHEL 7 support online resize of disk partitions?

Environment

  • Red Hat Enterprise Linux 7

Issue

  • Both Xen and KVM support online resize of the virtual block devices that the virtual machines use.
  • Unfortunately, since the partitions in the boot virtual block device are already in use, those can't be modified online and the virtual machine won't pick up the changes on the boot virtual block device without a reboot.
  • We are looking for ability to dynamically increase a partitioned volume, is it possible to resize the disk partitions online in RHEL 7?
  • We are unable to dynamically increase a SAN attached volume without taking the volume offline. When will this feature to Support online resize of disk partitions be available?

Resolution

The ability to resize a Logical Volume and filesystem has long been provided by Logical Volume Manager (LVM) by simply using the entire block device (/dev/sdx for example) as a Physical Volume in the LVM Volume Group. There is no need for the old style of partition. This would allow the Logical Volume and filesystem to easily be expanded.
As to older style partitions, this feature has been added in RHEL 7 current release with a feature request (RFE has been filed to add support for online resize of disk partitions to RHEL 7 in private Red Hat Bugzilla 853105). With this feature, it's possible to resize the disk partitions online in RHEL 7.

Warning: Online partition table resizing is not a recommended process mostly because the underlying layer of an active logical volume or filesystem that relies on that information is being modified. While it is possible to perform online partition resize operation, it is not recommended simply from a data integrity standpoint and not because it's not possible.

  • In order to resize online a partition which is in use please observe the following steps:
# fdisk -l /dev/vda

Disk /dev/vda: 32.2 GB, 32212254720 bytes, 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000db7e6

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048     1026047      512000   83  Linux
/dev/vda2         1026048    28289023    13631488   8e  Linux LVM

# cat /proc/partitions 
major minor  #blocks  name

 252        0   31457280 vda
 252        1     512000 vda1
 252        2   13631488 vda2
  11        0    1048575 sr0
 253        0   10240000 dm-0
 253        1    2129920 dm-1

# pvs
  PV         VG          Fmt  Attr PSize  PFree
  /dev/vda2  rhel_vm-205 lvm2 a--  13.00g 1.20g
  • Modify the on-disk partition table as usual (e.g. by using fdisk command).
    • Delete the partition:
      Command (m for help): d
      Partition number (1,2, default 2): 2
      Partition 2 is deleted
      
    • Re-create the partition with the new size:
      Command (m for help): n
      Partition type:
         p   primary (1 primary, 0 extended, 3 free)
         e   extended
      Select (default p): p
      Partition number (2-4, default 2): 2
      First sector (1026048-62914559, default 1026048): 
      Using default value 1026048
      Last sector, +sectors or +size{K,M,G} (1026048-62914559, default 62914559): +18G
      Partition 2 of type Linux and of size 18 GiB is set
      
      Command (m for help): t
      Partition number (1,2, default 2): 2
      Hex code (type L to list all codes): 8e
      Changed type of partition 'Linux' to 'Linux LVM'
      
      Command (m for help): p
      
      Disk /dev/vda: 32.2 GB, 32212254720 bytes, 62914560 sectors
      Units = sectors of 1 * 512 = 512 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk label type: dos
      Disk identifier: 0x000db7e6
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/vda1   *        2048     1026047      512000   83  Linux
      /dev/vda2         1026048    38774783    18874368   8e  Linux LVM
      
    • Commit changes to on-disk partition table:
      Command (m for help): w
      The partition table has been altered!
      
      Calling ioctl() to re-read partition table.
      
      WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
      The kernel still uses the old table. The new table will be used at
      the next reboot or after you run partprobe(8) or kpartx(8)
      Syncing disks.
      
    • While on-disk partition table has been updated, observe that on-memory kernel partition table has not:
      # partprobe 
      Error: Partition(s) 2 on /dev/vda have been written, but we have been unable to inform the kernel of the change, probably because it/they are in use.  As a result, the old partition(s) will remain in use.  You should reboot now before making further changes.
      
      # cat /proc/partitions | grep vd
       252        0   31457280 vda
       252        1     512000 vda1
       252        2   13631488 vda2
      
  • Execute partx (provided by util-linux package) with --update option on the block device to update the in-memory kernel partition table from the on-disk partition table:
    # partx -u /dev/vda
    
  • Verify that in-memory kernel partition table has been updated with the new size:
    # cat /proc/partitions | grep vd
     252        0   31457280 vda
     252        1     512000 vda1
     252        2   18874368 vda2
    
  • Proceed with any further steps, in this example by extending the PV on the partition:
    # pvresize /dev/vda2
      Physical volume "/dev/vda2" changed
      1 physical volume(s) resized / 0 physical volume(s) not resized
    
    # pvs
      PV         VG          Fmt  Attr PSize  PFree
      /dev/vda2  rhel_vm-205 lvm2 a--  18.00g 6.20g
    

Root Cause

  • Changes to allow online resizing of in-use partitions are required in both kernel and userland.
    • RHEL7 kernels include the required changes to BLKPG ioctl from block: add partition resize function to blkpg ioctl to support BLKPG_RESIZE_PARTITION operation.
    • RHEL7 util-linux package includes partx and resizepart binaries, currently the only userland commands that support BLKPG_RESIZE_PARTITION operation of BLKPG ioctl.

Friday, 28 July 2017

Reset Your Forgotten Ubuntu Password in 2 Minutes or Less





If you’ve ever forgotten your password, you aren’t alone… it’s probably one of the most common tech support problems I’ve encountered over the years. Luckily if you are using Ubuntu they made it incredibly easy to reset your password.
image
All it takes is adjusting the boot parameters slightly and typing a command or two, but we’ll walk you through it.
Reset Your Ubuntu Password
Reboot your computer, and then as soon as you see the GRUB Loading screen, make sure to hit the ESC key so that you can get to the menu.
image
Root Shell – Easy Method
If you have the option, you can choose the “recovery mode” item on the menu, usually found right below your default kernel option.
image[3]
Then choose “Drop to root shell prompt” from this menu.
image[6]
This should give you a root shell prompt.
Alternate Root Shell Method
If you don’t have the recovery mode option, this is the alternate way to manually edit the grub options to allow for a root shell.
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.
image
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.
image
You’ll first be presented with a screen that looks very similar to this one:
image
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
image
Once you hit enter after adjusting the kernel line, you’ll need to use the B key to choose to boot with that option.
image
At this point the system should boot up very quickly to a command prompt.
Changing the Actual Password
You can use the following command to reset your password:
passwd <username>
For example my username being geek I used this command:
passwd geek
image
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.
And now you should be able to login without any issues.

Wednesday, 10 July 2013

Manually uninstalling VMware Workstation from Linux hosts

Manually uninstalling VMware Workstation from Linux

VMWare Workstation doesn't ship in a deb, so it isn't registered in dpkg (which is why you can't find it in the software center). It does have an install and uninstall utility though.

To uninstall VMWare Workstation, you will need to run


#vmware-installer --uninstall-product vmware-workstation

Details

This article provides steps for manually removing VMware Workstation when the uninstaller script or RPM package fails to remove the product automatically.

Solution

Note: Log into the host using the root account to execute the terminal commands in this article. If running Ubuntu, the root account is not available by default. Prepend all commands with sudo,or switch to root using this command:

sudo su -

Warning: This command provides unrestricted access to the operating system. It is possible to cause damage to the system when using this access level.

  1. Open a command prompt. For more information, see Opening a command or shell prompt (1003892). Type the commands as indicated in the steps of this procedure.
  2. Shut down all VMware applications and services.

    /etc/init.d/vmware stop

  3. Verify that all processes have stopped:

    lsmod | grep vm

    Note: A zero must be listed beside VMware related modules to indicate that they are no longer running.

  4. Move the VMware libraries to the /tmp directory:

    cd /lib/modules/kernel_version/misc
    mv vm* /tmp


    Note: If the kernel has ever been updated, you must check and move the files from multiple paths. Substitute the kernel version where indicated above.

  5. Unload the kernel modules:

    rmmod vmnet.o
    rmmod vmmon.o
    rmmod vmci.o
    rmmod vmblock.o
    rmmod vmppuser.o


  6. Remove the VMware startup scripts:

    RedHat and Most Distributions:
    rm /etc/rc.d/init.d/rc2.d/*vmware*
    rm /etc/rc.d/init.d/rc3.d/*vmware*
    rm /etc/rc.d/init.d/rc5.d/*vmware*
    rm /etc/rc.d/init.d/rc6.d/*vmware*


    Ubuntu:

    rm /etc/rc2.d/*vmware*
    rm /etc/rc3.d/*vmware*
    rm /etc/rc5.d/*vmware*
    rm /etc/rc6.d/*vmware*


    Note: If you are using a different Linux distribution, substitute the correct path in the commands.

  7. Remove the remaining VMware files and directories:

    rm -rf /etc/vmware*
    rm /usr/bin/vmware-usbarbitrator
    rm /usr/bin/vmnet*
    rm -r /usr/lib/vmware*
    rm -r /usr/share/doc/vmware*


  8. If an RPM package was used to install the VMware product, complete these steps to delete the RPM database entry:

    rpm -qa | grep VMware

    A list of VMware packages is presented. Copy the exact package name for the next step and paste it into the command where indicated.

  9. Remove the VMware packages:

    rpm --erase --nodeps VMware_Package_Name

Thursday, 16 May 2013

Update script working with Backtrack 5

I could not find an update script working with Backtrack 5 so I decided to make a quick one.

Updated version: 2.0

Changelog Version 2.0
Code:
* Reviewed all tools.
* Compatible with Backtrack 5 R2/R3.
* Removed the menu.
Code:
git clone git://github.com/sickn3ss/backtrack_update.git
cd backtrack_update
chmod a+x backtrack5_update.py
./backtrack5_update.py
Screenshot:



If you know more tools I could add to the script in order to update them please feel free to post them here.
Also if you find any bugs or have any feedback feel free to contact me in this thread. I will update the thread with each update to the script.

NOTE: Please make sure you understand what the script does before running it.

Enjoy!

Tuesday, 8 January 2013

Got files separed from norm HTML

After meet up with team members we decide to migrate the site from norm HTML to PHP, the all projetc will take quite a while to finish, but so far the foundations, of the project are already laid down.. Quite interesting to see how this process is unfolding down ...




  • Cut all the code and past in a separated document
  • Save the new document with a different header name with .php file extension.
  • Then import the content of the heading document into the main html document using the include* function - [ include is part of php library ]
Seems like all gone as we were expecting, but bear in mind that we faced some bugs when we tried to apply this approach the first time  ... Here it goes the output still getting the original content but keeping all the information rendered on server..


Here follows a screen shoot of the file the way it was before it been changed .. All the HTML markup in just one page ..




Thursday, 13 December 2012

Using Virtual Ethernet Adapters in Promiscuous Mode on a Linux Host


VMware Workstation does not allow the virtual Ethernet adapter to go into promiscuous mode unless the user running VMware Workstation has permission to make that setting. This follows the standard Linux practice that only root can put a network interface into promiscuous mode.

When you install and configure VMware Workstation, you must run the installation as root. VMware Workstation creates the VMnet devices with root ownership and root group ownership, which means that only root has read and write permissions to the devices.

To set the virtual machine's Ethernet adapter to promiscuous mode, you must launch VMware Workstation as root because you must have read and write access to the VMnet device. For example, if you are using bridged networking, you must have access to /dev/vmnet0.

To grant selected other users read and write access to the VMnet device, you can create a new group, add the appropriate users to the group and grant that group read and write access to the appropriate device. You must make these changes on the host operating system as root (su -). For example, you can enter the following commands:

chgrp <newgroup> /dev/vmnet0

chmod g+rw /dev/vmnet0

<newgroup> is the group that should have the ability to set vmnet0 to promiscuous mode.
The command to run vmware workstations ads root is simple: user@user#:~$ sudo vmware start

If you want all users to be able to set the virtual Ethernet adapter (/dev/vmnet0 in our example) to promiscuous mode, run the following command on the host operating system as root:

chmod a+rw /dev/vmnet0


This is another posting showing "how to do computing" for everyday computer usages... For a general public

VMware on Linux : Running in Permiscuous Mode


 VMware on Linux: Promiscuous Mode

When VMware Workstation is hosted under Linux, by default it doesn't allow VM Guests to access the network in Promiscuous mode.  There's an easy fix for this...

If you run something like Wireshark from a VM Guest, you'll see VMware display an error message.

The problem lies with the permissions on the Host.  When VMware is started without root privileges, it doesn't have the permissions necessary to access the /dev/vmnet0 device.

A quick temporary bodge is to use chgrp and chmod on the Host, to tweak the permissions on /dev/vmnet* until the next reboot (where yourgroup is a group that your user account is in - typically admin on my Ubuntu machines):
   chgrp yourgroup /dev/vmnet*
   chmod g+rw /dev/vmnet*

A more permanent fix is to edit /etc/init.d/vmware on the Host, and tweak the ownership and permissions when the device is created, by adding the lines in red:
  # Start the virtual ethernet kernel service
   vmwareStartVmnet() {
      vmwareLoadModule $vnet
      "$BINDIR"/vmware-networks --start >> $VNETLIB_LOG 2>&1
      chgrp yourgroup  /dev/vmnet*
      chmod g+rw /dev/vmnet*

After you restart the Host's VMware daemon ...

   /etc/init.d/vmware stop
   /etc/init.d/vmware start

you'll be able to boot your Guest VM, and use Wireshark or whatever in the Guest.  Just Remember!   Your VM Guest's Network Adapter must be set to BRIDGED (connected directly to the physical network), not NAT (used to share the host's IP address).

Aside: I did think it ought be possible to achieve the same effect a little more cleanly, by creating a file in /etc/udev/rules.d to set the desired ownership and permission modes for /dev/vmnet*.  But nothing I've tried has worked.  Anyone?

Friday, 12 October 2012

md5sum.exe introduction


After you download all the Shorten (.shn) files for a particular disc or show, you want to verify that the files are not corrupted or otherwise unusable before you burn them to disc or host them on your file server. We do this by checking the downloaded Shorten (.shn) files against an .md5 file. An .md5 is a simple text file that contains a "fingerprint" of each Shorten file.


When you perform an md5 check, you are comparing the fingerprint from the files you downloaded to the fingerprint of the files on the server you downloaded from. If the md5's (fingerprints) match, you have an uncorrupted Shorten file.



 md5sum.exe - 48KB         88170 Downloads since 9/29/00



  • Windows 95/98/Me: Download md5sum.exe to c:\windows\command

  • Windows NT/2000: Download md5sum.exe to your c:\winnt\system32
  •  

    Open an MS-DOS window and go to the directory of the show you want to check. When you are in that directory, type:
    md5sum -c [filename].md5
     
    You must insert the name of the .md5 file [without the brackets]. Below is an example of a successful md5sum check:
     
     
    On the other hand, if a track does not pass the md5check, you will see the following:
    If any Shorten files do not pass the .md5 check, you should delete the offending file(s), and try re-downloading. Then run the .md5 check again. The file(s) should now pass the .md5 check.

    If the same files fail an .md5 check more than twice, you should contact the FTP Siteop you downloaded the files from and let them know what tracks are giving you a problem. They may be hosting a corrupted track without knowing it.

    Open an MS-DOS window and go to the directory of the show you want to create an .md5 file for. When you are in that directory, type:

    md5sum *.shn > [filename].md5
     
    NOTE: You must insert the name of the .md5 file [without the brackets]. Example:
     
    md5sum *.shn > ph94-06-26d1.md5

    An .md5 file will be created and placed in that directory. Please remember to adhere the etree.org naming scheme when naming .md5 files!

    Please remember to always .md5 check your Shorten files before burning!
      

    Special thanks to bruce@gridpoint.com and the PCP community for compiling this special version of md5sum. Documentation and graphics by Mike Wren.


     

    Thursday, 15 March 2012

    One-To-One Tutorials in Computing

    Give One-to-One Tutorials in Computing (in Person or over Skype). Tutorials - Operations Systems (Windows [XP, Vista and 7], Linux, Mac) Also .. Programming (Java and Python). Web Development (HTML, XHTML, CSS, PHP, MySQL) - WordPress and Joomla. Windows management and Simple Networking.
    £7.50 per-hour ... Contact on 

    e-mail: info@mydreamwave.com
    tchize@itechreload.co.uk
    Skype: Tchize_black1

    Sunday, 15 January 2012

    PHP and MySQL Basic & Ajax Basic Tutorial

    Basic tips for using phpMyAdmin and setting up databases in MySQL Adding, Creating, Editing, Deleting, Searching & Displaying Tables with HTML and PHP Programming a web form for interacting and graphing into the database.  Lots more PHP code that supplements, what you learned from the PHP course Tons and tons of unique tips that only a professional database programmer knows to...



    Installing the Web Developer plug-in for Firefox to help debug code Using the free Development IDE, Apanta Program web pages that done it ? 

    It need refreshing to load in new content HTML menus / buttons that trigger functions, Tabbed Menus for Opening CSS DIV, Windows Create Drag and Drop Taps for a Shopping Cart a Web Interface Lots of javascript, XML, CSS, DOM, HTML, PHP

    Download here:

    http://www.filesonic.com/file/AQIA7AJ/Php_and_Ajax.part1.rar
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    http://www.filesonic.com/file/ZNmSKO2/Php_and_Ajax.part4.rar
    or
    http://ul.to/ugshzjwd/Php_and_Ajax.part1.rar
    http://ul.to/gd2y5sj5/Php_and_Ajax.part2.rar
    http://ul.to/m777f413/Php_and_Ajax.part3.rar
    http://ul.to/96nfitc8/Php_and_Ajax.part4.rar

    How to check for open ports on Linux

    Checking for open ports is among the first steps to secure your device. Listening services may be the entrance for attackers who may exploit...