Resolving "Sorry, that domain is already setup (remove it from httpd.conf)" Error in cPanel/WHM

If you're a cPanel/WHM administrator, you might have encountered the frustrating error "Sorry, that domain is already set up (remove it from httpd.conf)" when trying to add a new domain. This error typically indicates that the domain name you're attempting to use is already associated with another account or configuration on your server.

In this guide, we'll break down the causes of this error and provide step-by-step instructions on how to resolve it.

Why Does This Error Occur?

There are two main reasons you might encounter this error:

Reason 1: The domain is already in use.

• The domain could be assigned as a primary, addon, or parked domain on another cPanel account.
• It might be lingering in the server's configuration even after being removed from an account.

Reason 2: Technical Glitches

• The removal process for the domain might not have been completed correctly, leaving remnants in the system.

Troubleshooting and Resolution

1. Check if the Domain is Actively Used

If the error is due to the domain already being associated with another account:

• Remove the domain: Log into the cPanel account that's using the domain and remove it as an addon, parked, or primary domain.

If you encounter the error "Error from park wrapper: Sorry, you do not control the domain" while trying to remove it, proceed to the next step.

2. Identify the Domain Owner and Remove Entries

1. Find the Owner: Use the following commands in the server's command line (SSH) to determine which account the domain is associated with:

   /scripts/whoowns example.com 

   If this doesn't yield results, try:

   grep example.com /var/cpanel/users/*

   (Replace "example.com" with the actual domain name.)

2. Remove Domain Entries: Once you know the owner account, remove any references to the domain from the following files:

   • /var/named/example.com.db
   • /etc/httpd/conf/httpd.conf (remove the virtual host entry)
   • /var/cpanel/users/username (remove entries related to the domain)
   • /etc/userdomains
   • /etc/localdomains
   • /etc/named.conf (remove entries related to the domain)
   • Remove DNS entry in WHM: Go to the DNS Zone Manager in WHM and remove the DNS zone for the domain.

3. Update User Domains: Finally, run the following command as root:

   /scripts/updateuserdomains

Important Considerations:

• Backups: Before making any changes to configuration files, it's crucial to have a backup of your server in case of unintended consequences.
• Technical Expertise: If you're not comfortable with editing configuration files, consider seeking help from your hosting provider or a qualified system administrator.

By following these steps, you should be able to resolve the "Sorry, that domain is already set up" error and successfully add the domain to the desired cPanel account.

Recovering Mistakenly Deleted LVM Partitions: A Lifesaver for Linux Admins

We've all been there – a moment of inattention or a typo, and suddenly a crucial LVM partition is gone. Thankfully, Linux offers a built-in safety net for these scenarios. The vgcfgrestore command can be your lifeline for recovering accidentally deleted LVM partitions, saving you from potential data loss and downtime.

Understanding the Safety Net: LVM Configuration Backups

Linux diligently maintains backup copies of your LVM configurations in the /etc/lvm/archive directory. This archive acts as a time machine, allowing you to rewind and restore your LVM setup to a previous state.

Recovering a Deleted LVM Partition: Step-by-Step

Let's walk through a real-world scenario. Suppose you've accidentally deleted a 10GB LVM partition belonging to a volume group named "my-vg." Here's how to recover it:

Step 1: Locate the Backup Configuration

First, you need to find the relevant backup file in the /etc/lvm/archive directory. The vgcfgrestore command makes this easy:

sudo vgcfgrestore --list my-vg

This will list all available backup configurations for your "my-vg" volume group. The output might look something like this:

my-vg_00001-123456789.vg
my-vg_00002-692643462.vg  
... 

Identify the backup file you want to use (e.g., my-vg_00002-692643462.vg).

Step 2: Restore the LVM Partition

Now, you can restore the LVM configuration using the backup file and the vgcfgrestore command:

sudo vgcfgrestore -f /etc/lvm/archive/my-vg_00002-692643462.vg my-vg

If successful, you'll see the message:

Restored volume group my-vg

Important Note: Before restoring, double-check that you've selected the correct backup file! Restoring the wrong configuration could lead to unintended consequences.

After the Restoration

Once the volume group is restored, you'll need to reactivate it:

sudo vgchange -ay my-vg

You should now be able to see and use your recovered LVM partition again.

Prevention is Key

While vgcfgrestore is a lifesaver, it's always better to prevent data loss in the first place. Consider these best practices:

• Regular Backups: Always maintain up-to-date backups of your entire system, including LVM metadata.
• Double-Check Commands: Be extremely careful when executing commands that modify LVM partitions.
• Use Snapshots: If you're unsure about a change, create an LVM snapshot first to have a rollback point.

Conclusion

The vgcfgrestore command is a powerful tool that can rescue you from the panic of accidentally deleting an LVM partition. By understanding how to use it and following preventive measures, you can confidently manage your LVM environment and ensure the safety of your data.

Using mdadm to Manage RAID and Multipath Storage on Linux: A Practical Guide with Examples

The mdadm command is a powerful tool for managing multiple device sets on Linux systems. It plays a crucial role in creating and maintaining RAID arrays, which provide redundancy and performance benefits, and multipath setups, which ensure data availability in case of hardware failure. Let's delve into how you can use mdadm to harness these powerful storage features, complete with practical examples.

Creating RAID Devices with mdadm

1. Define Your Configuration:

The /etc/mdadm.conf file is where you specify the devices and RAID level for your array.

Example: RAID 1 (Mirroring)

DEVICE /dev/sd[b,c]1  
ARRAY /dev/md0 level=raid1 raid-devices=2 /dev/sdb1 /dev/sdc1

This configuration creates a RAID 1 array (/dev/md0) that mirrors data across two devices (/dev/sdb1 and /dev/sdc1).

Example: RAID 5 (Striping with Parity)

DEVICE /dev/sd[b-d]1
ARRAY /dev/md0 level=raid5 raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1

This configuration creates a RAID 5 array (/dev/md0) that stripes data across three devices with parity information for fault tolerance.

2. Create the RAID Array:

Use mdadm with the -C (create) option and the details from your configuration:

# RAID 1 example
sudo mdadm -C /dev/md0 --level=raid1 --raid-devices=2 /dev/sdb1 /dev/sdc1

# RAID 5 example
sudo mdadm -C /dev/md0 --level=raid5 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1

3. Verify RAID Status:

Check the status of your newly created RAID array:

sudo mdadm --detail /dev/md0

You should see information about the RAID level, state (active, syncing, etc.), device status, and more.

Creating Multipath Devices with mdadm

Multipathing provides an additional layer of reliability by creating multiple paths to access a storage device.

sudo mdadm -C /dev/md1 --level=multipath --raid-devices=2 /dev/mapper/mpatha /dev/mapper/mpathb

This command creates a multipath device (/dev/md1) using two paths (/dev/mapper/mpatha and /dev/mapper/mpathb) that likely correspond to different physical disks.

Key Considerations

• Choose the Right RAID Level:
  • RAID 0: Best for performance but no redundancy.
  • RAID 1: Offers redundancy with mirroring.
  • RAID 5: Good balance of performance and redundancy.
  • RAID 6: More redundancy than RAID 5 but slightly slower.
  • RAID 10: Combines mirroring and striping for both performance and redundancy.
• Data Backup: RAID is not a backup solution; always maintain regular backups.
• Hardware Compatibility: Ensure your hardware (controllers, disks) supports your chosen RAID level.

Conclusion

mdadm empowers you to create robust and fault-tolerant storage solutions on Linux. By mastering its capabilities, you can optimize your server's performance and protect your valuable data.

Let me know if you'd like more in-depth examples or have any specific scenarios you'd like to explore!