CS Servers Quick Reference Guide

1 Managing Email Aliases

SSH into 'Ark':
```
ssh ndodds@ark
```
Navigate to the configuration directory:
```
cd /etc/postfix/
```
Check out the file for editing:
```
co -l aliases_clinic
```
Open the file in the vim editor:
```
vim aliases_clinic
```
Check in the file after editing:
```
ci -u aliases_clinic
```
Process changes and update alias database:
```
newaliases
```

2 User Password Management

SSH into Cortana:
```
ssh cortana
```
Change a user's password (replace USERNAME with the actual username):
```
passwd -i opendirectory -u ndodds USERNAME
```

3 Service Management

SSH into Hopper:
```
ssh root@hopper
```
Restart the sssd service (OpenRC):
```
/etc/init.d/sssd restart
```
Restart the sssd service (systemd - for Lovelace or Granville):
```
systemctl restart sssd
```

4 Account Lookup Tools

Display user ID and group information:
```
id ndodds
```
Fetch the password entry for the user:
```
getent passwd ndodds
```
Display detailed user information with finger:
```
finger dodds
```

5 LDAP Account Management

Fetch basic LDAP entries for a user:
```
ldapsearch -LLLx uid=ndodds
```
Fetch specific LDAP fields (common name and email):
```
ldapsearch -LLLx uid=ndodds cn mail
```

6 Network and DNS Configuration

Find the current IP address on the local client:
```
ip addr
```
SSH into the network server:
```
ssh mudd@neutron.cs.hmc.edu
```
Locate the DHCP binding for the IP (replace xxx with your IP suffix):
```
show ip dhcp bind | incl 134.173.43.xxx
```
Clear existing DHCP binding if necessary:
```
clear ip dhcp bind 134.173.43.xxx
```
Note: This removes the binding from the active table, but the client may still attempt to renew with the old IP. The following method ensures a complete removal.

Alternative: Clear binding from configuration (more thorough):
```
conf term
ip dhcp pool guest43
no addr 134.173.43.xxx
```
This removes the static binding from the DHCP pool configuration itself, preventing the server from reassigning this binding.

Enter configuration mode:
```
conf term
```
Define a DHCP pool:
```
ip dhcp pool guest43
```
Set static IP with client ID (replace with your specific values):
```
addr 134.173.43.xxx client-id 01xx:xx:xx:xx:xx:xx
```
Important: The client-id must begin with 01 followed by the MAC address. The 01 prefix indicates the hardware type (Ethernet). DHCP uses this format to distinguish between different types of network interfaces. Without the correct prefix, the binding won't match the client's DHCP request.

Save the configuration to disk:
```
write mem
```

7 Editing DNS Zone Files

SSH into Ark:
```
ssh ndodds@ark.cs.hmc.edu
```
Navigate to the DNS directory:
```
cd /mnt/dns
```
Freeze the zone for editing:
```
sudo rndc freeze cs.hmc.edu
```
Check out the zone file:
```
sudo co -l cs.hmc.edu
```
Edit the zone file (remember to increment the serial number):
```
sudo vim cs.hmc.edu
```
Important: Don't forget to increment the serial number at the top of the file.

Check in the changes:
```
sudo ci -u cs.hmc.edu
```
Thaw the zone:
```
sudo rndc thaw cs.hmc.edu
```

8 Disk Quota Management

Edit quota for a specific user:
```
sudo edquota username
```
View the quota for a specific user:
```
sudo checkquota -v username
```
Reset user quota to default:
```
sudo edquota -p quotatemplate username
```

9 APT History Log Processing

Process both compressed and uncompressed APT history logs:

for log in /var/log/apt/history.log /var/log/apt/history.log.*; do
  if [[ "$log" == *.gz ]]; then
    zcat "$log" | perl -00 -lne 'next unless m/\nRequested-By: (\w+) \(\d+\) /; 
      my $user = $1; 
      printf "%s: %s\n", $user, $1 if m/Commandline:\s+(.*)/' | grep install
  else
    cat "$log" | perl -00 -lne 'next unless m/\nRequested-By: (\w+) \(\d+\) /; 
      my $user = $1; 
      printf "%s: %s\n", $user, $1 if m/Commandline:\s+(.*)/' | grep install
  fi
done

10 NVIDIA Management

Unload the NVIDIA kernel module:
```
modprobe -r nvidia
```
Removes the NVIDIA driver module from the kernel. Useful when troubleshooting driver issues or before updating drivers. All programs using the GPU must be stopped first.

Load NVIDIA device files:
```
nvidia-modprobe
```
Creates the NVIDIA device files in /dev if they don't exist. Required for GPU access after driver installation or system boot. Typically runs automatically but can be invoked manually.

Check which processes are using NVIDIA devices:
```
sudo lsof /dev/nvidia*
```
Lists all processes with open file handles to NVIDIA devices. Essential for diagnosing "device busy" errors or identifying which programs need to be closed before unloading the driver.

11 NVMe Drive Cloning & Upgrade (Ubuntu Method)

1. Prepare Hardware

Shut down the system. Move the original NVMe drive to an external USB adapter, then install the new (larger) NVMe drive into the motherboard's M.2 slot.

2. Boot into Live Environment

Insert your Ubuntu USB Installer. Boot the machine and select "Try Ubuntu without installing". Once the desktop loads, open a Terminal (Ctrl+Alt+T).

3. Identify Your Drives

Run the following to list all connected storage devices:
```
lsblk -o NAME,MODEL,SIZE,TYPE,FSTYPE
```
Identify your two drives based on size:
- Source (Old Drive): Usually /dev/sda or /dev/sdb (connected via USB).
- Destination (New Drive): Usually /dev/nvme0n1 (internal M.2 slot).
4. Clone the Drive

Critical Warning: Double-check your if (Input File) and of (Output File). Writing to the wrong drive is irreversible.
```
sudo dd if=/dev/sdX of=/dev/nvme0n1 bs=64K conv=noerror,sync status=progress
```
Replace /dev/sdX with your USB adapter identifier (e.g., /dev/sda). The bs=64K flag speeds up the copy significantly.

5. Fix GPT Table & Resize Partition

After cloning, the backup partition table is now "stuck" in the middle of the drive (where the old disk ended). We must move it to the end of the new disk.

Launch the partition editor:
```
sudo parted /dev/nvme0n1
```
You will immediately see a warning about the GPT table. Type Fix when prompted:
```
Warning: Not all of the space available to /dev/nvme0n1 appears to be used...
Fix/Ignore? Fix
```
Now, find the partition number you want to expand (usually partition 2 or the largest one):
```
(parted) print
```
Resize the partition to fill the disk:
```
(parted) resizepart 2 100%
(parted) quit
```
6. Check & Resize Filesystem

Now that the partition is larger, we must expand the filesystem inside it to match.

First, run a safety check on the filesystem:
```
sudo e2fsck -f /dev/nvme0n1p2
```
Then, resize it (defaults to max available size):
```
sudo resize2fs /dev/nvme0n1p2
```
7. Finalize

Shut down the computer, remove the USB boot drive and the external USB adapter. Boot normally from the new internal NVMe.

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