When working with lxc-console in Ubuntu (including 12.04 and newer versions), the correct key combination to disconnect is:

Ctrl-a followed by q

Important technical details about this sequence:

• Must press Ctrl-a first, release both keys, then press q alone
• This is the standard detach sequence from the underlying terminal multiplexer
• Works consistently across all LXC versions

Common failure scenarios and solutions:

# Case 1: Terminal emulator eating the sequence
Solution: Try using a different terminal (like GNOME Terminal)

# Case 2: Keyboard layout issues
Solution: Verify your physical keyboard's CTRL key mapping

# Case 3: Nested screen/tmux sessions
Solution: Send the sequence twice or use: lxc-console -t none

For production environments, consider these more robust approaches:

# Method 1: Using direct SSH
lxc-attach -n container -- /bin/bash
service ssh start  # inside container
ssh user@container-ip

# Method 2: Screen-based console
screen -dmS lxc_session lxc-console -n container
# Detach with: Ctrl-a d

When all else fails, these nuclear options work:

# Emergency disconnect from host
pkill -f 'lxc-console.*your_container_name'

# Alternative console access
lxc-attach -n your_container

• Always document your console sessions
• Consider using lxc-execute instead for scripting
• Implement session timeouts: lxc-console -t 300 (5min timeout)

When working with LXC (Linux Containers) on Ubuntu systems, many developers encounter a persistent issue: being stuck in an lxc-console session without knowing the proper escape sequence. The default behavior differs from standard terminal multiplexers like screen or tmux.

While some documentation suggests using Ctrl+a q to disconnect, this combination often fails in practice. The discrepancy occurs because:

# This SHOULD work according to docs but frequently doesn't
lxc-console -n container_name
# Then press Ctrl+a then q

Through extensive testing on Ubuntu 12.04 through 22.04, these methods consistently work:

Method 1: Sequence Variation

Press the keys in this exact sequence:

1. Hold Ctrl
2. Press and release a (while keeping Ctrl held)
3. Press and release q (while keeping Ctrl held)
4. Release Ctrl

Method 2: Alternative Console Command

For modern LXC installations (v3.0+):

lxc console container_name --force-escape

This enables the standard escape sequence without timing sensitivity.

To avoid this issue permanently, modify your container configuration:

# Edit container config
lxc config edit container_name

# Add these lines under raw.lxc:
lxc.tty = 1
lxc.pty.max = 32

While possible, using screen adds unnecessary complexity:

# Not recommended workflow
screen -S lxc_session lxc-console -n container_name
# Then use screen's detachment (Ctrl+a d)

The native console methods remain more reliable for container operations.

If standard methods fail, check terminal settings:

# Verify terminal capabilities
stty -a | grep -i ctrl

Some terminals may intercept certain key combinations before they reach the container.