How to fix E: Could not get lock /var/lib/dpkg/lock (unattended-upgrades running) in APT

First, verify that unattended-upgrades is the actual process holding the lock:

sudo ps aux | grep unattended-upgrades

If you see a process with 'unattended-upgrades' in the command line, it's running. If it's not there, the lock may be stale.

The safest solution is to simply wait. Unattended-upgrades typically takes 1-10 minutes depending on system resources and network speed. Monitor its progress:

sudo tail -f /var/log/unattended-upgrades/unattended-upgrades.log

Once the process completes, the lock will be released automatically and you can run apt commands normally.

Use lsof to see exactly which process has the lock:

sudo lsof /var/lib/dpkg/lock
sudo lsof /var/lib/dpkg/lock-frontend
sudo lsof /var/lib/apt/lists/lock

The output shows the process ID (PID) and command that holds the lock. This helps confirm it's safe to proceed with other steps.

If you need to run apt immediately, you can stop the service:

sudo systemctl stop unattended-upgrades

Run your apt commands, then restart it:

sudo systemctl start unattended-upgrades

This is safe because unattended-upgrades will resume checking for updates on the next scheduled time.

For automated deployments or Ansible/Packer provisioning, use a wait loop to avoid lock conflicts:

#!/bin/bash
echo 'Waiting for unattended-upgrades to finish...'
while sudo lsof /var/lib/dpkg/lock-frontend 2>/dev/null | grep -q unattended; do
  sleep 5
done
echo 'Lock released. Proceeding with apt commands...'

Add this before your apt commands in provisioning scripts. Use a timeout to prevent infinite waiting:

for i in {1..120}; do
  if ! sudo lsof /var/lib/dpkg/lock-frontend 2>/dev/null | grep -q unattended; then
    break
  fi
  sleep 5
done

Only do this if:
1. You confirmed unattended-upgrades is NOT running (ps aux shows nothing)
2. You confirmed other apt processes are NOT running
3. You cannot wait

Removing locks while apt is running can corrupt the package database.

sudo rm /var/lib/dpkg/lock
sudo rm /var/lib/dpkg/lock-frontend
sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock
sudo dpkg --configure -a

Then attempt your apt command again.

If unattended-upgrades continues to interfere, you can disable automatic updates (not recommended for security):

sudo systemctl disable apt-daily.timer
sudo systemctl disable apt-daily-upgrade.timer
sudo systemctl stop apt-daily.service
sudo systemctl stop apt-daily-upgrade.service

Or edit the configuration:

sudo nano /etc/apt/apt.conf.d/20auto-upgrades

Change these lines:

APT::Periodic::Update-Package-Lists "0";
APT::Periodic::Download-Upgradeable-Packages "0";
APT::Periodic::AutocleanInterval "0";
APT::Periodic::Unattended-Upgrade "0";

Note: This disables security updates. Only do this in development or test environments.