Task 4.2 — Configuration Management "for the Poor"

Overview

Bash scripts to deploy and verify an NTP server configuration on Ubuntu.

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Scripts

ntp_deploy.sh

• Installs the NTP server package
• Removes default NTP server entries from ntp.conf (e.g. 0.ubuntu.pool.ntp.org)
• Configures ua.pool.ntp.org as the sole NTP server
• Restarts the NTP service
• Registers ntp_verify.sh to run once per minute via cron

ntp_verify.sh

• Checks whether the NTP process is running; starts it if not
• Checks ntp.conf for unauthorized changes:
  • Outputs the diff to stdout if changes are detected
  • Restores ntp.conf to its deployed state (ua.pool.ntp.org only)
  • Restarts the NTP service

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Additional Requirements

1. Both scripts must be uploaded to a GitHub repository named task4_2.
2. The repository must contain exactly two files: ntp_deploy.sh and ntp_verify.sh.
3. ntp_verify.sh may be run multiple times during task verification.

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Environment Setup Guide

This section describes how to spin up a local Ubuntu 16.04 environment that matches the grader's setup so you can verify the solution before submission.

Option A — Docker (recommended, works on Windows / macOS / Linux)

Prerequisites: Docker Desktop installed and running.

# 1. Pull the Ubuntu 16.04 image
docker pull ubuntu:16.04

# 2. Start a privileged container (required for the 'service' command)
docker run -it --privileged --name ntp-test ubuntu:16.04 /bin/bash

Inside the container:

# 3. Install prerequisites
apt-get update && apt-get install -y git cron

# 4. Clone the repository (replace with your actual URL)
git clone https://github.com/<your-username>/task4_2 /root/task4_2
cd /root/task4_2

# 5. Run the deploy script
bash ntp_deploy.sh

# 6. Verify NTP config — should produce no output (no changes)
bash ntp_verify.sh

# 7. Simulate a config change, then verify again
sed -i 's/ua.pool.ntp.org/us.pool.ntp.org/' /etc/ntp.conf
bash ntp_verify.sh
# Expected: prints NOTICE header + unified diff, then restores the file

# 8. Simulate a stopped daemon, then verify
service ntp stop
bash ntp_verify.sh
# Expected: prints "NOTICE: ntp is not running" and starts the service

# 9. Confirm cron mail delivery (wait ~1 min after a config change)
cat /var/mail/root

To re-use the container later:

docker start -ai ntp-test

To start fresh:

docker rm ntp-test

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Option B — Vagrant (closer to bare-metal, good for cron testing)

Prerequisites: VirtualBox and Vagrant installed.

Create a Vagrantfile in any working directory:

Vagrant.configure("2") do |config|
  config.vm.box = "ubuntu/xenial64"
  config.vm.provision "shell", inline: <<-SHELL
    apt-get update
    apt-get install -y git
  SHELL
end

# Start and SSH into the VM
vagrant up
vagrant ssh

# Then follow steps 4–9 from Option A above (inside the VM)
sudo -i
git clone https://github.com/<your-username>/task4_2 /root/task4_2
cd /root/task4_2
bash ntp_deploy.sh

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Verification Checklist

Check	Command	Expected result
NTP installed	dpkg -l ntp	Package listed
Only ua.pool.ntp.org in conf	grep '^pool' /etc/ntp.conf	Single line: pool ua.pool.ntp.org iburst
NTP running	service ntp status	active (running)
Backup exists	ls /etc/ntp.conf.bak	File present
Cron entry registered	grep ntp_verify /etc/crontab	Entry with * * * * *
Verify script — no diff	bash ntp_verify.sh	No output
Verify script — diff	Corrupt conf, then run script	NOTICE header + diff printed, conf restored
Verify script — daemon down	service ntp stop && bash ntp_verify.sh	NOTICE printed, daemon restarted

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Verification Procedure

Environment

• OS: Ubuntu Xenial 16.04 Server
• User: root
• Pre-installed packages: sendmail
• Network: internet access available

Execution Rules

• The repository is cloned by URL (e.g. https://github.com/user/task4_2); a different repository name results in automatic failure.
• ntp_deploy.sh is launched automatically from the repository root; a different script name or subdirectory location results in automatic failure.
• ntp_verify.sh may also be run manually from the console without waiting for cron.

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Expected Behavior

After ntp_deploy.sh

• ntp.conf must differ from the default only in the NTP server section, with ua.pool.ntp.org as the sole configured server.

ntp_verify.sh — no changes detected

• Produces no output and does not restart the NTP service.

ntp_verify.sh — changes detected in ntp.conf

• Prints the following header line to stdout:

  NOTICE: /etc/ntp.conf was changed. Calculated diff:
  

• Outputs the diff in unified format immediately after the header.
• Restores ntp.conf to the correct state (default settings + ua.pool.ntp.org only).
• Restarts the NTP daemon.

Sample output:

NOTICE: /etc/ntp.conf was changed. Calculated diff:
--- /etc/ntp.conf.bak   2018-03-27 16:45:40.693954805 +0000
+++ /etc/ntp.conf       2018-03-27 16:56:55.723992297 +0000
@@ -20 +20 @@
-pool ua.pool.ntp.org
+pool us.pool.ntp.org

ntp_verify.sh — NTP daemon is stopped

• Outputs NOTICE: ntp is not running to stdout.
• Starts the NTP service.

Note: When triggered via cron, stdout output is delivered to /var/mail/root and will be verified there.