Defining a simple module to configure time
by Uday R. Sawant, William Leemans, Jonathan Hobson, Oliver Pelz
Linux: Powerful Server Administration
- Linux: Powerful Server Administration
- Table of Contents
- Linux: Powerful Server Administration
- Linux: Powerful Server Administration
- Credits
- Preface
- 1. Module 1
- 1. Managing Users and Groups
- 2. Networking
- Introduction
- Connecting to a network with a static IP
- Installing the DHCP server
- Installing the DNS server
- Hiding behind the proxy with squid
- Being on time with NTP
- Discussing load balancing with HAProxy
- Tuning the TCP stack
- Troubleshooting network connectivity
- Securing remote access with OpenVPN
- Securing a network with uncomplicated firewall
- Securing against brute force attacks
- Discussing Ubuntu security best practices
- 3. Working with Web Servers
- Introduction
- Installing and configuring the Apache web server
- Serving dynamic contents with PHP
- Hosting multiple websites with a virtual domain
- Securing web traffic with HTTPS
- Installing Nginx with PHP_FPM
- Setting Nginx as a reverse proxy
- Load balancing with Nginx
- Setting HTTPs on Nginx
- Benchmarking and performance tuning of Apache
- Securing the web server
- Troubleshooting the web server
- 4. Working with Mail Servers
- 5. Handling Databases
- Introduction
- Installing relational databases with MySQL
- Storing and retrieving data with MySQL
- Importing and exporting bulk data
- Adding users and assigning access rights
- Installing web access for MySQL
- Setting backups
- Optimizing MySQL performance – queries
- Optimizing MySQL performance – configuration
- Creating MySQL replicas for scaling and high availability
- Troubleshooting MySQL
- Installing MongoDB
- Storing and retrieving data with MongoDB
- 6. Network Storage
- 7. Cloud Computing
- 8. Working with Containers
- Introduction
- Installing LXD, the Linux container daemon
- Deploying your first container with LXD
- Managing LXD containers
- Managing LXD containers – advanced options
- Setting resource limits on LXD containers
- Networking with LXD
- Installing Docker
- Starting and managing Docker containers
- Creating images with a Dockerfile
- Understanding Docker volumes
- Deploying WordPress using a Docker network
- Monitoring Docker containers
- Securing Docker containers
- 9. Streaming with Ampache
- 10. Communication Server with XMPP
- 11. Git Hosting
- Introduction
- Installing Git
- Creating a local repository with Git CLI
- Storing file revisions with Git commit
- Synchronizing the repository with a remote server
- Receiving updates with Git pull
- Creating repository clones
- Installing GitLab, your own Git hosting
- Adding users to the GitLab server
- Creating a repository with GitLab
- Automating common tasks with Git hooks
- 12. Collaboration Tools
- 13. Performance Monitoring
- 14. Centralized Authentication Service
- 2. Module 2
- 1. Installing CentOS
- Introduction
- Downloading CentOS and confirming the checksum on Windows or OS X
- Creating USB installation media on Windows or OS X
- Performing an installation of CentOS using the graphical installer
- Running a netinstall over HTTP
- Installing CentOS 7 using a kickstart file
- Getting started and customising the boot loader
- Troubleshooting the system in rescue mode
- Updating the installation and enhancing the minimal install with additional administration and development tools
- 2. Configuring the System
- Introduction
- Navigating text files with less
- Introduction to Vim
- Speaking the right language
- Synchronizing the system clock with NTP and the chrony suite
- Setting your hostname and resolving the network
- Building a static network connection
- Becoming a superuser
- Customizing your system banners and messages
- Priming the kernel
- 3. Managing the System
- Introduction
- Knowing and managing your background services
- Troubleshooting background services
- Tracking system resources with journald
- Configuring journald to make it persistent
- Managing users and their groups
- Scheduling tasks with cron
- Synchronizing files and doing more with rsync
- Maintaining backups and taking snapshots
- Monitoring important server infrastructure
- Taking control with GIT and Subversion
- 4. Managing Packages with YUM
- 5. Administering the Filesystem
- 6. Providing Security
- 7. Building a Network
- 8. Working with FTP
- 9. Working with Domains
- 10. Working with Databases
- 11. Providing Mail Services
- 12. Providing Web Services
- 13. Operating System-Level Virtualization
- 14. Working with SELinux
- 15. Monitoring IT Infrastructure
- 1. Installing CentOS
- 3. Module 3
- 1. Working with KVM Guests
- 2. Deploying RHEL "En Masse"
- 3. Configuring Your Network
- 4. Configuring Your New System
- 5. Using SELinux
- 6. Orchestrating with Ansible
- 7. Puppet Configuration Management
- 8. Yum and Repositories
- 9. Securing RHEL 7
- 10. Monitoring and Performance Tuning
- Bibliography
- Index
Modules are collections of manifests and files that define how to install and configure various components. Manifests contain the instructions to apply to a system's configuration. In this recipe, we'll create a simple module to install and configure the NTP daemon.
Puppet has a strict way of organizing modules. Your modules should always be stored in /etc/puppet/modules. Every module is a directory within this directory, containing the necessary directories that in turn contain manifests, files, templates, and so on.
In this recipe, we'll create the necessary directory structure, manifests, and files to configure your system's time. Perform the following steps:
- Create
ntp/manifestsin/etc/puppet/modulesvia the following command:~]# mkdir -p /etc/puppet/modules/ntp/manifests - Create
ntp/templatesto house all the templates used by the puppet module through the following:~]# mkdir -p /etc/puppet/modules/ntp/templates - Now, create the
install.ppfile in/etc/puppet/modules/ntp/manifestswith the following contents:class ntp::install inherits ntp { package { 'ntp': ensure => installed, } } - Create the
config.ppfile in/etc/puppet/modules/ntp/manifestswith the following contents:class ntp::config inherits ntp { file { '/etc/ntp.conf': ensure => file, owner => 'root', group => 'root', mode => 0644, content => template("ntp/ntp.conf.erb"), } } - Next, create the
ntp.conf.erbtemplate file in/etc/puppet/modules/ntp/templateswith the following contents:driftfile /var/lib/ntp/drift restrict default nomodify notrap nopeer noquery restrict 127.0.0.1 restrict ::1 server 0.be.pool.ntp.org iburst server 1.be.pool.ntp.org iburst server 2.be.pool.ntp.org iburst server 3.be.pool.ntp.org iburst includefile /etc/ntp/crypto/pw keys /etc/ntp/keys disable monitor
- Create the
service.ppfile in/etc/puppet/modules/ntp/manifestswith the following contents:class ntp::service inherits ntp { service { 'ntp': ensure => running, enable => true, hasstatus => true, hasrestart => true, require => Package['ntp'], } } - Finally, create the
init.ppfile that binds them all together in/etc/puppet/modules/ntp/manifestswith the following contents:class ntp { include ntp::install include ntp::config include ntp::service }
When applying a module to a system, it applies the directives found in the module's init.pp manifest.
As you can see, we created a template file that is "automagically" distributed to the clients. Puppet automatically creates a file share for the templates and files directories.
As you can see in the config.pp file, the template references ntp/ntp.conf.erb. Puppet will automatically resolve this to the correct location (ntp/templates/ntp.conf.erb).
I created four manifests to install and configure Puppet. This could be easily achieved by just creating one monolithic init.pp manifest with the contents of the other three files. When you start creating complex manifests, you'll be happy to have split them up.
If you want to have a single location for all the assets (templates and files) you use in your modules, you will have to define a separate file share for this location in the /etc/puppet/fileserver.conf file, as follows:
[mount_point]
path /path/to/files
allow *Read up on Puppet Modules through the link https://docs.puppetlabs.com/puppet/3.8/reference/modules_fundamentals.html.
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