recodex-wiki/Installation.md

Installation

Installation of whole ReCodEx solution is a very complex process. It is recommended to have good unix skills with basic knowledge of project architecture.

There are a lot of different GNU/Linux distributions with different package management, naming convention and version release policies. So it is impossible to cover all of the possible variants. We picked one distribution, which is fully supported by automatic installation script, for others there are brief information about installation in every project component's own chapter.

Distribution of our choice is CentOS, currently in version 7. It is a well known server distribution, derived from enterprise distrubution from Red Hat, so it is very stable and widely used system with long term support. There are EPEL additional repositories from Fedora project, which adds newer versions of some packages into CentOS, which allows us to use current environment. Also, rpm packages are much easier to build (for example from Python sources) and maintain.

The big rival of CentOS in server distributions field is Debian. We are running one instance of ReCodEx on Debian too. You need to use testing repositories to use some decent package versions. It is easy to mess your system easily, so create file /etc/apt/apt.conf with content of APT::Default-Release "stable";. After you add testing repos to /etc/apt/sources.list, you can install packages from there like $ sudo apt-get -t testing install gcc.

Some components are also capable of running in Windows environment. However setting up Windows OS is a little bit of pain and it is not supposed to run ReCodEx in this way. Only worker component may be needed to run on Windows, so we are providing clickable installer including dependencies. Just for info, all components should be able to run on Windows, only broker was not tested and may require small tweaks to properly work.

Ansible installer

For automatic installation is used set of Ansible scripts. Ansible is one of the best known and used tools for automatic server management. It is required only to have SSH access to the server and ansible installed on the client machine. For further reading is supposed basic Ansible knowledge. For more info check their documentation.

All Ansible scripts are located in utils repository, installation directory. Ansible files are pretty self-describing, they can be also use as template for installation to different systems. Before installation itself it is required to edit two files -- set addresses of hosts and values of some variables.

Hosts configuration

First, it is needed to set IP addresses of your computers. Common practise is to have multiple files with definitions, one for development, another for production for example. Example configuration is in development file. Each component of ReCodEx project can be installed on different server. Hosts can be specified as hostnames or IP addresses, optionally with port of SSH after colon.

Shorten example of hosts config:

[workers]
127.0.0.1:22

[broker]
127.0.0.1:22

[all:children]
workers
broker

Variables

Configurable variables are saved in group_vars/all.yml file. Syntax is basic key-value pair per line, separated by colon. Values with brief description:

• source_dir -- Directory, where to store all sources from GitHub. Defaults /opt/recodex.
• mysql_root_password -- Password of root user of MySQL database. Will be set after installation and saved to /root/.my.cnf file.
• mysql_recodex_username -- MySQL username for ReCodEx API access.
• mysql_recodex_password -- Password for the user above.
• admin_email -- Email of administrator. Used when configuring Apache webserver.
• recodex_hostname -- Hostname where the API and web app will be accessible. For example "recodex.projekty.ms.mff.cuni.cz".
• webapp_node_addr -- IP address of NodeJS server running web app. Defaults to "127.0.0.1" and should not be changed.
• webapp_node_port -- Port to above.
• webapp_public_addr -- Public address, where web server for web app will listen. Defaults to "*".
• webapp_public_port -- Port to above.
• webapp_firewall -- Open port for web app in firewall, values "yes" or "no".
• webapi_public_endpoint -- Public URL when the API will be running, for example "https://recodex.projekty.ms.mff.cuni.cz:4000/v1".
• webapi_public_addr -- Public address, where web server for API will listen. Defaults to "*".
• webapi_public_port -- Port to above.
• webapi_firewall -- Open port for API in firewall, values "yes" or "no".
• database_firewall -- Open port for database in firewall, values "yes" or "no".
• broker_to_webapi_addr -- Address, where API can reach broker. Private one is recommended.
• broker_to_webapi_port -- Port to above.
• broker_firewall_api -- Open above port in firewall, "yes" or "no".
• broker_to_workers_addr -- Address, where workers can reach broker. Private one is recommended.
• broker_to_workers_port -- Port to above.
• broker_firewall_workers -- Open above port in firewall, "yes" or "no".
• broker_notifier_address -- URL (on API), where broker will send notifications, for example "https://recodex.projekty.ms.mff.cuni.cz/v1/broker-reports".
• broker_notifier_port -- Port to above, should be the same as for API itself (webapi_public_port)
• broker_notifier_username -- Username for HTTP Authentication for reports
• broker_notifier_password -- Password for HTTP Authentication for reporst
• monitor_websocket_addr -- Address, where websocket connection from monitor will be available
• monitor_websocket_port -- Port to above.
• monitor_firewall_websocket -- Open above port in firewall, "yes" or "no".
• monitor_zeromq_addr -- Address, where monitor will be available on ZeroMQ socket for broker to receive reports.
• monitor_zeromq_port -- Port to above.
• monitor_firewall_zeromq -- Open above port in firewall, "yes" or "no".
• fileserver_addr -- Address, where fileserver will serve files.
• fileserver_port -- Port to above.
• fileserver_firewall -- Open above port in firewall, "yes" or "no".
• fileserver_username -- Username for HTTP Authentication for access the fileserver.
• fileserver_password -- Password for HTTP Authentication for access the fileserver.
• worker_cache_dir -- File cache storage for workers. Defaults to "/tmp/recodex/cache".
• worker_cache_age -- How long hold fetched files in worker cache, in seconds.
• isolate_version -- Git tag of Isolate version worker depends on.

Installation itself

With your computers installed with CentOS and configuration modified it is time to run the installation.

$ ansible-playbook -i development recodex.yml

This command installs all components of ReCodEx onto machines listed in development file. It is possible to install only specified parts of project, just use component's YAML file instead of recodex.yml.

Ansible expects to have password-less access to the remote machines. If you have not such setup, use options --ask-pass and --ask-become-pass.

Manual installation

Worker

Dependencies

Worker specific requirements are written in this section. It covers only basic requirements, additional runtimes or tools may be needed depending on type of use. The package names are for CentOS if not specified otherwise.

• ZeroMQ in version at least 4.0, packages zeromq and zeromq-devel (libzmq3-dev on Debian)
• YAML-CPP library, yaml-cpp and yaml-cpp-devel (libyaml-cpp0.5v5 and libyaml-cpp-dev on Debian)
• libcurl library libcurl-devel (libcurl4-gnutls-dev on Debian)
• libarchive library as optional dependency. Installing will speed up build process, otherwise libarchive is built from source during installation. Package name is libarchive and libarchive-devel (libarchive-dev on Debian)

Install Isolate from source (only for Linux installations)

First, we need to compile sandbox Isolate from source and install it. Current worker is tested against version 1.3, so this version needs to be checked out. Assume that we keep source code in /opt/src dir. For building man page you need to have package asciidoc installed.

$ cd /opt/src
$ git clone https://github.com/ioi/isolate.git
$ cd isolate
$ git checkout v1.3
$ make
# make install && make install-doc

For proper work Isolate depends on several advanced features of the Linux kernel. Make sure that your kernel is compiled with CONFIG_PID_NS, CONFIG_IPC_NS, CONFIG_NET_NS, CONFIG_CPUSETS, CONFIG_CGROUP_CPUACCT, CONFIG_MEMCG. If your machine has swap enabled, also check CONFIG_MEMCG_SWAP. With which flags was your kernel compiled with can be found in /boot directory, file config- and version of your kernel. Red Hat based distributions should have these enabled by default, for Debian you you may want to add the parameters cgroup_enable=memory swapaccount=1 to the kernel command-line, which can be set by adding value GRUB_CMDLINE_LINUX_DEFAULT to /etc/default/grub file.

For better reproducibility of results, some kernel parameters can be tweaked:

• Disable address space randomization. Create file /etc/sysctl.d/10-recodex.conf with content kernel.randomize_va_space=0. Changes will take effect after restart or run sysctl kernel.randomize_va_space=0 command.
• Disable dynamic CPU frequency scaling. This requires setting the cpufreq scaling governor to performance.

Clone worker source code repository

$ git clone https://github.com/ReCodEx/worker.git
$ git submodule update --init

Install worker on Linux

It is supposed that your current working directory is that one with clonned worker source codes.

• Prepare environment running mkdir build && cd build
• Build sources by cmake .. following by make
• Build binary package by make package (may require root permissions). Note that rpm and deb packages are build in the same time. You may need to have rpmbuild command (usually as rpmbuild or rpm package) or edit CPACK_GENERATOR variable in CMakeLists.txt file in root of source code tree.
• Install generated package through your package manager (yum, dnf, dpkg).

The worker installation process is composed of following steps:

• create config file /etc/recodex/worker/config-1.yml
• create systemd unit file /etc/systemd/system/recodex-worker@.service
• put main binary to /usr/bin/recodex-worker
• put judges binaries to /usr/bin/ directory
• create system user and group recodex with /sbin/nologin shell (if not already existing)
• create log directory /var/log/recodex
• set ownership of config (/etc/recodex) and log (/var/log/recodex) directories to recodex user and group

Note: If you do not want to generate binary packages, you can just install the project with make install (as root). But installation through your distribution's package manager is preferred way to keep your system clean and manageable in long term horizon.

Install worker on Windows

From beginning we are determined to support Windows operating system on which some of the workers may run (especially for projects in C# programming language). Support for Windows is quite hard and time consuming and there were several problems during the development. To ensure capability of compilation on Windows we set up CI for Windows named Appveyor. However installation should be easy due to provided installation script.

There are only two additional dependencies needed, Windows 7 and higher and Visual Studio 2015+. Provided simple installation batch script should do all the work on Windows machine. Officially only VS2015 and 32-bit compilation is supported, because of hardcoded compile options in installation script. If different VS or different platform is needed, the script should be changed to appropriate values, which is simple and straightforward.

Mentioned script is placed in install directory alongside supportive scripts for UNIX systems and is named win-build.cmd. Provided script will do almost all the work connected with building and dependency resolving (using NuGet package manager and msbuild building system). Script should be run under 32-bit version of Developer Command Prompt for VS2015 and from install directory.

Building and installing of worker is then quite simple, script has command line parameters which can be used to specify what will be done:

• -build -- It is the default options if none specified. Builds worker and its tests, all is saved in build folder and subfolders.
• -clean -- Cleanup of downloaded NuGet packages and built application/libraries.
• -test -- Build worker and run tests on compiled test cases.
• -package -- Generation of clickable installation using cpack and NSIS (has to be installed on machine to get this to work).

install> win-build.cmd  # same as: win-build.cmd -build
install> win-build.cmd -clean
install> win-build.cmd -test
install> win-build.cmd -package

All build binaries and cmake temporary files can be found in build folder, classically there will be subfolder Release which will contain compiled application with all needed dlls. Once if clickable installation binary is created, it can be found in build folder under name recodex-worker-VERSION-win32.exe. Sample screenshot can be found on following picture.

Usage

A systemd unit file is distributed with the worker to simplify its launch. It integrates worker nicely into your Linux system and allows you to run it automatically on system startup. It is possible to have more than one worker on every server, so the provided unit file is templated. Each instance of the worker unit has a unique string identifier, which is used for managing that instance through systemd. By default, only one worker instance is ready to use after installation and its ID is "1".

• Starting worker with id "1" can be done this way:

# systemctl start recodex-worker@1.service

Check with

# systemctl status recodex-worker@1.service

if the worker is running. You should see "active (running)" message.

• Worker can be stopped or restarted accordigly using systemctl stop and systemctl restart commands.
• If you want to run worker after system startup, run:

# systemctl enable recodex-worker@1.service

For further information about using systemd please refer to systemd documentation.

Adding new worker

To add a new worker you need to do a few steps:

• Make up an unique string ID.
• Copy default configuration file /etc/recodex/worker/config-1.yml to the same directory and name it config-<your_unique_ID>.yml
• Edit that config file to fit your needs. Note that you must at least change worker-id and logger file values to be unique.
• Run new instance using

# systemctl start recodex-worker@<your_unique_ID>.service

Broker

Dependencies

Broker has similar basic dependencies as worker, for recapitulation:

• ZeroMQ in version at least 4.0, packages zeromq and zeromq-devel (libzmq3-dev on Debian)
• YAML-CPP library, yaml-cpp and yaml-cpp-devel (libyaml-cpp0.5v5 and libyaml-cpp-dev on Debian)
• libcurl library libcurl-devel (libcurl4-gnutls-dev on Debian)

Clone broker source code repository

$ git clone https://github.com/ReCodEx/broker.git
$ git submodule update --init

Install broker

Installation of broker program does following step to your computer:

• create config file /etc/recodex/broker/config.yml
• create systemd unit file /etc/systemd/system/recodex-broker.service
• put main binary to /usr/bin/recodex-broker
• create system user and group recodex with nologin shell (if not existing)
• create log directory /var/log/recodex
• set ownership of config (/etc/recodex) and log (/var/log/recodex) directories to recodex user and group

It is supposed that your current working directory is that one with clonned worker source codes.

• Prepare environment running mkdir build && cd build
• Build sources by cmake .. following by make
• Build binary package by make package (may require root permissions). Note that rpm and deb packages are build in the same time. You may need to have rpmbuild command (usually as rpmbuild or rpm package) or edit CPACK_GENERATOR variable CMakeLists.txt file in root of source code tree.
• Install generated package through your package manager (yum, dnf, dpkg).

Note: If you do not want to generate binary packages, you can just install the project with make install (as root). But installation through your distribution's package manager is preferred way to keep your system clean and manageable in long term horizon.

Usage

Running broker is very similar to the worker setup. There is also provided systemd unit file for convenient usage. There is only one broker per whole ReCodEx solution, so there is no need for systemd templates.

• Running broker can be done by following command:

# systemctl start recodex-broker.service

Check with

# systemctl status recodex-broker.service

if the broker is running. You should see "active (running)" message.

• Broker can be stopped or restarted accordigly using systemctl stop and systemctl restart commands.
• If you want to run broker after system startup, run:

# systemctl enable recodex-broker.service

For further information about using systemd please refer to systemd documentation.

Fileserver

To install and use the fileserver, it is necessary to have Python3 with pip package manager installed. It is needed to install the dependencies. From clonned repository run the following command:

$ pip install -r requirements.txt

That is it. Fileserver does not need any special installation. It is possible to build and install rpm package or install it without packaging the same way as monitor, but it is only optional. The installation would provide you with script recodex-fileserver in you PATH. No systemd unit files are provided, because of the configuration and usage of fileserver component is much different to our other Python parts.

Configuration and usage

There are several ways of running the ReCodEx fileserver. We will cover three typical use cases.

Running in development mode

For simple development usage, it is possible to run the fileserver in the command line. Allowed options are described below.

usage: fileserver.py [--directory WORKING_DIRECTORY]
                     {runserver,shell} ...

• runserver argument starts the Flask development server (i.e. app.run()). As additional argument can be given a port number.
• shell argument instructs Flask to run a Python shell inside application context.

Simple development server on port 9999 can be run as

$ python3 fileserver.py runserver 9999

When run like this command, the fileserver creates a temporary directory where it stores all the files and which is deleted when it exits.

Running as WSGI script in a web server

If you need features such as HTTP authentication (recommended) or efficient serving of static files, it is recommended to run the app in a full-fledged web server (such as Apache or Nginx) using WSGI. Apache configuration can be generated by mkconfig.py script from the repository.

usage: mkconfig.py apache [-h] [--port PORT] --working-directory
                          WORKING_DIRECTORY [--htpasswd HTPASSWD]
                          [--user USER]

• port -- port where the fileserver should listen
• working_directory -- directory where the files should be stored
• htpasswd -- path to user file for HTTP Basic Authentication
• user -- user under which the server should be run

Running using uWSGI

Another option is to run fileserver as a standalone app via uWSGI service. Setup is also quite simple, configuration file can be also generated by mkconfig.py script.

1. (Optional) Create a user for running the fileserver

2. Make sure that your user can access your clone of the repository

3. Run mkconfig.py script.

   usage: mkconfig.py uwsgi [-h] [--user USER] [--port PORT]
                            [--socket SOCKET]
                            --working-directory WORKING_DIRECTORY
   

   • user -- user under which the server should be run
   • port -- port where the fileserver should listen
   • socket -- path to UNIX socket where the fileserver should listen
   • working_directory -- directory where the files should be stored

4. Save the configuration file generated by the script and run it with uWSGI, either directly or using systemd. This depends heavily on your distribution.

5. To integrate this with another web server, see the uWSGI documentation

Note that the ways distributions package uWSGI can vary wildly. In Debian 8 it is necessary to convert the configuration file to XML and make sure that the python3 plugin is loaded instead of python. This plugin also uses Python 3.4, even though the rest of the system uses Python 3.5 - make sure to install dependencies for the correct version.

Monitor

For monitor functionality there are some required packages. All of them are listed in requirements.txt file in the repository and can be installed by pip package manager as

$ pip install -r requirements.txt

Description of dependencies:

• zmq -- binding to ZeroMQ framework
• websockets -- framework for communication over WebSockets
• asyncio -- library for fast asynchronous operations
• pyyaml -- parsing YAML configuration files
• argparse -- parsing command line arguments

Installation will provide you following files:

• /usr/bin/recodex-monitor -- simple startup script located in PATH
• /etc/recodex/monitor/config.yml -- configuration file
• /etc/systemd/system/recodex-monitor.service -- systemd startup script
• code files will be installed in location depending on your system settings, mostly into /usr/lib/python3.5/site-packages/monitor/ or similar

Systemd script runs monitor binary as specific recodex user, so in postinst script user and group of this name are created. Also, ownership of configuration file will be granted to that user.

• RPM distributions can make and install binary package. This can be done like this:
  • run command

  $ python3 setup.py bdist_rpm --post-install ./install/postints
  

  to generate binary .rpm package or download precompiled one from releases tab of monitor GitHub repository (it is architecture independent package)
  • install package using

  # yum install ./dist/recodex-monitor-<version>-1.noarch.rpm
  

• Other Linux distributions can install cleaner straight

  $ python3 setup.py install --install-scripts /usr/bin
  # ./install/postinst
  

Usage

Preferred way to start monitor as a service is via systemd as the other parts of ReCodEx solution.

• Running monitor is fairly simple:

# systemctl start recodex-monitor.service

• Current state can be obtained by

# systemctl status recodex-monitor.service

You should see green Active (running).

• Setting up monitor to be started on system startup:

# systemctl enable recodex-monitor.service

Alternatively monitor can be started directly from command line with specifying path to configuration file. Note that this command will not start monitor as a daemon.

$ recodex-monitor -c /etc/recodex/monitor/config.yml

Cleaner

To install and use the cleaner, it is necessary to have Python3 with package manager pip installed.

• Dependencies of cleaner has to be installed:

$ pip install -r requirements.txt

• RPM distributions can make and install binary package. This can be done like this:

$ python setup.py bdist_rpm --post-install ./cleaner/install/postinst

#### Usage

As stated before cleaner should be cronned, on linux systems this can be done by
built in `cron` service or if there is `systemd` present cleaner itself provides
`*.timer` file which can be used for cronning from `systemd`. On Windows systems
internal scheduler should be used.

- Running cleaner from command line is fairly simple:

$ recodex-cleaner -c /etc/recodex/cleaner

- Enable cleaner service using systemd:

$ systemctl start recodex-cleaner.timer

- Add cleaner to linux cron service using following configuration line: 

0 0 * * * /usr/bin/recodex-cleaner -c /etc/recodex/cleaner/config.yml

- Add cleaner to Windows cheduler service with following command:

schtasks /create /sc daily /tn "ReCodEx Cleaner" /tr
""C:\Program Files\ReCodEx\cleaner\recodex-cleaner.exe"
-c "C:\Program Files\ReCodEx\cleaner\config.yml""

# yum install ./dist/recodex-cleaner-<version>-1.noarch.rpm

• Other Linux distributions can install cleaner straight

$ python setup.py install --install-scripts /usr/bin
# ./cleaner/install/postinst

• For Windows installation do following:
  • start cmd with administrator permissions
  • run installation with

  > python setup.py install --install-scripts \
    "C:\Program Files\ReCodEx\cleaner"
  

  where path specified with --install-scripts can be changed
  • copy configuration file alongside with installed executable using

  > copy install\config.yml \
    "C:\Program Files\ReCodEx\cleaner\config.yml"
  

REST API

The web API requires a PHP runtime version at least 7. Which one depends on actual configuration, there is a choice between mod_php inside Apache, php-fpm with Apache or Nginx proxy or running it as standalone uWSGI script. It is common that there are some PHP extensions, that have to be installed on the system. Namely ZeroMQ binding (php-zmq package or similar), MySQL module (php-mysqlnd package) and ldap extension module for CAS authentication (php-ldap package). Make sure that the extensions are loaded in your php.ini file (/etc/php.ini or files in /etc/php.d/).

The API depends on some other projects and libraries. For managing them Composer is used. It can be installed from system repositories or downloaded from the website, where detailed instructions are as well. Composer reads composer.json file in the project root and installs dependencies to the vendor/ subdirectory. To do that, run:

$ composer install

Database preparation

When the API is installed and configured (doctrine section is sufficient here) the database schema can be generated. There is a prepared command to do that from command line:

$ php www/index.php orm:schema-tool:update --force

With API comes some initial values, for example default user roles with proper permissions. To fill your database with these values there is another command line command:

$ php www/index.php db:fill

Check the outputs of both commands for errors. If there are any, try to clean temporary API cache in temp/cache/ directory and repeat the action.

Webserver configuration

The simplest way to get started is to start the built-in PHP server in the root directory of your project:

$ php -S localhost:4000 -t www

Then visit http://localhost:4000 in your browser to see the welcome page of API project.

For Apache or Nginx, setup a virtual host to point to the www/ directory of the project and you should be ready to go. It is critical that whole app/, log/ and temp/ directories are not accessible directly via a web browser (see security warning). Also it is highly recommended to set up a HTTPS certificate for public access to the API.

Troubleshooting

In case of any issues first remove the Nette cache directory temp/cache/ and try again. This solves most of the errors. If it does not help, examine API logs from log/ directory of the API source or logs of your webserver.

Web application

Web application requires NodeJS server as its runtime environment. This runtime is needed for executing JavaScript code on server and sending the pre-render parts of pages to clients, so the final rendering in browsers is a lot quicker and the page is accessible to search engines for indexing.

But some functionality is better in other full fledged web servers like Apache or Nginx, so the common practice is to use a tandem of both. NodeJS takes care of basic functionality of the app while the other server (Apache) is set as reverse proxy and providing additional functionality like SSL encryption, load balancing or caching of static files. The recommended setup contains both NodeJS and one of Apache and Nginx web servers for the reasons discussed above.

Stable versions of 4th and 6th series of NodeJS server are sufficient, using at least 6th series is highly recommended. Please check the most recent version of the packages in your distribution's repositories, there are often outdated ones. However, there are some third party repositories for all main Linux distributions.

The app depends on several libraries and components, all of them are listed in package.json file in source repository. For managing dependencies is used node package manager (npm), which can come with NodeJS installation otherwise can be installed separately. To fetch and install all dependencies run:

$ npm install

For easy production usage there is an additional package for managing NodeJS processes, pm2. This tool can run your application as a daemon, monitor occupied resources, gather logs and provide simple console interface for managing app's state. To install it globally into your system run:

# npm install pm2 -g

Usage

The application can be run in two modes, development and production. Development mode uses only client rendering and tracks code changes with rebuilds of the application in real time. In production mode the compilation (transpile to ES5 standard using Babel and bundle into single file using webpack) has to be done separately prior to running. The scripts for compilation are provided as additional npm commands.

• Development mode can be use for local testing of the app. This mode uses webpack dev server, so all code runs on a client, there is no server side rendering available. Starting is simple command, default address is http://localhost:8080.

$ npm run dev

• Production mode is mostly used on the servers. It provides all features such as server side rendering. This can be run via:

$ npm run build
$ npm start

Both modes can be configured to use different ports or set base address of used API server. This can be configured in .env file in root of the repository. There is .env-sample file which can be just copied and altered.

The production mode can be run also as a demon controled by pm2 tool. First the web application has to be built and then the server javascript file can run as a daemon.

$ npm run build
$ pm2 start bin/server.js

The pm2 tool has several options, most notably status, stop, restart and logs. Further description is available on project website.

Security

One of the most important aspects of ReCodEx instance is security. It is crucial to keep gathered data safe and not to allow unauthorized users modify restricted pieces of information. Here is a small list of recommendations to keep running ReCodEx instance safe.

• Secure MySQL installation. The installation script does not do any security actions, so please run at least mysql_secure_installation script on database computer.
• Get HTTPS certificate and set it in Apache for web application and API. Monitor should be proxied through the web server too with valid certificate. You can get free DV certificate from Let's Encrypt. Do not forget to set up automatic renewing!
• Hide broker, workers and fileserver behind firewall, private subnet or IPsec tunnel. They are not required to be reached from public internet, so it is better keep them isolated.
• Keep your server updated and well configured. For automatic installation of security updates on CentOS system refer to yum-cron package. Configure SSH and Apache to use only strong ciphers, some recommendations can be found here.
• Do not put actually used credentials on web, for example do not commit your passwords (in Ansible variables file) on GitHub.
• Regularly check logs for anomalies.