Ansible for CMS

This repository provides basic ansible playbooks to conveniently

• deliver CMS and isolate configuration files to contest servers,
• start a specific contest on them (this assumes you have configured systemd services for CMS) and
• restart cms-resource.service.

Prerequisites

Ansible allows to run pre-configured instructions on servers, including copying files there, modifying remote files, or running remote commands. The instructions to run are configured in yaml configuration files called playbooks. The servers (hosts) are listed in what is called an inventory file.

Ansible is included in just about any Linux distribution and can most likely be installed with your package manager.

Simple host configuration

In a simple one-server configuration like in the German selection for the IOI, the inventory file will just consist of that single server (host). So, if you are one of the German coaches, it suffices to put the following in a file hosts:

[email protected] ansible_user=root ansible_python_interpreter=auto_silent

copy_configs.yaml

This playbook will copy a set of configuration files from your machine to the host(s). Note that as-is, it always writes four configuration files at once: cms.conf, cms.ranking.conf, isolate and an nginx site put under /etc/nginx/sites-available/ with the name of the file you provide. Therefore, you will need to have and provide all of the right configuration files locally. The previous files on the hosts will be copied to backup files.

You can use this playbook as follows, where [path] is the local path to the configuration files.

ansible-playbook copy_configs.yaml \
                 -i hosts \
                 -e "cmsconf=[path]/cms.conf cmsrankingconf=[path]/cms.ranking.conf isolate=[path]/isolate cmsnginxconf=[path]/cms"

Note that this will not create a link to the nginx site file from sites-enabled. You will need to create it manually if you want the nginx site to be available and have not done so already.

⚠️ This playbook does not (re)start any services. You need to do that yourself when appropriate.

start_contest.yaml

This playbook will change the host's /home/cms/resource-service.conf (this path may need to be adapted for your server) file with the contest_id you provide. If it has changed, it then restarts cms-resource.service. This will usually be the appropriate way to ensure a certain contest (or the all-contests mode) is running.

You can use this playbook as follows, where [id] is the ID of the contest you want to start, or ALL if you want to start the all-contests mode.

ansible-playbook start_contests.yaml \
                 -i hosts \
                 -e "contest_id=[id]"

Alternatively, you can run ansible-playbook start_contests.yaml -i hosts and will be prompted for the contest id.

⚠️ If the CONTEST_ID has not changed on the host and cms-resource.service was not running before, this command will not start it! You can use restart_resource.yaml in that case.

restart_resource.yaml

This playbook restarts the cms-resource.service.

You can use this playbook as follows.

ansible-playbook restart_resource.yaml \
                 -i hosts

TODO

• Provide a convenient way to select the contest to start with start_contest.yaml. Currently, you have to guess or already know the ID of the contest, or run and cancel the script beforehand to find out.
• Let copy_configs.yaml have an option to change only some configuration files. Perhaps by ignoring them if an empty path was provided.
• Let copy_configs.yaml restart services as appropriate, perhaps after a prompt.
• Let start_contest.yaml show a prompt if it should (re)start cms-resource.service even though contest_id has not changed.