stone-payments.mongodb

Role for Ansible which manages MongoDB in a standalone setup or replica set.

Supported systems

To conserve development efforts, we decided that a supported distro should:

• be currently supported by the distro-maker (aka not in EOL);
• be currently supported by MongoDB.org (this requirement will probably be dropped soon);
• be systemd-based;
• have a wide-enough user-base.

Therefore, the supported systems list is currently:

• Enterprise Linux (both CentOS and RHEL)
  • 7.3
  • 7.4
  • 7.5
• Ubuntu
  • 16.04

Further distros may be added upon request, as long as the requirements are met.

Usage

Quickstart

There's absolute no variable needed to setup a basic, passwordless, loopback-only, standalone MongoDB setup. Just include it in a play:

- name: install mongodb
  hosts: all
  roles: stone-payments.mongodb

Replica set setup

In order to build a replica set, you need to inform the master that he is a master, and a replica on which master to connect to. You can do all this with the following excerpt:

- name: install mongodb replica set
  host: all
  roles: stone-payments.mongodb
  vars:
    mongodb_conf_bindIp: "0.0.0.0"
    mongodb_replSet_enabled: true
    mongodb_replSet_name: "someReplicaSetName"
    mongodb_replSet_master: "1.2.3.4" #must be an IP address
    mongodb_replSet_key: "someLongKey" #optional, cross-replica authentication key
    mongodb_replSet_member: "{{ ansible_eth1['ipv4']['address'] }}" #optional, specify a different IF for replication
    mongodb_replSet_arbiter: "{{ true if inventory_hostname == 'hostThatIsArbiter' else false }}"

Authentication

You can enable authentication and create an admin account the following way:

- name: install mongodb with authentication
  hosts: all
  roles: stone-payments.mongodb
  vars:
    mongodb_conf_auth: true
    mongodb_admin_user: "admin"
    mongodb_admin_password: "somePassword"

Logging

You can set any systemLog option by providing mongodb_conf_logging dictionary:

- name: install mongodb with network debug logging
  host: all
  roles: stone-payments.mongodb
  vars:
    mongodb_conf_logging:
      verbosity: 0
      component:
        network:
          verbosity: 5
      destination: file
      path: /var/log/mongodb/mongod.log

Firewall

This rule will configure either ufw or firewalld to enable incoming connections by default. You may customize this with the following options (which are specific to the firewall solution you're utilizing):

- name: install mongodb with custom firewall settings
  hosts: all
  roles: stone-payments.mongodb
  vars:
    mongodb_firewall_zone: "public" #firewalld only
    mongodb_firewall_interface: "eth0" #ufw only
    mongodb_firewall_source: "192.168.0.0/24" #ufw only

You may also suppress firewall config by setting mongodb_install_firewall: false.

Linux Security Modules

This role will configure LSMs by default (currently only SELinux is supported). You may disable this by setting: mongodb_install_lsm: false.

Other configs

I believe almost every other config is self-explanatory or directly related to a MongoDB core feature. Simply override the configs on defaults/main.yml and they will be (hopefully) applied to your system.

Testing

This role implements most unit tests with Molecule on Docker. Notice that we only support Molecule 2.0 or greater. Some tests are implemented on Vagrant with VirtualBox so we can test aspects that require a full-blown VM. However, for the tests that require Vagrant, there's no CI integration since there isn't a public CI that supports nested virtualization.

The following scenarios are present:

Docker environment setup

You can install Molecule and the Docker interaction library inside a virtual environment with the following commands. Notice that we need docker-py both inside and outside the virtualenv.

sudo pip install docker-py
virtualenv .venv
.venv/bin/activate
pip install molecule docker-py

The Docker installation and configuration is out of scope.

If you have a SELinux-enabled host, you must also have the libselinux-python library installed. There's a special addition in the Molecule playbook when delegating tasks to localhost to use the host's python interpreter instead of the virtualenv python in order to properly access the SELinux bindings. You can install this package both on Fedora and CentOS with:

sudo yum install python2-libselinux

Vagrant environment setup

You can install Molecule inside a virtual environment with the following commands:

virtualenv .venv
.venv/bin/activate
pip install molecule

The Vagrant and VirtualBox installation and configuration is out of scope.

Running the test

After having Molecule setup within the virtualenv, you can run the tests with:

molecule converge [-s scenario_name]

Where scenario_name is the name of a test case under molecule. The default test case is run if no parameter is passed.

Contributing

Just open a PR. We love PRs!

To Do List

Here's some suggestions on what to do:

• Support use of distro-packaged MongoDB.
• Write further standalone tests with serverspec or testinfra.
• Improve the test case for the replica set.

License

This role is distributed under the MIT license.