Introduction

In this fifth article in the DevOps series we will learn to install and set up Graphite using Ansible. Graphite is a monitoring tool that was written by Chris Davis in 2006. It has been released under the Apache 2.0 license and comprises three components:

Graphite-Web
Carbon
Whisper

Graphite-Web is a Django application and provides a dashboard for monitoring. Carbon is a server that listens to time-series data, while Whisper is a database library for storing the data.

Setting it up

A CentOS 6.8 Virtual Machine (VM) running on KVM is used for the installation. Please make sure that the VM has access to the Internet. The Ansible version used on the host (Parabola GNU/Linux-libre x86_64) is 2.2.1.0. The ansible/ folder contains the following files:

ansible/inventory/kvm/inventory
ansible/playbooks/configuration/graphite.yml
ansible/playbooks/admin/uninstall-graphite.yml

The IP address of the guest CentOS 6.8 VM is added to the inventory file as shown below:

graphite ansible_host=192.168.122.120 ansible_connection=ssh ansible_user=root ansible_password=password

Also, add an entry for the graphite host in /etc/hosts file as indicated below:

192.168.122.120 graphite

Graphite

The playbook to install the Graphite server is given below:

---
- name: Install Graphite software
  hosts: graphite
  gather_facts: true
  tags: [graphite]

  tasks:
    - name: Import EPEL GPG key
      rpm_key:
        key: http://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-6
        state: present

    - name: Add YUM repo
      yum_repository:
        name: epel
        description: EPEL YUM repo
        baseurl: https://dl.fedoraproject.org/pub/epel/$releasever/$basearch/
        gpgcheck: yes

    - name: Update the software package repository
      yum:
        name: '*'
        update_cache: yes

    - name: Install Graphite server
      package:
        name: "{{ item }}"
        state: latest
      with_items:
        - graphite-web

We first import the keys for the Extra Packages for Enterprise Linux (EPEL) repository and update the software package list. The ‘graphite-web’ package is then installed using Yum. The above playbook can be invoked using the following command:

$ ansible-playbook -i inventory/kvm/inventory playbooks/configuration/graphite.yml --tags "graphite"

MySQL

A backend database is required by Graphite. By default, the SQLite3 database is used, but we will install and use MySQL as shown below:

- name: Install MySQL
  hosts: graphite
  become: yes
  become_method: sudo
  gather_facts: true
  tags: [database]

  tasks:
    - name: Install database
      package:
        name: "{{ item }}"
        state: latest
      with_items:
        - mysql
        - mysql-server
        - MySQL-python
        - libselinux-python

    - name: Start mysqld server
      service:
        name: mysqld
        state: started

    - wait_for:
        port: 3306

    - name: Create graphite database user
      mysql_user:
        name: graphite
        password: graphite123
        priv: '*.*:ALL,GRANT'
        state: present

    - name: Create a database
      mysql_db:
        name: graphite
        state: present

    - name: Update database configuration
      blockinfile:
        path: /etc/graphite-web/local_settings.py
        block: |
          DATABASES = {
            'default': {
            'NAME': 'graphite',
            'ENGINE': 'django.db.backends.mysql',
            'USER': 'graphite',
            'PASSWORD': 'graphite123',
           }
          }

    - name: syncdb
      shell: /usr/lib/python2.6/site-packages/graphite/manage.py syncdb --noinput

    - name: Allow port 80
      shell: iptables -I INPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT

    - name:
      lineinfile:
        path: /etc/httpd/conf.d/graphite-web.conf
        insertafter: '           # Apache 2.2'
        line: '           Allow from all'

    - name: Start httpd server
      service:
        name: httpd
        state: started

As a first step, let’s install the required MySQL dependency packages and the server itself. We then start the server and wait for it to listen on port 3306. A graphite user and database is created for use with the Graphite Web application. For this example, the password is provided as plain text. In production, use an encrypted Ansible Vault password.

The database configuration file is then updated to use the MySQL credentials. Since Graphite is a Django application, the manage.py script with syncdb needs to be executed to create the necessary tables. We then allow port 80 through the firewall in order to view the Graphite dashboard. The graphite-web.conf file is updated to allow read access, and the Apache web server is started.

The above playbook can be invoked as follows:

$ ansible-playbook -i inventory/kvm/inventory playbooks/configuration/graphite.yml --tags "database"

Carbon and Whisper

The Carbon and Whisper Python bindings need to be installed before starting the carbon-cache script.

- name: Install Carbon and Whisper
  hosts: graphite
  become: yes
  become_method: sudo
  gather_facts: true
  tags: [carbon]

  tasks:
    - name: Install carbon and whisper
      package:
        name: "{{ item }}"
        state: latest
      with_items:
        - python-carbon
        - python-whisper

    - name: Start carbon-cache
      shell: /etc/init.d/carbon-cache start

The above playbook is invoked as follows:

$ ansible-playbook -i inventory/kvm/inventory playbooks/configuration/graphite.yml --tags "carbon"

Dashboard

You can open http://192.168.122.120 in the browser on the host to view the Graphite dashboard. A screenshot of the Graphite web application is shown below:

Uninstall

An uninstall script to remove the Graphite server and its dependency packages is required for administration. The Ansible playbook for the same is available in playbooks/admin folder and is given below:

---
- name: Uninstall Graphite and dependencies
  hosts: graphite
  gather_facts: true
  tags: [remove]

  tasks:
    - name: Stop the carbon-cache server
      shell: /etc/init.d/carbon-cache stop

    - name: Uninstall carbon and whisper
      package:
        name: "{{ item }}"
        state: absent
      with_items:
        - python-whisper
        - python-carbon

    - name: Stop httpd server
      service:
        name: httpd
        state: stopped

    - name: Stop mysqld server
      service:
        name: mysqld
        state: stopped

    - name: Uninstall database packages
      package:
        name: "{{ item }}"
        state: absent
      with_items:
        - libselinux-python
        - MySQL-python
        - mysql-server
        - mysql
        - graphite-web

The script can be invoked as follows:

$ ansible-playbook -i inventory/kvm/inventory playbooks/admin/uninstall-graphite.yml

References

Graphite documentation. https://graphite.readthedocs.io/en/latest/
Carbon. https://github.com/graphite-project/carbon
Whisper database. http://graphite.readthedocs.io/en/latest/whisper.html

2017 devops