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Ansible Consul Role

consul is an ansible role which:

  • installs consul
  • configures consul
  • optionally installs and configures consul ui
  • optionally installs dnsmasq
  • optionally install consulate
  • optionally install consul-cli
  • configures consul service(s)

Installation

Using ansible-galaxy:

$ ansible-galaxy install savagegus.ansible-consul

Using arm (Ansible Role Manager):

$ arm install savagegus.consul

Using git:

$ git clone https://github.com/jivesoftware/ansible-consul.git

Variables

Here is a list of all the default variables for this role, which are also available in defaults/main.yml.

---
consul_version: 0.6.0
consul_archive: "consul_{{ consul_version }}_linux_amd64.zip"
consul_download: "https://releases.hashicorp.com/consul/{{ consul_version }}/{{ consul_archive }}"
consul_download_username: ""
consul_download_password: ""
consul_download_folder: /tmp

consul_is_ui: false
consul_ui_archive: "consul_{{ consul_version }}_web_ui.zip"
consul_ui_download: "https://releases.hashicorp.com/consul/{{ consul_version }}/{{ consul_ui_archive }}"
consul_ui_dir: "{{ consul_home }}/dist"
consul_ui_server_name: "{{ ansible_fqdn }}"
consul_ui_require_auth: false
consul_ui_nginx_template: "consul-nginx.conf.j2"
consul_ui_auth_user_file: /etc/htpasswd/consul
consul_ui_server_port: 80
consul_install_nginx: true
consul_install_nginx_config: true
consul_enable_nginx_config: true
consul_service_state: restarted

consul_install_consul_cli: false
consul_cli_archive: "master.zip"
consul_cli_download: "https://github.com/CiscoCloud/consul-cli/archive/{{ consul_cli_archive }}"

consul_home: /opt/consul
consul_config_dir: /etc/consul.d
consul_config_file: /etc/consul.conf
consul_log_file: /var/log/consul
consul_data_dir: "{{ consul_home }}/data"

consul_dns_allow_stale: false
consul_dns_max_stale: 5s
consul_dns_node_ttl: 0s
consul_dns_service_ttl: 0s
consul_dns_enable_truncate: false
consul_dns_only_passing: false
consul_recursors: []

consul_upstart_template: "consul.conf.j2"
consul_systemd_template: "consul.systemd.j2"
consul_initd_template: "consul.initd.sh.j2"
consul_dnsmasq_upstream_template: "resolv_dnsmasq.conf.j2"
consul_kv_template: "consulkv.j2"
consul_add_path_template: "consul.sh.j2"
consul_config_template: "consul.json.j2"

consul_binary: consul

consul_user: consul
consul_group: consul

consul_use_systemd: false
consul_use_upstart: true
consul_use_initd: false

consul_is_server: false

consul_domain: consul.

consul_servers: ['127.0.0.1']
consul_log_level: "INFO"
consul_syslog: false
consul_rejoin_after_leave: true
consul_leave_on_terminate: false

consul_join_at_start: false
consul_retry_join: false
consul_retry_interval: 30s
consul_retry_max: 0

consul_servers_wan: []
consul_join_wan: false
consul_retry_join_wan: false
consul_retry_interval_wan: 30s
consul_retry_max_wan: 0
consul_advertise_address_wan: false
consul_advertise_address: "127.0.0.1" - default: `undefined`. If this variable is not defined it is not set in the config
consul_bind_address: "0.0.0.0"
consul_dynamic_bind: false
consul_client_address: "127.0.0.1"

consul_client_address_bind: false
consul_datacenter: "default"
consul_disable_remote_exec: true

consul_port_dns: 8600
consul_port_http: 8500
consul_port_https: -1
consul_port_rpc: 8400
consul_port_serf_lan: 8301
consul_port_serf_wan: 8302
consul_port_server: 8300
consul_install_dnsmasq: false
consul_install_consulate: false
consul_dnsmasq:
  listen_interface:
    - lo
    - docker0
    - eth0
  no_dhcp_interface:
    - lo
    - docker0
    - eth0
  upstream_servers:
    - 8.8.8.8
    - 8.8.4.4
consul_node_name: "{{ inventory_hostname }}"
consul_verify_server_hostname: false
consul_cors_support: false
consul_disable_update_check: false

An instance might be defined through:

# enable ui
consul_is_ui: true
# start as a server
consul_is_server: true
# name datacenter
consul_datacenter: test
# bootstrap
consul_bootstrap: true
# name the node
consul_node_name: vagrant
# bind to ip
consul_bind_address: "{{ ansible_default_ipv4['address'] }}"
# encrypt using string from consul keygen
consul_encrypt: "X4SYOinf2pTAcAHRhpj7dA=="

Enable TLS encryption

See https://www.consul.io/docs/agent/encryption.html for details.

These files will be created on your Consul host:

consul_cert_file: "{{ consul_home }}/cert/consul.crt"
consul_key_file: "{{ consul_home }}/cert/consul.key"
consul_ca_file: "{{ consul_home }}/cert/ca.crt"

When you provide these vars. You should use Ansible Vault to encrypt these vars or perhaps pass them on the command line.

consul_tls_cert: |
  CERT CONTENTS HERE

consul_tls_key: |
  KEY CONTENTS HERE

consul_tls_ca_cert: |
  CERT CONTENTS HERE

Atlas Variables

consul_atlas_infrastructure: "your_infrastructure_name"
consul_atlas_token: "your_consul_token"

# if you want to use Atlas autodiscovery for clustering
consul_atlas_join: true

Telemetry Variables

Consul has excellent telemetry support. To enable it, use any of the following variables:

# if you want Consul to send metrics to a statsd instance
consul_statsd_address: "127.0.0.1:8125"
# if you want Consul to send metrics to a statsite instance
consul_statsite_address: "127.0.0.1:8125"
# this sets the prefix consul uses for all metrics
consul_statsite_prefix: "consul"
# if you don't want to prepend runtime telemetry with the machine's hostname (consul 0.6.4 or later)
consul_telemetry_disable_hostname: true

DNS Variables

Consul provides the ability to use it as a DNS resolver for service and node lookups. To enable dns_config with the below default values, set the consul_dns_config variable to true

consul_dns_allow_stale: false
consul_dns_max_stale: 5s
consul_dns_node_ttl: 0s
consul_dns_service_ttl: 0s
consul_dns_enable_truncate: false
consul_udp_answer_limit: 3
consul_dns_only_passing: false
consul_recursors:
  - 8.8.8.8
  - 8.8.4.4

Cross-origin Resource Sharing

Consul allows adding headers to the HTTP API responses, to enable CORS set the consul_cors_support variable to true

consul_cors_support: true

Shutdown behavior

Consul may be configured to perform (or not) cluster leave when it recieves TERM/INT signals.

When service is stopped:

  • systemd sends INT
  • init (init.d script) sends TERM
  • upstart sends TERM

There are two variables that define if the node will attempt cluster leave when it recieves those signals:

  • consul_leave_on_terminate defines if leave is performed when TERM is recieved. default: false
  • consul_skip_leave_on_interrupt defines if leave is not performed when INT is recieved. default: undefined. If this variable is not defined default consul behavior (which depends on version and server/agent role) will be used.

Handlers

These are the handlers that are defined in handlers/main.yml.

  • restart consul
  • restart dnsmasq
  • reload consul config
  • reload systemd

Example playbook that configures a Consul server on Ubuntu

---

- hosts: all
  vars:
    consul_is_server: "true"
    consul_datacenter: "test"
    consul_bootstrap: "true"
    consul_bind_address: "{{ ansible_default_ipv4['address'] }}"
  roles:
    - ansible-consul

Example playbook that configures a Consul server on Ubuntu with runit

- hosts: all
  vars:
    consul_reload_config_handler: runit reload consul
    consul_restart_handler: runit restart consul
    consul_log_file: /dev/null
  roles:
    - ansible-consul
    - role: runit
      runit_pre_start_command: "setcap CAP_NET_BIND_SERVICE=+eip /opt/consul/bin/consul"
      runit_service_command: "/opt/consul/bin/consul"
      runit_service_params: "agent -config-dir /etc/consul.d -config-file=/etc/consul.conf"
      runit_service_env:
        GOMAXPROCS: "{{ ansible_processor_vcpus }}"

Logs will be handled by runit and consul_log_file set to /dev/null just to prevent /var/log/consul file creation as it conflicts with runit logs directory.

Example playbooks that configures a Consul server on CentOS 7

---

- hosts: all
  vars:
    consul_is_server: "true"
    consul_datacenter: "test"
    consul_bootstrap: "true"
    consul_bind_address: "{{ ansible_default_ipv4['address'] }}"
    consul_use_upstart: false
    consul_use_systemd: true
    nginx_user: "nginx"
  roles:
    - ansible-consul

Example to register consul services

consul_services:
  - service:
      name: "redis localhost"
      tags:
        - "redis"
      address: "127.0.0.1"
      port: 6379
      checks:
        - name: "Redis health check"
          tcp: "localhost:6379"
          interval: "10s"
          timeout: "1s"

Testing

$ git clone https://github.com/jivesoftware/ansible-consul.git
$ cd ansible-consul
$ ansible-galaxy install --role-file=requirements.yml --roles-path=roles --force
$ vagrant up

or use the TestKitchen tests

$ bundle
$ rm -rf roles
$ bundle exec kitchen test

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests and examples for any new or changed functionality.

  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request

License

Copyright (c) Matthew Finlayson under the Apache license.