Consul

This Ansible role performs basic Consul installation, including filesystem structure, and example configuration.

It can also bootstrap a minimal development or evaluation cluster of 3 server agents running in a Vagrant and VirtualBox based environment. See README_VAGRANT.md and the associated Vagrantfile for more details about the developer mode setup.

Requirements

This role requires a Debian or RHEL based Linux distribution. It might work with other software versions, but does work with the following specific software and versions:

• Ansible: 2.2.0.0
• Consul: 0.7.0
• Debian: 8
• CentOS: 7

Role Variables

The role defines variables in defaults/main.yml and in the hosts inventory file (see below):

Name	Default Value	Description
consul_version	0.7.0	Version to install
consul_zip_url	https://releases.hashicorp.com/consul/{{ consul_version }}/consul_{{ consul_version }}_linux_amd64.zip	Download URL
consul_zip_sha256	SHA256 SUM	Archive SHA256 summary
consul_bin_path	/usr/local/bin	Binary installation path
consul_config_path	/etc/consul.d	Configuration file path
consul_data_path	/var/consul	Data path
consul_log_path	/var/log/consul	Log path
consul_user	consul	OS user
consul_group	bin	OS group
consul_group_name	cluster_nodes	Inventory group name
consul_datacenter	dc1	Datacenter label
consul_domain	consul	Consul domain name
consul_log_level	INFO	Log level
consul_syslog_enable	true	Log to syslog
consul_iface	eth1	Consul network interface
consul_bind_address	127.0.0.1	Bind address
consul_bootstrap_address	{{ hostvars[groups[consul_group_name][0]]['ansible_'+consul_iface]['ipv4']['address'] }}	The server interface that additional server nodes will join to for bootstrapping
consul_dns_bind_address	127.0.0.1	DNS API bind address
consul_http_bind_address	0.0.0.0	HTTP API bind address
consul_https_bind_address	0.0.0.0	HTTPS API bind address
consul_rpc_bind_address	0.0.0.0	RPC bind address
consul_node_name	{{ inventory_hostname_short }}	Node name (should not include dots)
consul_recursors	Empty list	List of upstream DNS servers — see recursors
consul_bind_address	dynamic from hosts inventory	The interface address to bind to
consul_dnsmasq_enable	false	Whether to install and configure DNS API forwarding on port 53 using dnsmasq
consul_iptables_enable	false	Whether to enable iptables rules for Consul
consul_acl_enable	false	Enable ACLs
consul_acl_datacenter	dc1	ACL authoritative datacenter name
consul_acl_default_policy	allow	Default ACL policy
consul_acl_down_policy	allow	Default ACL down policy
consul_acl_master_token	UUID	ACL master token
consul_acl_master_token_display	false	Display generated ACL Master Token
consul_acl_replication_token	UUID	ACL replication token
consul_atlas_enable	false	Enable Atlas support
consul_atlas_infrastructure	Environment variable	Atlas infrastructure name
consul_atlas_token	Environment variable	Atlas token

Host Inventory Variable

This role also uses a host inventory variable to define the server's role when forming a cluster. One server should be designated as the bootstrap server that uses the bootstrap_expect configuration directive, and the other servers will connect to this server. You can also specify client as the role, and Consul will be configured as a client agent instead of a server.

Name	Default Value	Description
consul_node_role	NONE	Consul server role, one of: bootstrap, server, or client

Here is an example of how the hosts inventory could be defined for a simple cluster of 3 servers:

consul1.local consul_node_role=bootstrap 
consul2.local consul_node_role=server
consul3.local consul_node_role=server

OS Distribution Variables

The consul binary works on most Linux platforms and is not distribution specific. However, some distributions require installation of specific OS packages with different package names.

Name	Default Value	Description
consul_centos_pkg	{{ consul_version }}_linux_amd64.zip	Consul package filename
consul_centos_url	{{ consul_zip_url }}	Consul package download URL
consul_centos_sha256	SHA256 SUM	Consul download SHA256 summary
consul_centos_os_packages	list	List of OS packages to install
consul_debian_pkg	{{ consul_version }}_linux_amd64.zip	Consul package filename
consul_debian_url	{{ consul_zip_url }}	Consul package download URL
consul_debian_sha256	SHA256 SUM	Consul download SHA256 summary
consul_debian_os_packages	list	List of OS packages to install
consul_redhat_pkg	{{ consul_version }}_linux_amd64.zip	Consul package filename
consul_redhat_url	{{ consul_zip_url }}	Consul package download URL
consul_redhat_sha256	SHA256 SUM	Consul download SHA256 summary
consul_redhat_os_packages	list	List of OS packages to install
consul_ubuntu_pkg	{{ consul_version }}_linux_amd64.zip	Consul package filename
consul_ubuntu_url	{{ consul_zip_url }}	Consul package download URL
consul_ubuntu_sha256	SHA256 SUM	Consul download SHA256 summary
consul_ubuntu_os_packages	list	List of OS packages to install

Dependencies

Ansible requires GNU tar and this role performs some local use of the unarchive module, so ensure that your system has gtar installed and in the PATH.

If you're on system with a different (i.e. BSD) tar, like macOS and you see odd errors during unarchive tasks, you could be missing gtar.

Example Playbook

Basic installation is possible using the included site.yml playbook:

ansible-playbook -i hosts site.yml

You can also pass variables in using the --extra-vars option to the ansible-playbook command:

ansible-playbook -i hosts site.yml --extra-vars "consul_datacenter=maui"

Be aware that for clustering, the included site.yml does the following:

1. Executes consul role (installs Consul and bootstraps cluster)
2. Reconfigures bootstrap node to run without bootstrap-expect setting
3. Restarts bootstrap node

ACL Support

Basic support for ACLs is included in the role. You can set the environment variables CONSUL_ACL_ENABLE to true, and also set the CONSUL_ACL_DATACENTER environment variable to its correct value for your environment prior to executing your playbook; for example:

CONSUL_ACL_ENABLE=true CONSUL_ACL_DATACENTER=maui \
CONSUL_ACL_MASTER_TOKEN_DISPLAY=true ansible-playbook -i uat_hosts aloha.yml

If you want the automatically generated ACL Master Token value emitted to standard out during the play, set the environment variable CONSUL_ACL_MASTER_TOKEN_DISPLAY to true as in the above example.

There are a number of Ansible ACL variables you can override to further refine your initial ACL setup. They are not all currently picked up from environment variables, but do have some sensible defaults. Check defaults/main.yml to see how some of he defaults (i.e. tokens) are automatically generated.

Atlas Support

Basic support for Atlas is included in the role. You can set the environment variables CONSUL_ATLAS_ENABLE to true, and also set the CONSUL_ATLAS_INFRASTRUCTURE and CONSUL_ATLAS_TOKEN environment variables to their correct values for your environment prior to executing your playbook; for example:

CONSUL_ATLAS_ENABLE=true CONSUL_ATLAS_INFRASTRUCTURE=brianshumate/example \
CONSUL_ATLAS_TOKEN=00000000-000000000-000000000000-0000 \
ansible-playbook -i uat_hosts site.yml

Dnsmasq Forwarding Support

The role now includes support for DNS forwarding with Dnsmasq.

Enable like this:

ansible-playbook -i hosts site.yml --extra-vars "consul_dnsmasq_enable=true"

Then, you can query any of the agents via DNS directly via port 53, for example:

dig @consul1.local consul3.node.consul

; <<>> DiG 9.8.3-P1 <<>> @consul1.local consul3.node.consul
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29196
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;consul3.node.consul.   IN  A

;; ANSWER SECTION:
consul3.node.consul.  0 IN  A 10.1.42.230

;; Query time: 42 msec
;; SERVER: 10.1.42.210#53(10.1.42.210)
;; WHEN: Sun Aug  7 18:06:32 2016
;;

Vagrant and VirtualBox

See examples/README_VAGRANT.md for details on quick Vagrant deployments under VirtualBox for testing, etc.

License

BSD

Author Information

Brian Shumate

Contributors

Special thanks to the folks listed in CONTRIBUTORS.md for their contributions to this project.