nats_cluster

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NATS cluster ansible role

Molecule

This role installs and configures NATS cluster. Gateways and Leaf nodes are partially supported.

Important notes:

  • It's not clear what configuration changes can be 'reloaded' and what require restart so now all changes lead to restart;

  • If something is not clear in variables description below please check values for molecule tests as a sample how these variables can be used;

Requirements

There are no special requirements.

Role Variables

Variable Description Default value
nats_version Version of NATS server 2.9.11
nats_user System user to run NATS server nats
nats_group System group to run NATS server nats
nats_host Host for client connections 0.0.0.0
nats_port Port for client connections 4222
nats_port_http HTTP port for server monitoring 8222
nats_server_name NATS server name {{ ansible_fqdn }}
nats_log_enabled Enable logging true
nats_log_dir Logs directory /var/log/nats
nats_log_file Log file path nats-server.log
nats_log_rotate Maximum log files to keep 7
nats_log_debug Enable debug logging false
nats_max_payload Maximum number of bytes in a message payload 1MB
nats_auth_type NATS authentication type. Possible values are none, token and password. See details below. none
nats_auth_token Token value for nats_auth_type=token secret
nats_users Dictionary of NATS users. See details below {}
nats_default_permissions Default permissions for users don't have specific permissions set {}
nats_sys_account_user Special user to manage system events (nats server commands family requires it to be defined). This user should be defined in nats_users dictionary (see above) and has configured account N/A
nats_no_auth_user Which user is used for connections without any authentication. It's potential security breach and should be used carefully N/A
nats_cluster_host_group Ansible host group name contains hosts from NATS cluster. This provides ability to configure several clusters in one play (see molecule tests as a reference) nats
nats_cluster_address Interface where the host will listen for incoming route connections {{ ansible_default_ipv4.address }}
nats_cluster_port Port where the host will listen for incoming route connections 6222
nats_cluster_user Username to establish connections between hosts in the cluster cluster
nats_cluster_password Password to establish connections between hosts in the cluster password
nats_cluster_gateway_host_groups Ansible host group name contains hosts from an another NATS cluster which will be used as gateways []
nats_cluster_gateway_port Port where the gateway will listen for incoming gateway connections 7222
nats_cluster_gateway_user Username to establish connections between gateway gateway
nats_cluster_gateway_password Password to establish connections between gateway password
nats_leaf_node_port Port where the server will listen for incoming leaf node connections 7422
nats_leaf_node_listen_enabled Is host listen for incoming leaf nodes connection. Mutually exclusive with nats_leaf_node_remotes below false
nats_leaf_node_remotes Remote addresses of hosts accepting incoming leaf nodes connections. This enables leaf node if not empty. Only one endpoint for each remote cluster should be used []
nats_jetstream_enabled Enable JetStream. This option has "global" effect and JetStream will be enabled for all accounts. There is no way now to configure JetStream account's options false
nats_jetstream_storage_dir Directory to use for JetStream storage /var/lib/nats/jetstream
nats_jetstream_max_memory Maximum size of the 'memory' storage 1G
nats_jetstream_max_storage_file_size Maximum size of the 'file' storage 10G
nats_cli_install Installs NATS CLI false
nats_cli_version NATS CLI version 0.0.35
nats_exporter_enabled Installs NATS Prometheus exporter false
nats_exporter_version NATS Prometheus exporter version 0.10.1
nats_exporter_options NATS Prometheus exporter command line options -port 7777 -channelz -connz -routez -serverz -subz -varz

nats_auth_type

Token and password authentications are mutually exclusive and when nats_auth_type=token users and accounts related configuration (nats_users dictionary and all cluster/gateway user and password variables) doesn't make sense.

When nats_auth_type=password it's not required to provide nats_users but cluster/gateway related variables have defaults so it's authentication will be enabled.

nats_users

Users can be configured for authorization and accounts with an appropriate permissions, for example:

    nats_users:
        foo:
            password: foo
            permissions:
                publish:
                    - "SANDBOX.*"
                subscribe:
                    - "PUBLIC.>"
                    - "_INBOX.>"
        bar:
            account: BAR
            password: bar

User foo above doesn't have account and will be presented in authorization section. There is account for user bar so it will be in accounts.

Example Playbook

Playbooks below install NATS cluster on all nodes in dc1 group with token authorization for clients.

- name: install NATS cluster
  hosts: dc1
  vars:
    nats_auth_type: 'token'
    nats_auth_token: 's3cr3t'
    nats_cluster_host_group: dc1
    nats_cluster_user: cluster
    nats_cluster_password: changeit
  roles:
    - role: oukooveu.nats_cluster

Molecule tests

To run tests locally:

python -m venv .venv
. .venv/bin/activate
pip install -r molecule/default/requirements.txt
molecule test

To run tests for non-default image (debian:10) set MOLECULE_IMAGE environment variable to an appropriate value, for example:

export MOLECULE_IMAGE=rockylinux:8

If you just want to run NATS (two clusters and leaf node) this can be done by changing last command to molecule converge.

To cleanup test environment run molecule destroy.

License

Apache 2.0

About

Role for NATS cluster

role nats messaging cluster
Install
ansible-galaxy install oukooveu/ansible-role-nats-cluster
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