lsyncd
Lsyncd Configurations
Overview
This Ansible role configures synchronization from master host to slave host(s). Lsyncd daemon on master is responsible for synchronization. There's only one master whereas there can be more than one slaves. There can also be more than one synchronizing sources (on master) and targets (on slave).
On master, the lsyncd daemon is running as root. On slaves, a dedicated lsyncd user is created. This user is capable of executing sudo rsync so that synced files can have permissions preserved. When synchronizing, root ssh into slaves as lsyncd user and executing rsync command there.
Because lsyncd is running in the background, a passwordless SSH key pair is generated for root on master. The corresponding public key is dispatched to every slave.
On master, lsyncd status file locates at /var/lib/lsyncd/status, lsyncd log locates at /var/log/lsyncd.log. You should check these files regularly in case of possible problems.
This role has been successfully tested on Debian Jessie (8.x), Debian Stretch (9.x) and Ubuntu Trusty (14.04), Ubuntu Xenial (16.04).
Role Variables
lsyncd_inotify_max_watches: 65536
The maximum possible number of directories lsyncd watches. This is a Linux kernel limit (fs.inotify.max_user_watches) which defaults to 8192 on Debian. Consider raise this number when lsyncd is watching huge number of files.
lsyncd_master_hostname:
The hostname of the master. Should be one inventory_hostname in inventory. There's only one master. See example below.
lsyncd_master_identity_file: /root/.ssh/id_rsa_lsyncd
The filename of root user's SSH private key on master. A new key pair will be generated if the file doesn't exist.
lsyncd_slave_hosts: []
A list of FQDN or IP address of slave hosts. There can be multiple slaves.
lsyncd_slave_username: lsyncd
The username on the slaves which master uses to login via SSH.
lsyncd_sources_and_targets: []
A list of sources on master which are to sync with targets on slaves. There can be multiple source and target pairs. See example below.
lsyncd_settings_status_interval: 10
lsyncd_sync_delay: 15
Lsyncd fine tuning parameters. Don't change these unless you know what you are doing.
Dependencies
This role has no dependencies.
Example Playbook
First prepare an inventory. We use the following inventory in our example.
[lsyncd]
test1 ansible_host=10.0.0.1 ansible_user=root
test2 ansible_host=10.0.0.2 ansible_user=root
test3 ansible_host=10.0.0.3 ansible_user=root
Note that Ansible inventory_hostname variables are test1, test2 and test3 for this inventory. One of them must be the master host. We choose test1 as our master. The other two will serve as slavs.
Here's an example playbook.
- hosts: lsyncd
vars:
lsyncd_master_hostname: test1
lsyncd_slave_hosts:
- 10.0.0.2
- 10.0.0.3
lsyncd_sources_and_targets:
- source: /var/www
target: /var/www
- source: /home
target: /backup/home
roles:
- { role: hanru.lsyncd }
License
MIT