Puppet agent is the application that manages the configurations on your nodes. It requires a Puppet master to fetch configuration catalogs from.
Depending on your infrastructure and needs, you can manage systems with Puppet agent as a service, as a cron job, or on demand.
For more information about running the puppet agent command, see the puppet agent man page.
Puppet agent's run environment
Puppet agent runs as a specific user, (usually root) and initiates outbound connections on port 8140.
Ports
Puppet’s HTTPS traffic uses port 8140. Your operating system and firewall must allow Puppet agent to initiate outbound connections on this port.
If you want to use a non-default port, you have to change the masterport setting on all agent nodes, and ensure that you change your Puppet master’s port as well.
User
Puppet agent runs as root, which lets it manage the configuration of the entire system.
Puppet agent can also run as a non-root user, as long as it is started by that user. However, this restricts the resources that Puppet agent can manage, and requires you to run Puppet agent as a cron job instead of a service.
If you need to install packages into a directory controlled by a non-root user, use an exec to unzip a tarball or use a recursive file resource to copy a directory into place.
When running without root permissions, most of Puppet’s resource providers cannot use sudo to elevate permissions. This means Puppet can only manage resources that its user can modify without using sudo.
| Resource type | Details |
|---|---|
augeas | |
cron | Only non-root cron jobs can be viewed or set. |
exec | Cannot run as another user or group. |
file | Only if the non-root user has read/write privileges. |
notify | |
schedule | |
service | For services that don’t require root. You can also use the start, stop, and status attributes to specify how non-root users can control the service. |
ssh_authorized_key | |
ssh_key |
Manage systems with Puppet agent
In a standard Puppet configuration, each node periodically does configuration runs to revert unwanted changes and to pick up recent updates.
- Run Puppet agent as a service.
- The easiest method. The Puppet agent daemon does configuration runs at a set interval, which can be configured.
- Make a cron job that runs Puppet agent.
- Requires more manual configuration, but a good choice if you want to reduce the number of persistent processes on your systems.
- Only run Puppet agent on demand.
- You can also deploy MCollective to run on demand on many nodes.
Choose whichever one works best for your infrastructure and culture.
Run Puppet agent as a service
The puppet agent command can start a long-lived daemon process that does configuration runs at a set interval.
Run Puppet agent as a cron job
Run Puppet agent as a cron job when running as a non-root user.
If the onetime setting is set to true, the Puppet agent command does one configuration run and then quits. If the daemonize setting is set to false, the command stays in the foreground until the run is finished. If set to true, it does the run in the background.
This behavior is good for building a cron job that does configuration runs. You can use the splay and splaylimit settings to keep the Puppet master from getting overwhelmed, because the system time is probably synchronized across all of your agent nodes.
puppet resource command: Run Puppet agent on demand
Some sites prefer to run Puppet agent on-demand, and others use scheduled runs along with the occasional on-demand run.
You can start Puppet agent runs while logged in to the target system, or remotely with Bolt or MCollective.
To run remotely on multiple machines, you need some form of orchestration or parallel execution tool, such as Bolt or MCollective with the puppet agent plugin.
Disable and re-enable Puppet runs
Whether you’re troubleshooting errors, working in a maintenance window, or developing in a sandbox environment, you might need to temporarily disable the Puppet agent from running.
Configuring Puppet agent
The Puppet agent comes with a default configuration that you might want to change.
Configure Puppet agent with puppet.conf using the [agent] section, the [main] section, or both. For information on settings relevant to Puppet agent, see important settings.
Logging for Puppet agent on *nix systems
When running as a service, Puppet agent logs messages to syslog. Your syslog configuration determines where these messages are saved, but the default location is /var/log/messages on Linux, /var/log/system.log on Mac OS X, and /var/adm/messages on Solaris.
You can adjust how verbose the logs are with the log_level setting, which defaults to notice.
When running in the foreground with the --verbose, --debug, or --test options, Puppet agent logs directly to the terminal instead of to syslog.
When started with the --logdest <FILE> option, Puppet agent logs to the file specified by <FILE>.
Reporting for Puppet agent on *nix systems
In addition to local logging, Puppet agent submits a report to the Puppet master after each run. This can be disabled by setting report = false in puppet.conf.)