Regenerate Puppet agent certificates

From time to time, you might encounter a situation in which you need to regenerate a certificate for an agent. Perhaps there is a security vulnerability in your infrastructure that you can remediate with a certificate regeneration, or maybe you're receiving SSL errors on your agent that are preventing you from performing normal operations.

As an alternative to performing these steps manually, on your master logged in as root, run puppet infrastructure run regenerate_agent_certificate agent=<AGENT_HOSTNAME> caserver=<CA_SERVER_HOSTNAME>. Your CA server is usually your master. You can specify this optional parameter: dns_alt_names – Comma-separated list of alternate DNS names to be added to the certificates generated for your agents. Important: To use the dns_alt_names parameter, you must configure Puppet Server with allow-subject-alt-names in the certificate-authority section of ca.conf. The puppet infrastructure run command leverages built-in Bolt plans to automate certain management tasks. To use this command, you must be able to connect using SSH from your master to any nodes that the command modifies. You can establish an SSH connection using key forwarding, a local key file, or by specifying keys in .ssh/config on your master. For more information, see Bolt OpenSSH configuration options.

Unless otherwise indicated, the following steps should be performed on your agent node.

1. On the master, clear the cert for the agent node. Run puppet cert clean <CERTNAME>.
2. On the agent, back up the /etc/puppetlabs/puppet/ssl/ directory.
   If something goes wrong, you may need to restore these directories so your deployment can stay functional. However, if you needed to regenerate your certs for security reasons and couldn't, you should contact Puppet support as soon as you restore service so we can help you secure your site.
3. Stop the Puppet agent, MCollective, and PXP agent services.

   puppet resource service puppet ensure=stopped
   puppet resource service mcollective ensure=stopped
   puppet resource service pxp-agent ensure=stopped

4. Delete the agent's SSL directory.
   • On *nix nodes, run rm -rf /etc/puppetlabs/puppet/ssl
   • On Windows nodes, delete the $confdir\ssl directory, using the Administrator confdir.
5. Remove the agent's cached catalog.
   • On *nix nodes, run rm -f /opt/puppetlabs/puppet/cache/client_data/catalog/<CERTNAME>.json
   • On Windows nodes, delete the $client_datadir\catalog\<CERTNAME>.json file, using the Administrator confdir.
6. Re-start the Puppet agent and MCollective services.

   puppet resource service puppet ensure=running
   puppet resource service mcollective ensure=running

   After the agent starts, it will automatically generate keys and request a new certificate from the CA Puppet master.
7. If you are not using autosigning, you will need to sign each agent node's certificate request. You can do this with the console's request manager, or by logging into the CA Puppet master server, running

   puppet cert list 
   puppet cert sign <NAME>

   After the agent node’s certificate is signed, you can either manually kick off a Puppet run from the console or command line, or wait for the agent to run based on the runinterval, the default of which is 30 minutes. At this point, the agent will perform a full catalog run, restart the PXP agent service, and will resume its role in your PE deployment.

   Tip: For information about autosigning, see Autosigning certificate requests.