4.2. Initial SIMP Server Configuration

4.2.1. Using the SIMP Utility

In these instructions we will be using the config and bootstrap commands of the SIMP Utility, simp. The SIMP Utility provides a CLI intended to make the system initial configuration straightforward and repeatable.


For a list of the commands simp provides, type simp help. Type simp help <Command> for more information on a specific command.

4.2.2. Configuring the SIMP Server


Correct time across all systems is important to the proper functioning of SIMP and Puppet in general.

If a user has trouble connecting to the Puppet server and errors regarding certificate validation appear, check the Puppet server and client times to ensure they are synchronized.


Keep in mind as the installation process begins that Puppet does not work well with capital letters in host names. Therefore, they should not be used.

For the remainder of the document, we will assume that you use the ISO installation method and that you are logging in using a simp local user. Use the appropriate user for your environment if you installed via an alternate method.

  1. Log on as simp and run su - to gain root access.

  2. Type simp config and configure the system as prompted.

    • simp config will prompt you for system settings and then apply them as appropriate for bootstrapping the system.
    • When applicable, simp config will present you with a recommendation for each setting (variable). To keep a recommended value, press Enter. Otherwise, enter your desired value.
    • simp config generates a log file in /root/.simp containing details of the configuration selected and actions taken.
    • For more details about the installation variables set by simp config and the corresponding actions, see Advanced Configuration.
    • For a list of additional options, type simp help config.
      • simp config --dry-run will run through all of the simp config prompts without applying any changes to the system. This is the option to run to become familiar with the variables set by simp config or generate a configuration file to be used as a template for subsequent simp config runs.
      • simp config -a <Config File> will load a previously generated configuration (aka the ‘answers’ file) in lieu of prompting for settings, and then apply the settings. This is the option to run for systems that will be rebuilt often. Please note, however, if you edit the answers file, only configuration settings for which you would be prompted by simp config can be modified in that file. Any changes made to settings that simp config automatically determines will be ignored.


    Once simp config has been run, three SIMP configuration files will be generated:

    1. /root/.simp/simp_conf.yaml: File containing all your simp config settings; can include additional settings related to ones you entered and other settings required for SIMP.
    2. /etc/puppetlabs/code/environments/simp/hieradata/simp_config_settings.yaml: File containing global Hiera data relevant to SIMP clients and the SIMP server.
    3. /etc/puppetlabs/code/environments/simp/hieradata/hosts/<server_fqdn>.yaml: SIMP server host specific Hiera configuration.
  3. Type simp bootstrap


    If progress bars are of equal length and the bootstrap finishes quickly, a problem has occurred. This is most likely due to an error in SIMP configuration. Refer to the previous step and make sure that all configuration options are correct.

    If this happens, you can debug by either looking at the log files or by running puppet agent -t --masterport=8150.

  4. Type reboot to reboot and apply the necessary kernel configuration items.

4.2.3. Optional: Extract the full OS Package Set

The SIMP ISO attempts to contain everything that you need to run a base system. However, if you did not install via ISO, or you require additional stock packages, you can use the following procedure to extract the vendor ISOs.

  1. Log on as simp and run su - to gain root access.

  2. Run puppet for the first time.

    Type: puppet agent -t

  3. Copy the appropriate vendor OS ISO(s) to the server and unpack using the unpack_dvd utility. This creates a new tree under /var/www/yum/<OperatingSystem> suitable for serving to clients.

    Type: unpack_dvd CentOS-RHEL_MAJOR_VERSION-x86_64-DVD-####.iso

  4. Update your system using yum. The updates applied will depend on what ISO you initially used.

    Type: yum clean all; yum makecache

4.2.4. Advanced Configuration

The goal of simp config is to allow the user to quickly configure the SIMP server with minimal user input/operations. To that end simp config sets installation variables based on information gathered from the user, existing system settings, and SIMP security requirements. It then applies the smallest subset of these system settings that is required to bootstrap the system with Puppet. Both the installation variables and their application via simp config are described in subsections that follow. Installation Variables

This section describes the installation variables set by simp config. Although the table that follows lists all possible installation variables, the user will not be prompted for all of them, nor will all of them appear in the configuration files generated by simp config. Some of these variables will be automatically set based on other installation variables, system settings, or SIMP security requirements. Others will be omitted because either they are unnecessary for a particular site configuration, or their defaults are appropriate. Also, please note that variables beginning with ‘cli::’ are only used internally by simp config, itself. The ‘cli::’ variables are written to simp_conf.yaml, but not persisted to any Puppet hieradata files.


  • Not all the settings listed below can be preset in a configuration file input to simp config, via either -a <Config File> or -A <Config File>. Only settings for which you would be prompted, if you ran simp config interactively, can be preset. All other settings will be automatically determined by simp config, disregarding your input.
  • simp config behaves differently (asks different questions, automatically determines different settings) depending on the SIMP installation type. This is because it can safely assume certain server setup has been done, only if SIMP has been installed from the SIMP-provided ISO. For example, consider a simp local user. When SIMP is installed from ISO, simp config can safely assume that this user is the backup user installed by the ISO to prevent server lockout. As such, su and ssh privileges for the simp user should be allowed. For non-ISO installs, however, it would not be prudent for simp config to grant just any simp user both su and ssh privileges.
  • simp config detects that SIMP has been installed from a SIMP-provided ISO by the presence of /etc/yum.repos.d/simp_filesystem.repo.
Variable Description
cli::is_ldap_server Whether the SIMP server will also be the LDAP server.
cli::network::dhcp Whether to use DHCP for the network; dhcp to enable DHCP, static otherwise
cli::network::gateway Default gateway
cli::network::hostname FQDN of server
cli::network::interface Network interface to use
cli::network::ipaddress IP address of server
cli::network::netmask Netmask of the system
cli::network::set_up_nic Whether to set up the network interface; true or false
cli::set_grub_password Whether to set a GRUB password on the server; true or false
cli::set_production_to_simp Whether to set default Puppet environment to ‘simp’; true or false
cli::simp::scenario SIMP scenario; simp = full SIMP system, simp_lite = SIMP system with some security features disabled for clients, poss = SIMP system with all security features disabled for clients.
cli::use_internet_simp_yum_repos Whether to configure SIMP nodes to use internet SIMP and SIMP dependency YUM repositories.
grub::password GRUB password hash
puppetdb::master::config::puppetdb_port Port used by the puppet database
puppetdb::master::config::puppetdb_server DNS name or IP of puppet database server
simp_openldap::server::conf::rootpw LDAP Root password hash
simp_options::dns::search Search domain for DNS
simp_options::dns::servers List of DNS servers for the managed hosts
simp_options::fips Enable FIPS-140-2 compliance; true or false; value automatically set to detected system FIPS status
simp_options::ldap Whether to use LDAP; true or false
simp_options::ldap::base_dn LDAP Server Base Distinguished Name
simp_options::ldap::bind_dn LDAP Bind Distinguished Name
simp_options::ldap::bind_hash LDAP Bind password hash
simp_options::ldap::bind_pw LDAP Bind password
simp_options::ldap::master LDAP master URI
simp_options::ldap::sync_dn LDAP Sync Distinguished Name
simp_options::ldap::sync_hash LDAP Sync password hash
simp_options::ldap::sync_pw LDAP Sync password
simp_options::ldap::uri List of LDAP server URIs
simp_options::ntpd::servers NTP servers
simp_options::puppet::ca FQDN of Puppet Certificate Authority (CA)
simp_options::puppet::ca_port Port Puppet CA will listen on
simp_options::puppet::server FQDN of the puppet server
simp_options::sssd Whether to use SSSD
simp_options::syslog::failover_log_servers IP addresses of failover log servers
simp_options::syslog::log_servers IP addresses of primary log servers
simp_options::trusted_nets Subnet used for clients managed by the puppet server
simp::runlevel Default system run level; 1-5
simp::server::allow_simp_user Whether to allow local ‘simp’ user su and ssh privileges.
simp::yum::repo::local_os_updates::enable_repo Whether to enable the SIMP-managed, OS Update YUM repository that the SIMP ISO installs on the SIMP server.
simp::yum::repo::local_os_updates::servers YUM server(s) for SIMP-managed, OS Update packages
simp::yum::repo::local_simp::enable_repo Whether to enable the SIMP-managed, SIMP and SIMP dependency YUM repository that the SIMP ISO installs on the SIMP server.
simp::yum::repo::local_simp::servers YUM server(s) for SIMP-managed, SIMP and SIMP dependency packages
sssd::domains List of SSSD domains
svckill::mode Strategy svckill should use when it encounters undeclared services; enforcing = shutdown and disable all services not listed in your manifests or the exclusion file warning = only report what undeclared services should be shut down and disabled, without actually making the changes to the system
useradd::securetty A list of TTYs for which the root user can login simp config Actions

In addition to creating the three configuration, YAML files, simp config performs a limited set of actions in order to prepare the system for bootstrapping. Although the table that follows lists all possible simp config actions, not all of these actions will apply for all site configurations.

Category Actions Performed
Certificates If no certificates for the host are found in /var/simp/environments/simp/site_files/pki_files/ files/keydist, simp config will use SIMP’s FakeCA to generate interim host certificates. These certificates, which are independent of the certificates managed by Puppet, are required by SIMP and should be replaced by certificates from an official Certificate Authority, as soon as is practical.
Digest Algorithm for FIPS When the system is in FIPS mode, simp config will set the Puppet digest algorithm to sha256 to prevent any Puppet-related actions executed by simp config from using MD5 checksums. Note that this is not all that must be done to enable FIPS. The complete set of actions required to support FIPS is handled by simp bootstrap.
GRUB When the user selects to set the GRUB password simp config will set the password in the appropriate grub configuration file, /etc/grub.conf or /etc/grub2.cfg.

When the SIMP server is also an LDAP server, simp config

  • Adds simp::server::ldap to the SIMP server host YAML file, which allows the SIMP server to act as a LDAP server
  • Adds the hash of the user-supplied LDAP root password to the SIMP server host YAML file as simp_openldap::server::conf::rootpw to the SIMP
Lockout Prevention

When the SIMP server is installed from ISO, the install creates a local simp user that the SIMP server configures to have both su and ssh privileges. (This user is provided to prevent server lockout, as, per security policy, SIMP by default disables logins via ssh for all users, including ‘root’.) So, when SIMP is not installed from ISO, simp config does the following:

  • Warns the operator of this problem
  • Writes a lock file containing details on how to rectify the problem. This lock file prevents simp bootstrap from running until the user manually fixes the problem.
  • Turns off the SIMP server configuration that allows su and ssh privileges for an inapplicable simp user.
  • When the user selects to configure the network interface, simp config uses Puppet to set the network interface parameters in system networking files and to bring up the interface.
  • simp config sets the hostname.
  • Copies SIMP modules installed via RPM in /usr/share/simp into the Puppet environments directory /etc/puppetlabs/code/environments if necessary.
  • When selected, sets the default Puppet environment to ‘simp’, backing up the existing ‘production’ environment, if it exists.
  • Creates/updates /etc/puppetlabs/puppet/autosign.conf.
  • Updates the following Puppet settings: digest_algorithm, keylength, server, ca_server, ca_port, and trusted_server_facts.
  • Updates /etc/hosts to ensure a puppet server entry exists.
SIMP Hiera & Site Manifest
  • Sets the $simp_scenario variable in the site.pp of the ‘simp’ environment to the user-selected scenario.
  • If a host YAML file for the SIMP server does not already exist in /etc/puppetlabs/code/environments/simp/hieradata/hosts does not already exist, simp config will create one from a SIMP template.
  • Updates the SIMP server host YAML file with appropriate PuppetDB settings.
  • Creates YAML file containing global hieradata relevant to both the SIMP server and SIMP clients in the ‘simp’, environment, simp/hieradata/simp_config_settings.yaml
  • When the SIMP filesystem YUM repo from an ISO install exists (/etc/yum.repos.d/simp_filesystem.repo), simp config
    • Configures SIMP server to act as a YUM server for the on-server repo, by adding the simp::server::yum class to the SIMP server host YAML file.
    • Configures SIMP clients to use the SIMP server’s YUM repos by adding simp::yum::repo::local_os_updates and simp::yum::repo::local_simp classes to simp_config_settings.yaml.
    • Disables the use of the simp::yum::repo::local* repos in the SIMP server’s host YAML file, as it is already configured to use the more efficient, filesystem repo.
    • Updates the appropriate OS YUM Updates repository, contained at /var/www/yum/OSTYPE/MAJORRELEASE/ARCH.
    • Disables any default CentOS repos.
  • When the SIMP filesystem YUM repo does not exist, but the user wants to use internet repos simp config
    • Enables internet SIMP server repos in the SIMP server host YAML file by adding the simp::yum::repo::internet_simp_server class.
    • Enables internet SIMP dependency repos for both SIMP clients and in the SIMP server by adding the simp::yum::repo::internet_simp_dependencies class to simp_config_settings.yaml.
  • When the SIMP filesystem YUM repo does not exist and the user does not want to use internet repos, simp config
    • Checks the configuration of the SIMP server’s YUM repos via repoquery. If this check fails, writes a lock to prevent simp bootstrap from running until the user manually fixes the issue.
    • Reminds the user to (manually) set up YUM repos for SIMP clients.