documentation/docs/admin-guide/puppet/hiera.md

Hiera

Please refer to https://docs.puppet.com/hiera/ for a general Hiera introduction.

Our current hierarchy has seven levels (first will be considered first during value lookup):

• nodes (FQDN)
• subgroup (optional, puppet_subgroup attribute in sysdb)
• group (puppet_group attribute in sysdb)
• Hiera environments
• Puppet server specific
• global
• common

The first four layers can be edited by the admin in the respective Hiera Git repository. The common layer (default values) and the server specific layer (differences between test and prod) are part of the Puppet code repository. Finally the global layer contains a few configurations which are managed by the Core Linux Group outside of the normal Puppet release process, eg. for license management.

The values can be stored as classical YAML values or with encrypted yaml for secrets.

The filesystem structure is as follows (the last 3 cannot be controlled by a common admin):

1. %{::sysdb_env}/%{::group}/%{::fqdn}.yaml or %{::sysdb_env}/%{::group}/%{::subgroup}/%{::fqdn}.yaml
2. %{::sysdb_env}/%{::group}/%{::subgroup}.yaml
3. %{::sysdb_env}/%{::group}.yaml
4. %{::sysdb_env}/%{::sysdb_env}.yaml
5. %{::environment}/data/server_%{server_facts.servername}.yaml
6. /srv/puppet/data/global/global.yaml
7. %{::environment}/data/common.yaml

Depending if a subgroup is defined, the node specific YAML is at a different level in the filesysystem hierarchy.

The %{variable} notation is hiera specific.

Repositories

Hiera data are organized in different repositories. These repositories are located at: https://gitea.psi.ch/puppet

Each Hiera environment has a dedicated hiera repository, called data-<hiera_env>, eg. data-hpc. The first 4 levels of the filesystem structure shown before are actually the files inside this kind of repositories.

Any change to the repo will automatically trigger a redeployment of the new version of its content on the puppet master within a few seconds from the push.

Configuration

Secrets

To encrypt sensitive data in your hiera configuration you need the hiera-eyaml tool installed on your system.

To encrypt data you have to use the public key from your Hiera (data-*) git repository named eyaml_public_key.pem

For the lower hiera layers (global, server or data) it is on the Puppet server at /etc/puppetlabs/keys/eyaml/public_key.pkcs7.pem.

For to encrypt a simple string do

eyaml encrypt --pkcs7-public-key=eyaml_public_key.pem -s secret_string

and for a complete file

eyaml encrypt --pkcs7-public-key=eyaml_public_key.pem -f secret_file

and from pipe

eyaml encrypt --pkcs7-public-key=eyaml_public_key.pem --stdin

For example, to encrypt a password for a system you can do like this:

# openssl passwd -6 | eyaml encrypt --pkcs7-public-key=eyaml_public_key.pem --stdin
Password: 
Verifying - Password: 
string: ENC[PKCS7,MIIB2gYJKoZIhvcNAQcDoIIByzCCAccCAQ...sfLHuai6p+Mdukw/TT1BlKA==]

OR

block: >
  ENC[PKCS7,MIIB2gYJKoZIhvcNAQcDoIIByzCCAccCAQAxggEhMIIBHQIBAD
  AFMAACAQEwDQYJKoZIhvcNAQEBBQAEggEA1vyV8J3LYjfBz5zY1PIs9k9zIC
  ...
  c+MJa+CzicugI0Ptyq/anhhfWeDeBnZza1/9OCxWqqf3wEcnhJCmxYxBEOLR
  AxVw2cf3w0wGRuZ0373LHljGTsfLHuai6p+Mdukw/TT1BlKA==]
#

and place either the string or the block at the required place in your Hiera YAML.

Beside encrypting a complete e.g. content of a file, you can also encrypt only a single value. This can be done as follows:

letsencrypt::eab-kid: >
  ENC[PKCS7,MIIBmQYJKoZIhvcNAQcDoIIBijCCAYYCAQAxggEhMIIBHQIBAD
  ...

letsencrypt::eab-hmac-key: >
  ENC[PKCS7,MIIBygYJKoZIhvcNAQcDoIIBuzCCAbcCAQAxggEhMIIBHQIBAD
  ...

files::files:
  /etc/letsencrypt/cli.ini:
    mode: '0644'
    content: |
      server = https://one.digicert.com/mpki/api/v1/acme/v2/directory
      # Server authentication. Due to having this, we do not need to do a DNS challenge.
      eab-kid = %{lookup('lx-data::letsencrypt::eab-kid')}
      eab-hmac-key = %{lookup('lx-data::letsencrypt::eab-hmac-key')}

letsencrypt::eab-kid and letsencrypt::eab-hmac-key are arbitrary key names, you can use any key name you want, just ensure that they are unique.

Hiera Variable Interpolation

Within Hiera also variable interpolation might be use to include other Hiera keys or facts, etc. into the values. For details check out the Puppet documentation

As such an interpolation starts with %{, some key or file content (especially in Apache configuration) might be interpreted as variable interpolation and result in some part of the text disappear. Or it might simply the puppet run with Syntax error in string if Puppet fails to parse what it considers an interpolation. To escape a % you can write %{literal('%')} instead.