init.pp

file { 'create sasl_passwd':
        ensure  => present,
        owner   => root,
        group   => root,
        path    => '/etc/postfix/sasl_passwd',
        source  => 'puppet:///modules/postfix/sasl_passwd',
        require => Package['postfix'],
    } ->
    exec { 'postmap hash:/etc/postfix/sasl_passwd':

    } ->
    file { 'remove sasl_passwd':
        ensure  => absent,
        path    => '/etc/postfix/sasl_passwd',
    } ->
    exec { 'postconf -e \'smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt\'':

    }