Examples of using custom facts in Puppet

1. Custom Facts
Jere Julian
2016 Raleigh Puppet User Group

2. Facter

3. Built-in Facts
$ puppet facts
{
"facterversion": "3.2.0",
"interfaces":
"cpu,et1,et2,et3,et4,fabric,lo,ma1,vmnicet1,vmnicet2,vmnicet3
,vmnicet4",
"os": {
"architecture": "x86_64",
"family": "Linux",
"hardware": "x86_64",
"name": "AristaEOS",
"release": {
"full": "4.14.9",
"major": "4",
"minor": "14"
},
"selinux": {
"enabled": false
}
},
"osfamily": "Linux",
"is_virtual": true,
"kernel": "Linux",
"kernelmajversion": "3.4",
"kernelrelease": "3.4.43.Ar-2758566.41491M",
"kernelversion": "3.4.43.Ar",
"networking": {
"domain": "example.com",
"fqdn": "jere-debug-agent1.example.com",
"hostname": "jere-debug-agent1",
"interfaces": {
"cpu": {
"mac": "8e:0c:d0:a2:92:73",
"mtu": 1500
},
"et1": {
"mac": "00:50:56:1e:b2:64",
"mtu": 9214
},
}
},
"name": "jere-debug-agent1.example.com",
"values": {
"aio_agent_version": "1.5.2",
"architecture": "x86_64",
"augeas": {
"version": "1.4.0"
},
"augeasversion": "1.4.0",

4. External facts
• Embedded in hostname: dc01-r3-prod-web04
• Facts files: /etc/puppetlabs/facter/facts.d/ or
<module>/facts.d/
– Files may be txt, json, yaml, or scripts
– Dir must be created
facts.txt:
datacenter=portland
application=doc
team=TSE

5. Custom facts
• <module>/lib/facter/<name>.rb
• Parse the hostname into facts
Facter.add(:datacenter) do
setcode do
# Ex: dc01-r3-prod-web04
Facter.value(:hostname)[0..3]
end
end

6. Custom facts - Confinement
Facter.add('lldp_neighbors') do
confine :operatingsystem => "AristaEOS"
setcode do
require 'rbeapi/client'
node = Rbeapi::Client.connect_to('localhost')
neighbors = node.enable('show lldp neighbors')
if neighbors[0][:encoding] == "json”
newhash = Hash.new { |hash, key| hash[key] = [] }
neighbors[0][:result]["lldpNeighbors"].each { |n| newhash[n["port"]]<<n }
newhash
end
end
end

7. Custom facts – structured or string
"lldp_neighbors": {
"Management1": [
{
"ttl": 120,
"neighborDevice": "jere-debug-agent2.example.com",
"neighborPort": "Management1",
"port": "Management1"
},
{
"ttl": 120,
"neighborDevice": "eosplus-demo-puppet2",
"neighborPort": "0050.569b.ad8d",
"port": "Management1"
}
]
},

8. Custom facts - precedence
Facter.add(:rubypath) do
has_weight 100
setcode 'which ruby'
end
Facter.add(:rubypath) do
has_weight 50
setcode do
’I dont know!’
end
end

9. Aggregates
• Structured facts can be aggregated chuncks
• :type => :aggregate
chunk(:one) do
'Chunk one returns this. '
end
chunk(:two) do
'Chunk two returns this.'
end
OR
aggregate do |chunks|
…
end

10. References
• https://puppet.com/blog/hiera-hierarchies-
and-custom-facts-everyone-needs
• https://docs.puppet.com/facter/3.4/fact_over
view.html
• https://docs.puppet.com/facter/3.4/custom_f
acts.html