in ssh_users/libraries/user.rb [92:104]
def next_free_uid(starting_from = 4000)
candidate = starting_from
existing_uids = @@allocated_uids
(node[:passwd] || node[:etc][:passwd]).each do |username, entry|
existing_uids << entry[:uid] unless existing_uids.include?(entry[:uid])
end
while existing_uids.include?(candidate) do
candidate += 1
end
@@allocated_uids << candidate
candidate
end