Module: Bosh::Director::DnsHelper

Included in:
Api::Controllers::BaseController, Config, Bosh::Director::DeploymentPlan::DeploymentSpecParser, Bosh::Director::DeploymentPlan::DnsBinder, Bosh::Director::DeploymentPlan::DynamicNetwork, Bosh::Director::DeploymentPlan::Instance, Bosh::Director::DeploymentPlan::JobSpecParser, Bosh::Director::DeploymentPlan::ManualNetwork, Bosh::Director::DeploymentPlan::Network, Bosh::Director::DeploymentPlan::NetworkSubnet, Bosh::Director::DeploymentPlan::Planner, InstanceDeleter, InstanceUpdater, Jobs::DeleteDeployment
Defined in:
lib/bosh/director/dns_helper.rb

Constant Summary collapse

SOA =

primary_ns contact serial refresh retry expire minimum

"localhost hostmaster@localhost 0 10800 604800 30"
TTL_5M = 
300
TTL_4H = 
3600 * 4

Instance Method Summary collapse

Instance Method Details

#add_default_dns_server(servers) ⇒ Object

add default dns server to an array of dns servers



63
64
65
66
67
68
69
70
71
72
73
 
# File 'lib/bosh/director/dns_helper.rb', line 63

def add_default_dns_server(servers)
  return servers unless Config.dns_enabled?

  default_server = default_dns_server
  if default_server && default_server != "127.0.0.1"
    (servers ||= []) << default_server
    servers.uniq!
  end

  servers
end

#canonical(string) ⇒ Object 



21
22
23
24
25
26
27
28
29
30
31
32
33
 
# File 'lib/bosh/director/dns_helper.rb', line 21

def canonical(string)
  # a-z, 0-9, -, case insensitive, and must start with a letter
  string = string.downcase.gsub(/_/, "-").gsub(/[^a-z0-9-]/, "")
  if string =~ /^(\d|-)/
    raise DnsInvalidCanonicalName,
          "Invalid DNS canonical name `#{string}', must begin with a letter"
  end
  if string =~ /-$/
    raise DnsInvalidCanonicalName,
          "Invalid DNS canonical name `#{string}', can't end with a hyphen"
  end
  string
end

#default_dns_server ⇒ Object

returns the default DNS server



58
59
60
 
# File 'lib/bosh/director/dns_helper.rb', line 58

def default_dns_server
  Config.dns["server"] if Config.dns
end

#delete_dns_records(record_pattern, domain_id = nil) ⇒ Object

deletes all DNS records matching the pattern

Parameters:

  • record_pattern (String) —

    SQL pattern

  • domain_id (Integer) (defaults to: nil) —

    domain record id



143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
 
# File 'lib/bosh/director/dns_helper.rb', line 143

def delete_dns_records(record_pattern, domain_id=nil)
  records = Models::Dns::Record.filter(:name.like(record_pattern))
  if domain_id
    records = records.filter(:domain_id => domain_id)
  end

  # delete A records and collect all IPs for later
  ips = []
  records.each do |record|
    ips << record.content
    @logger.info("Deleting DNS record: #{record.name}")
    record.destroy
  end

  # delete PTR records from IP list
  ips.each do |ip|
    records = Models::Dns::Record.filter(:name.like(reverse_host(ip)))
    records.each do |record|
      @logger.info("Deleting reverse DNS record: #{record.name}")
      record.destroy
    end
  end

  # see if any of the reverse domains are empty and should be deleted
  ips.each do |ip|
    reverse = reverse_domain(ip)
    rdomain = Models::Dns::Domain.filter(:name => reverse,
                                         :type => "NATIVE")
    rdomain.each do |domain|
      delete_empty_domain(domain)
    end
  end
end

#delete_empty_domain(domain) ⇒ Object 



177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
 
# File 'lib/bosh/director/dns_helper.rb', line 177

def delete_empty_domain(domain)
  # If the count is 2, it means we only have the NS & SOA record
  # and the domain is "empty" and can be deleted
  if domain.records.size == 2
    @logger.info("Deleting empty reverse domain #{domain.name}")

    # Since DNS domain can be deleted by multiple threads
    # it's possible for database to return 0 rows modified result.
    # In this specific case that's a valid return value
    # but Sequel usually considers that an error.
    # ('Attempt to delete object did not result in a single row modification')
    domain.require_modification = false

    # Cascaded - all records are removed
    domain.destroy
  end
end

#dns_domain_name ⇒ Object

returns the DNS domain name



76
77
78
 
# File 'lib/bosh/director/dns_helper.rb', line 76

def dns_domain_name
  Config.dns_domain_name
end

#dns_ns_record ⇒ Object

returns the DNS name server record



81
82
83
 
# File 'lib/bosh/director/dns_helper.rb', line 81

def dns_ns_record
  "ns.#{dns_domain_name}"
end

#dns_servers(network, spec, add_default_dns = true) ⇒ Object

build a list of dns servers to use



36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
 
# File 'lib/bosh/director/dns_helper.rb', line 36

def dns_servers(network, spec, add_default_dns = true)
  servers = nil
  dns_property = safe_property(spec, "dns",
                               :class => Array, :optional => true)
  if dns_property
    servers = []
    dns_property.each do |dns|
      dns = NetAddr::CIDR.create(dns)
      unless dns.size == 1
        invalid_dns(network, "must be a single IP")
      end

      servers << dns.ip
    end
  end

  return servers unless add_default_dns

  add_default_dns_server(servers)
end

#flush_dns_cache ⇒ Object

Purge cached DNS records



204
205
206
207
208
209
210
211
212
213
214
 
# File 'lib/bosh/director/dns_helper.rb', line 204

def flush_dns_cache
  flush_command = Config.dns['flush_command']
  if flush_command && !flush_command.empty?
    stdout, stderr, status = Open3.capture3(flush_command)
    if status == 0
      @logger.debug("Flushed #{stdout.chomp} records from DNS cache")
    else
      @logger.warn("Failed to flush DNS cache: #{stderr.chomp}")
    end
  end
end

#invalid_dns(network, reason) ⇒ Object

Parameters:

  • network (String) —

    name

  • reason (String)

Raises:

  • NetworkInvalidDns



198
199
200
201
 
# File 'lib/bosh/director/dns_helper.rb', line 198

def invalid_dns(network, reason)
  raise NetworkInvalidDns,
        "Invalid DNS for network `#{network}': #{reason}"
end

#reverse_domain(ip) ⇒ String

Returns reverse dns domain name for an IP.

Parameters:

  • ip (String) —

    IP address

Returns:

  • (String) —

    reverse dns domain name for an IP



11
12
13
 
# File 'lib/bosh/director/dns_helper.rb', line 11

def reverse_domain(ip)
  reverse(ip, 2)
end

#reverse_host(ip) ⇒ String

Returns reverse dns name for an IP used for a PTR record.

Parameters:

  • ip (String) —

    IP address

Returns:

  • (String) —

    reverse dns name for an IP used for a PTR record



17
18
19
 
# File 'lib/bosh/director/dns_helper.rb', line 17

def reverse_host(ip)
  reverse(ip, 3)
end

#update_dns_a_record(domain, name, ip_address) ⇒ Object

create/update DNS A record



86
87
88
89
90
91
92
93
94
95
96
97
 
# File 'lib/bosh/director/dns_helper.rb', line 86

def update_dns_a_record(domain, name, ip_address)
  record = Models::Dns::Record.find(:domain_id => domain.id,
                                    :name => name)
  if record.nil?
    record = Models::Dns::Record.new(:domain_id => domain.id,
                                     :name => name, :type => "A",
                                     :ttl => TTL_5M)
  end
  record.content = ip_address
  record.change_date = Time.now.to_i
  record.save
end

#update_dns_ptr_record(name, ip_address) ⇒ Object

create/update DNS PTR records (for reverse lookups)



100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
 
# File 'lib/bosh/director/dns_helper.rb', line 100

def update_dns_ptr_record(name, ip_address)
  reverse_domain = reverse_domain(ip_address)
  reverse_host = reverse_host(ip_address)

  rdomain = Models::Dns::Domain.safe_find_or_create(:name => reverse_domain,
                                                    :type => "NATIVE")
  Models::Dns::Record.find_or_create(:domain_id => rdomain.id,
                                     :name => reverse_domain,
                                     :type =>'SOA', :content => SOA,
                                     :ttl => TTL_4H)

  Models::Dns::Record.find_or_create(:domain_id => rdomain.id,
                                     :name => reverse_domain,
                                     :type =>'NS', :ttl => TTL_4H,
                                     :content => dns_ns_record)

  record = Models::Dns::Record.find(:content => name, :type =>'PTR')

  # delete the record if the IP address changed
  if record && record.name != reverse_host
    id = record.domain_id
    record.destroy
    record = nil

    # delete the domain if the domain id changed and it's empty
    if id != rdomain.id
      delete_empty_domain(Models::Dns::Domain[id])
    end
  end

  unless record
    record = Models::Dns::Record.new(:domain_id => rdomain.id,
                                     :name => reverse_host,
                                     :type =>'PTR', :ttl => TTL_5M)
  end
  record.content = name
  record.change_date = Time.now.to_i
  record.save
end