Managing Zones¶
In the Domain Name System, zones are used to break up the namespace into more
easily managed pieces. For example, within the root zone . there are zones
for each of the top level domains such as .org. and .com. and
responsiblity for each of those zones could lie with a different organisation.
Within those zones, there are then delegations to other zones, such as
example.org. or example.com. which might again be managed by a
different organisation and/or set of nameservers. This forms a hierarchy of
responsibility, with the higher levels being mainly composed of delegations to
lower levels.
Zones in Designate¶
Zones in Designate model the ownership concept from DNS itself, where any given zone can only be owned by a single tenant. However, while DNS is able to support a hierarchy of zones, there is no support for delegating subzones to another tenant, and one tenant cannot create zones that lie within the zone of another tenant.
The creation of a zone in Designate also creates two recordsets automatically: an SOA record and an NS record. By default these records cannot be modified without the admin role.
Zones vs Top Level Domains¶
While top level domains are considered zones from a DNS perspective, in Designate they are often not managed as a zone, and instead have their own TLD type that allows any tenant to create zones within that TLD and restricts tenants from creating zones that aren’t within a managed TLD. If no TLDs are being managed within Designate, tenants can create any zone aside from the root zone and top level domains.
Creating a zone¶
Creating a zone requires only the name of the zone and an email address of the party responsible for the zone.
$ openstack zone create --email dnsmaster@example.com example.com. +----------------+--------------------------------------+ | Field | Value | +----------------+--------------------------------------+ | action | CREATE | | attributes | {} | | created_at | 2016-07-13T14:54:16.000000 | | description | None | | email | dnsmaster@example.com | | id | 14093115-0f0f-497a-ac69-42235e46c26f | | masters | | | name | example.com. | | pool_id | 794ccc2c-d751-44fe-b57f-8894c9f5c842 | | project_id | 656bc359067844fba6005d400f19df76 | | serial | 1468421656 | | status | PENDING | | transferred_at | None | | ttl | 3600 | | type | PRIMARY | | updated_at | None | | version | 1 | +----------------+--------------------------------------+
Note that the state is PENDING. Designate has received the request to create the zone, but may not have completed it yet. After a short time, verify successful creation of the DNS Zone:
$ openstack zone list +--------------------------------------+--------------+---------+------------+--------+--------+ | id | name | type | serial | status | action | +--------------------------------------+--------------+---------+------------+--------+--------+ | 14093115-0f0f-497a-ac69-42235e46c26f | example.com. | PRIMARY | 1468421656 | ACTIVE | NONE | +--------------------------------------+--------------+---------+------------+--------+--------+
There will now be two recordsets visible in the zone:
$ openstack recordset list example.com. +--------------------------------------+--------------+------+---------------------------------------------------------------------+--------+--------+ | id | name | type | records | status | action | +--------------------------------------+--------------+------+---------------------------------------------------------------------+--------+--------+ | 269cf8d2-c498-49a8-aef9-01e81d078313 | example.com. | SOA | ns1.devstack.org. admin.example.com. 1618291836 3509 600 86400 3600 | ACTIVE | NONE | | 31b50023-88b2-4011-b31b-474fa25a8e39 | example.com. | NS | ns1.devstack.org. | ACTIVE | NONE | +--------------------------------------+--------------+------+---------------------------------------------------------------------+--------+--------+
The values for refresh, retry, minimum and expire on the SOA record are set by the Designate operator. The TTL, however, can be modified by users via the zone:
$ openstack zone set example.com. --ttl 3000 +----------------+--------------------------------------+ | Field | Value | +----------------+--------------------------------------+ | action | UPDATE | | attributes | | | created_at | 2021-04-13T05:30:36.000000 | | description | None | | email | admin@example.com | | id | b9861a55-0e50-4896-8ab9-25d8c4494f64 | | masters | | | name | example.com. | | pool_id | 794ccc2c-d751-44fe-b57f-8894c9f5c842 | | project_id | 9d69e3a004aa40c581f00d7bb7763e0a | | serial | 1618545015 | | status | PENDING | | transferred_at | None | | ttl | 3000 | | type | PRIMARY | | updated_at | 2021-04-16T03:50:15.000000 | | version | 11 | +----------------+--------------------------------------+
The dig tool can be used to query one of the backend nameservers to confirm
the result. In this example, there is a DNS server at 192.168.122.186
managed by designate as part of the default pool.
$ dig @192.168.122.186 example.com. ; <<>> DiG 9.11.20-RedHat-9.11.20-5.el8_3.1 <<>> @192.168.122.186 example.com. ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63663 ;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ; COOKIE: 970f584e4cb93505eaf46f526079097ac959da76062f1d0a (good) ;; QUESTION SECTION: ;example.com. IN A ;; AUTHORITY SECTION: example.com. 3000 IN SOA ns1.devstack.org. admin.example.com. 1618545015 3509 600 86400 3600 ;; Query time: 0 msec ;; SERVER: 192.168.122.186#53(192.168.122.186) ;; WHEN: Fri Apr 16 03:50:18 UTC 2021 ;; MSG SIZE rcvd: 126
In the AUTHORITY section, the numeric value between the name and IN is
the TTL, which has updated to the new value of 3000.
Deleting a zone¶
A zone can be deleted using either its name or ID:
$ openstack zone delete example.com. +----------------+--------------------------------------+ | Field | Value | +----------------+--------------------------------------+ | action | DELETE | | attributes | | | created_at | 2021-04-13T05:30:36.000000 | | description | None | | email | admin@example.com | | id | b9861a55-0e50-4896-8ab9-25d8c4494f64 | | masters | | | name | example.com. | | pool_id | 794ccc2c-d751-44fe-b57f-8894c9f5c842 | | project_id | 9d69e3a004aa40c581f00d7bb7763e0a | | serial | 1618545024 | | status | PENDING | | transferred_at | None | | ttl | 3000 | | type | PRIMARY | | updated_at | 2021-04-16T10:18:05.000000 | | version | 15 | +----------------+--------------------------------------+
Any records present in the zone are also deleted and will no longer resolve.
