用OpenStack Designate构建一个DNS即服务（DNSaaS）

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学习如何安装和配置 Designate，这是一个 OpenStack 的多租户 DNS 即服务（DNSaaS）。

Designate 是一个多租户的 DNS 即服务，它包括一个用于域名和记录管理的 REST API 和集成了 Neutron 的框架，并支持 Bind9。

DNSaaS 可以提供：

• 一个管理区域和记录的干净利落的 REST API
• 自动生成记录（集成 OpenStack）
• 支持多个授权名字服务器
• 可以托管多个项目/组织

Designate's architecture

这篇文章解释了如何在 CentOS 和 RHEL 上手动安装和配置 Designate 的当前版本，但是同样的配置也可以用在其它发行版上。

在 OpenStack 上安装 Designate

在我的 GitHub 仓库里，我已经放了 Ansible 的 bind 和 Designate 角色的示范设置。

这个设置假定 bing 服务是安装 OpenStack 控制器节点之外（即使你可以在本地安装 bind）。

1、在 OpenStack 控制节点上安装 Designate 和 bind 软件包：

# yum install openstack-designate-* bind bind-utils -y

2、创建 Designate 数据库和用户：

MariaDB [(none)]> CREATE DATABASE designate CHARACTER SET utf8 COLLATE utf8_general_ci;
       
MariaDB [(none)]> GRANT ALL PRIVILEGES ON designate.* TO \
'designate'@'localhost' IDENTIFIED BY 'rhlab123';
 
MariaDB [(none)]> GRANT ALL PRIVILEGES ON designate.* TO 'designate'@'%' \
IDENTIFIED BY 'rhlab123';

注意：bind 包必须安装在控制节点之外才能使远程名字服务控制Remote Name Daemon Control（RNDC）功能正常。

配置 bind（DNS 服务器）

1、生成 RNDC 文件：

rndc-confgen -a -k designate -c /etc/rndc.key -r /dev/urandom
 
cat <<EOF> etcrndc.conf
include "/etc/rndc.key";
options {
  default-key "designate";
  default-server {{ DNS_SERVER_IP }};
  default-port 953;
};
EOF

2、将下列配置添加到 named.conf：

include "/etc/rndc.key"; 
controls {
  inet {{ DNS_SERVER_IP }} allow { localhost;{{ CONTROLLER_SERVER_IP }}; } keys { "designate"; };
};

在 option 节中，添加：

options {
  ...
  allow-new-zones yes;
  request-ixfr no;
  listen-on port 53 { any; };
  recursion no;
  allow-query { 127.0.0.1; {{ CONTROLLER_SERVER_IP }}; };
};

添加正确的权限：

chown named:named /etc/rndc.key
chown named:named /etc/rndc.conf
chmod 600 /etc/rndc.key
chown -v root:named /etc/named.conf
chmod g+w /var/named
 
# systemctl restart named
# setsebool named_write_master_zones 1

3、把 rndc.key 和 rndc.conf 推入 OpenStack 控制节点：

# scp -r /etc/rndc* {{ CONTROLLER_SERVER_IP }}:/etc/

创建 OpenStack Designate 服务和端点

输入：

# openstack user create --domain default --password-prompt designate
# openstack role add --project services --user designate admin
# openstack service create --name designate --description "DNS" dns
 
# openstack endpoint create --region RegionOne dns public http://{{ CONTROLLER_SERVER_IP }}:9001/
# openstack endpoint create --region RegionOne dns internal http://{{ CONTROLLER_SERVER_IP }}:9001/  
# openstack endpoint create --region RegionOne dns admin http://{{ CONTROLLER_SERVER_IP }}:9001/

配置 Designate 服务

1、编辑 /etc/designate/designate.conf：

在 [service:api] 节配置 auth_strategy：

[service:api]
listen = 0.0.0.0:9001
auth_strategy = keystone
api_base_uri = http://{{ CONTROLLER_SERVER_IP }}:9001/
enable_api_v2 = True
enabled_extensions_v2 = quotas, reports

在 [keystone_authtoken] 节配置下列选项：

[keystone_authtoken]
auth_type = password
username = designate
password = rhlab123
project_name = service
project_domain_name = Default
user_domain_name = Default
www_authenticate_uri = http://{{ CONTROLLER_SERVER_IP }}:5000/
auth_url = http://{{ CONTROLLER_SERVER_IP }}:5000/ 

在 [service:worker] 节，启用 worker 模型：

enabled = True
notify = True

在 [storage:sqlalchemy] 节，配置数据库访问：

[storage:sqlalchemy]
connection = mysql+pymysql://designate:rhlab123@{{ CONTROLLER_SERVER_IP }}/designate

填充 Designate 数据库：

# su -s /bin/sh -c "designate-manage database sync" designate

2、 创建 Designate 的 pools.yaml 文件（包含 target 和 bind 细节）：

编辑 /etc/designate/pools.yaml：

- name: default
  # The name is immutable. There will be no option to change the name after
  # creation and the only way will to change it will be to delete it
  # (and all zones associated with it) and recreate it.
  description: Default Pool
 
  attributes: {}
 
  # List out the NS records for zones hosted within this pool
  # This should be a record that is created outside of designate, that
  # points to the public IP of the controller node.
  ns_records:
    - hostname: {{Controller_FQDN}}. # Thisis mDNS
      priority: 1
 
  # List out the nameservers for this pool. These are the actual BIND servers.
  # We use these to verify changes have propagated to all nameservers.
  nameservers:
    - host: {{ DNS_SERVER_IP }}
      port: 53
 
  # List out the targets for this pool. For BIND there will be one
  # entry for each BIND server, as we have to run rndc command on each server
  targets:
    - type: bind9
      description: BIND9 Server 1
 
      # List out the designate-mdns servers from which BIND servers should
      # request zone transfers (AXFRs) from.
      # This should be the IP of the controller node.
      # If you have multiple controllers you can add multiple masters
      # by running designate-mdns on them, and adding them here.
      masters:
        - host: {{ CONTROLLER_SERVER_IP }}
          port: 5354
 
      # BIND Configuration options
      options:
        host: {{ DNS_SERVER_IP }}
        port: 53
        rndc_host: {{ DNS_SERVER_IP }}
        rndc_port: 953
        rndc_key_file: /etc/rndc.key
        rndc_config_file: /etc/rndc.conf

填充 Designate 池：

su -s /bin/sh -c "designate-manage pool update" designate

3、启动 Designate 中心和 API 服务：

systemctl enable --now designate-central designate-api

4、验证 Designate 服务运行：

# openstack dns service list
 
+--------------+--------+-------+--------------+
| service_name | status | stats | capabilities |
+--------------+--------+-------+--------------+
| central      | UP     | -     | -            |
| api          | UP     | -     | -            |
| mdns         | UP     | -     | -            |
| worker       | UP     | -     | -            |
| producer     | UP     | -     | -            |
+--------------+--------+-------+--------------+

用外部 DNS 配置 OpenStack Neutron

1、为 Designate 服务配置 iptables：

# iptables -I INPUT -p tcp -m multiport --dports 9001 -m comment --comment "designate incoming" -j ACCEPT
       
# iptables -I INPUT -p tcp -m multiport --dports 5354 -m comment --comment "Designate mdns incoming" -j ACCEPT
       
# iptables -I INPUT -p tcp -m multiport --dports 53 -m comment --comment "bind incoming" -j ACCEPT
        
# iptables -I INPUT -p udp -m multiport --dports 53 -m comment --comment "bind/powerdns incoming" -j ACCEPT
       
# iptables -I INPUT -p tcp -m multiport --dports 953 -m comment --comment "rndc incoming - bind only" -j ACCEPT
       
# service iptables save; service iptables restart
# setsebool named_write_master_zones 1

2、 编辑 /etc/neutron/neutron.conf 的 [default] 节：

external_dns_driver = designate

3、 在 /etc/neutron/neutron.conf 中添加 [designate] 节：

[designate]
url = http://{{ CONTROLLER_SERVER_IP }}:9001/v2 ## This end point of designate
auth_type = password
auth_url = http://{{ CONTROLLER_SERVER_IP }}:5000
username = designate
password = rhlab123
project_name = services
project_domain_name = Default
user_domain_name = Default
allow_reverse_dns_lookup = True
ipv4_ptr_zone_prefix_size = 24
ipv6_ptr_zone_prefix_size = 116 

4、编辑 neutron.conf 的 dns_domain：

dns_domain = rhlab.dev.

重启：

# systemctl restart neutron-*

5、在 /etc/neutron/plugins/ml2/ml2_conf.ini 中的组成层 2（ML2）中添加 dns：

extension_drivers=port_security,qos,dns

6、在 Designate 中添加区域：

# openstack zone create –email=admin@rhlab.dev rhlab.dev.

在 rhlab.dev 区域中添加记录：

# openstack recordset create --record '192.168.1.230' --type A rhlab.dev. Test

Designate 现在就安装和配置好了。