# Project architecture DNS operators are a family of charms used to integrate a fully functional DNS solution in [Juju](https://juju.is/). The core charm is the bind-operator, which acts as a primary DNS server. The underlying workload uses [Bind](https://bind9.readthedocs.io), packaged as a snap with other tooling to help administer it from the charm perspective. The following diagram shows how these charms are intended to be used with other charms: The bind-operator is usually deployed with dns-policy to enable human and/or automated approval of incoming DNS record requests. The workload of dns-policy is a Django application packaged as a snap with additional tooling. Since the workloads of both bind-operator and dns-policy are snaps, they can work on the same machine. It was therefore decided to make dns-policy a subordinate charm. The following diagram shows the interactions between bind-operator, dns-policy, and external components of a typical deployment of the DNS charms: After having deployed and integrated all the DNS charms in one model, you should see the following output with `juju status --relations`: `user@host:~$ ``juju status --relations` ```text Model Controller Cloud/Region Version SLA Timestamp machine lxd localhost/localhost 3.6.5 unsupported 13:14:27-04:00 App Version Status Scale Charm Channel Rev Exposed Message bind active 3 bind latest/edge 77 no active dns-integrator-operator active 1 dns-integrator-operator 0 no dns-policy active 3 dns-policy latest/edge 1 no postgresql 14.15 active 1 postgresql 14/stable 553 no Unit Workload Agent Machine Public address Ports Message bind/0* active idle 0 10.227.61.237 53/tcp 53/udp active dns-policy/0* active idle 10.227.61.237 8080/tcp bind/1 active idle 3 10.227.61.162 53/tcp 53/udp dns-policy/1 active idle 10.227.61.162 8080/tcp bind/2 active idle 4 10.227.61.3 53/tcp 53/udp dns-policy/2 active idle 10.227.61.3 8080/tcp dns-integrator-operator/0* active idle 1 10.227.61.161 postgresql/0* active idle 2 10.227.61.146 5432/tcp Primary Machine State Address Inst id Base AZ Message 0 started 10.227.61.237 juju-cd7a0a-0 ubuntu@22.04 Running 1 started 10.227.61.161 juju-cd7a0a-1 ubuntu@22.04 Running 2 started 10.227.61.146 juju-cd7a0a-2 ubuntu@22.04 Running 3 started 10.227.61.162 juju-cd7a0a-3 ubuntu@22.04 Running 4 started 10.227.61.3 juju-cd7a0a-4 ubuntu@22.04 Running Integration provider Requirer Interface Type Message bind:bind-peers bind:bind-peers bind-instance peer bind:dns-record dns-policy:dns-record-requirer dns_record subordinate dns-policy:dns-record-provider dns-integrator-operator:dns-record dns_record regular postgresql:database dns-policy:database postgresql_client regular postgresql:database-peers postgresql:database-peers postgresql_peers peer postgresql:restart postgresql:restart rolling_op peer postgresql:upgrade postgresql:upgrade upgrade peer ``` You can here observe that the DNS policy charm is a subordinate one: It will be deployed on the same machine as the Bind charm as soon as it is integrated to it.