Rancher 2.0 Dynamic DNS Controller
The dynamic DNS controller creates the necessary DNS entries to make the following endpoint URLs work:
<http/https>://<$ingress_name>.<$namespace>.<$cluster_id>.<rancher_root_domain>/<$path>
The dynamic DNS controller watches all the ingress resources in the cluster and creates the following DNS entries in <rancher_root_domain>:
<$ingress_name>.<$namespace>.<$cluster_id>.<rancher_root_domain> => [ingress IPs]
When an ingress resource has more than 10 IPs, only 10 IPs will be returned by DNS.
In an RKE cluster, when a node becomes unhealthy and the corresponding nginx ingress resource becomes unavailable, the dynamic DNS controller updates the DNS mapping to remove that node IP from the list.
Every once in a while (default 5m), the dynamic DNS controller will resync nginx ingress resource.
Every once in a while (default 24h), the dynamic DNS controller will renew the domain to refresh Expiration.
Default Settings
| Name | Value |
|---|---|
| Default Ingress Resync Duration | 5 minute |
| Default Domain Renew Duration | 24 hour |
The Rancher DNS server needs to implement the following API:
| Operation | URL | Method/JSON Payload |
|---|---|---|
| Create Domain | /v1/domain | POST Payload: {"hosts": ["1.1.1.1", "2.2.2.2"]} Returns: {"status":200,"msg":"", "token": "abcfdssadasd", "data":{"fqdn":"11111.lb.rancher.cloud","hosts":["1.1.1.1","2.2.2.2"],"expiration":"2018-04-29T10:08:12.906557355Z"}} |
| Get Domain | /v1/domain/<FQDN> | GET [Header] Token: Bearer XXX Returns: {"status":200,"msg":"","data":{"fqdn":"12345678.lb.rancher.cloud","hosts":["1.1.1.1","2.2.2.2"],"expiration":"2018-04-29T09:46:18.078663181Z"}} |
| Renew Domain | /v1/domain/<FQDN>/renew | PUT [Header] Token: Bearer XXX Returns: {"status":200,"msg":"","data":{"fqdn":"12345678.lb.rancher.cloud","hosts":["1.1.1.1","2.2.2.2"],"expiration":"2018-05-29T09:46:18.078663181Z"} |
| Update Domain | /v1/domain/<FQDN> | PUT [Header] Token: Bearer XXX Payload: {"hosts": ["3.3.3.3", "4.4.4.4"]} Returns {"status":200,"msg":"","data":{"fqdn":"12345678.lb.rancher.cloud","hosts":["3.3.3.3","4.4.4.4"],"expiration":"2018-04-30T01:03:40.870506511Z"}} |
| Delete Domain | /v1/domain/<FQDN> | DELETE [Header] Token: Bearer XXX |
The token received in the create domain call should be passed as a bearer token in all subsequent calls to update and delete. The implementation of the DNS service should leverage something like CoreDNS or PowerDNS.
DNS Settings
| Name | Value |
|---|---|
| <rancher_root_domain> | lb.rancher.cloud |
| TTL | 1 minute |
Configuring the following parameters in the global variable settings.
| Name | Value |
|---|---|
| <ingress-ip-domain> | lb.rancher.cloud |
1.Modify <$ingress-ip-domain> to a specified domain: lb.rancher.cloud
2.Create ingress resource and select the following:
