DNS zones and DNS custom resolvers

Creating DNS zones without an IBM Cloud DNS Services instance ID

If you do not have an existing IBM Cloud DNS Service instance setup and want to automatically create and manage a new DNS instance ID, then leave the dns_instance_id deployment input value as null during deployment. In this case, the deployment creates a VPC (as necessary), DNS service instance ID, and the respective DNS zones. This process includes associating the new VPC under the appropriate permitted network.

Creating DNS zones with an existing IBM Cloud DNS Services instance ID

If you have an existing VPC with IBM Cloud DNS Service instance ID, provide that service instance ID as the dns_instance_id deployment input value during IBM Spectrum LSF cluster deployment. In this case, since you already have a DNS service instance ID to use, the IBM Cloud cluster deployment skips creating a new DNS service instance, and creates new DNS zones from the dns_domain_names value for the existing DNS service instance. This process automatically associates the new DNS zones to your existing VPC under the permitted network.

Furthermore, if you have an existing IBM Cloud DNS Service instance setup, but want the IBM Spectrum LSF deployment to create a new VPC for your IBM Spectrum LSF cluster, provide the dns_instance_id deployment input value during deployment. The deployment automatically creates a new VPC with your existing DNS service instance, and creates new DNS zones for the existing DNS service instance. This process automatically associates the new VPC under the permitted network.

A VPC cannot be a permitted network for domains of the same name. When you use an existing DNS instance ID, make sure that the DNS domains are not duplicated to avoid association issues; otherwise, you can encounter a message similar to: Error creating PDNS permitted network: The VPC was already associated to the same DNS zone name.

Creating custom resolvers without an existing VPC

If you want a new custom resolver to be created and associated with the newly created VPC for name resolution, then leave the dns_custom_resolver_id deployment input value as null during IBM Spectrum LSF cluster deployment. The deployment process automatically creates a new VPC and a creates and enables a new custom resolver for your cluster.

Creating custom resolvers with an existing VPC

If you already have an existing VPC and the VPC already has a custom resolver that is associated with it, then you can provide that resolver ID for the dns_custom_resolver_id deployment input value during IBM Spectrum LSF cluster deployment. In this case, the deployment automatically uses the existing VPC for all infrastructure creation, and skips creating a new custom resolver.

A single VPC can be associated with only one custom resolver. You can have multiple custom resolvers, but you can associate each one to only a single VPC; otherwise, you can encounter a message similar to: Error reading the custom resolver. The VPC already has a custom resolver. You can view your existing DNS resolver IDs in IBM Cloud DNS Services.