Manage Non-ICE ClusterWare Entities#

You can configure ICE ClusterWare™ to be aware of entities outside of those created by the ClusterWare platform, such as file servers, database servers, power distribution systems, or network gateways that interact with ClusterWare nodes. For example, a compute node could mount a file system from server fs001, but it needs to know the IP address of fs001. Use scyld-clusterctl with the hosts subcommand to manage these entities.

The hosts subcommand can take on a few different forms.

Create a DNS A record for a host with an IPv4 address:

scyld-clusterctl hosts create name=fs001 ip=10.99.88.77 type=arec

Create a DNS SRV record for a service running on a specified host and port:
```
scyld-clusterctl hosts create name=slurmctld_backup port=6817 proto=tcp service=slurmctld domain=cluster.local target=backuphostname type=srvrec priority=20
```
In this example, a name is provided for the database record (slurmctld_backup) and separately the names of the service (slurmctld) and the target (backuphostname) are specified separately.
Create a DNS A record and a DHCP record for a host with an IPv4 address:
```
scyld-clusterctl hosts create name=fs002 ip=10.99.88.78 type=arec mac=11:22:33:44:55:66
```
In this example, a DNS entry is made for the host (as with #1) and a separate DHCP record is made to match the MAC address to the name and IP address. This allows the fs002 server to boot from the CW DHCP server, picking up the relevant network information that it needs to connect to the network.

The hosts subcommand supports both IPv4 and IPv6 addresses. Per the DNS specs, A records are for IPv4 addresses and AAAA records are used for IPv6 addresses. Also per the DNS specs, an SRV record should be fully resolvable by the DNS server itself and should not return names for which it does not have an A/AAAA record for. Practically speaking, this means that the “target” field of an SRV record should either be an IP-address or should be specified by another scyld-clusterctl hosts entry for the A/AAAA record.