Set Explicit DNS Hostnames and IP Mappings

IN THIS ARTICLE

Outlines how to set user-configured hostnames and IP mappings in Qumulo Core

REQUIREMENTS

• Qumulo Core version 2.11.2 or higher

DETAILS

System administrators can set explicit DNS hostname/IP mappings on a cluster, which can be useful in environments where the DNS server is overriding the desired configuration for the cluster and an administrator wants to explicitly configure Qumulo nodes to bypass the DNS-provided mappings. The administrator can provide explicit mappings (either via stdin or as a JSON file) by using the following qq command:

qq dns_set_lookup_overrides --[file | stdin]

IMPORTANT! These rules override any lookup results from the configured DNS servers and serve as static mappings between IP address and hostname.

Overrides can be provided as a vector of JSON objects, as shown in the below example:

qq dns_set_lookup_overrides --file test.json

qq dns_get_lookup_overrides 
{
    "lookup_overrides": [
        { "ip_address": "1.2.3.4", "aliases": ["a.foo.com", "foo.com"]}],
        { "ip_address": "1:2:3:4:5:6:7:8", "aliases": ["b.bar.com", "bar.com"]}
    ]
}

The first alias provided for each IP address is considered the canonical hostname for resolution purposes (e.g., a resolution of 1.2.3.4 to a hostname will always return "a.foo.com").

Once you’ve replaced the configured set of DNS lookup overrides, you can verify the configuration via IP addresses (separated by spaces) using:

qq dns_resolve_ips --ips IP IP

The output displays your explicit DNS configuration:

qq dns_resolve_ips --ips 1.2.3.4
[
    {
    "hostname": "a.foo.com", 
    "ip_address": "1.2.3.4", 
    "result": "OK"
    }
]

To verify the configuration, include the hostnames in the following command:

qq dns_resolve_hostnames --hosts hostname

The output displays the DNS configuration:

qq dns_resolve_hostnames --hosts foo.com
[
    {
    "hostname": "foo.com", 
    "ip_addresses": [
    "1.2.3.4"
    ], 
    "result": "OK"
    }
]

To view the current DNS overrides, use the following command:

qq dns_get_lookup_overrides

{
 "lookup_overrides": [
    {
    "aliases": [
        "a.foo.com", 
        "foo.com"
    ], 
    "ip_address": "1.2.3.4"
    }, 
    {
        "aliases": [
        "b.bar.com", 
        "bar.com"
    ], 
    "ip_address": "1:2:3:4:5:6:7:8"
    }
    ]
}

RESOLUTION

You should now be able to configure explicit DNS hostnames and IP mappings in Qumulo Core

ADDITIONAL RESOURCES

QQ CLI: Networks and IP Addresses

User-Defined Identity Mappings

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