IPv6 only enabled host connectivity issue

[igarny]

Hey guys
On an Ubuntu 20 host with no configuration for IPv4 there is a problem with retrieving the data for the pS Toolkit UI using Elmond.

IMO the Elmond configuration doesn't take into account the IPv6 specific records as shown in the diagnostic output By default on Ubuntu 20 there is is a difference between IPv4 and IPv6 records for the internal (local) interface.

r75:~$ cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 rrze70

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters


r75:~$ cat /etc/perfsonar/elmond/elmond.json
{
  "ELASTIC_HOSTS": [
    "https://pscheduler_reader:NmV1WfAc56EsJzqhFdqj@localhost:9200"
  ],
  "ELASTIC_PARAMS": {
    "use_ssl": true,
    "ca_certs": "/etc/opensearch/root-ca.pem"
  },
  "PROXY_PATH": "/esmond/perfsonar/archive",
  "FORCE_HTTPS_URLS": true,
  "SUMMARY_WINDOW_ROLLUP_NAMES": {
    "300": "5m",
    "3600": "1h",
    "86400": "1d"
  }
}

the result is: