Host(s) Unable to Connect to Management Plane With "Error: getaddrinfo ENOTFOUND

Problem

• Host(s) are unable to remain online from the Management Plane's perspective.
• The following errors are present at /var/log/pf9/comms/comms.log.

[122] [ERROR] sni-http-v1-8158-1 - Server socket for client 87 error: { [Error: getaddrinfo ENOTFOUND customer.platform9.net customer.platform9.net:443]  code: 'ENOTFOUND',  errno: 'ENOTFOUND',  syscall: 'getaddrinfo',  hostname: 'customer.platform9.net',  host: 'customer.platform9.net',  port: 443 }Error: getaddrinfo ENOTFOUND customer.platform9.net customer.platform9.net:443    at errnoException (dns.js:27:10)    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:78:26)

Environment

• Platform9 Managed OpenStack - All Versions

Cause

• The hosts' DNS servers are unable to resolve the Management Plane URL.
• If you’re running Ubuntu 16.10 or later, your DNS resolution will be managed by the systemd-resolved service. If this service is restarted any changes applied in the file /etc/resolv.conf which is a symlink to /run/systemd/resolve/resolv.conf will be lost.

Resolution

1. It will be necessary to contact your DNS provider or internal network team that maintains your environments' DNS server(s) in order to troubleshoot the root cause.
2. If the DNS resolution is managed by systemd-resolved service in Ubuntu 16.10 or later, You can disable the service and create a regular /etc/resolv.conf file.