EFA 2.4.5 DNS is not resolving FQDN

[Alberto_Oter]

Hi experts,

Can someone tell if the EFA needs some extra configuration to force the FQDN resolution (nslookup) from a remote DNS?

Here some highlights of the scenario

-I'm trying to add a new entry to efa notification subscribers list, no other subscriber exist currently.

-In my command instead of the address I'm trying to configure FQDN, trying that I'm getting an error:

Command: (efa:extreme)hostname#efa notification subscribers add-syslog-relp --address hostname01-.eng.phone.net --cacert hostname01-ca-combined.pem

Output: Error : Error on registration for a 'relp' handler on endpoint 'hostname01-.eng.phone.net:514'. ERROR: The host from the endpoint URL is not reachable.

-I currently have IP reachability from EFA external Network to the remote DNS server. (ping/tracepath, both works properly).

-If I try to execute a nslookup with the FQDN hostname01-.eng.phone.net I'm getting the following:

;; connection timed out; no servers could be reached

-I add the following inputs if needed:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

systemd-resolve --status
Failed to get global data: Unit dbus-org.freedesktop.resolve1.service not found.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 

Thanks in advance

[Michael_Morey · Accepted solution]

Alberto,

Ultimately, you can use whatever networking service you like on the platform you are using (TPVM/Standalone/OVA) I am using the TPVM with EFA 3.0

EFA does not require DNS to operate and we actually recommend to not use DNS as it has conflicted with Kubernetes in the past (EFA 2.5 - 2.7).  If you wish to use DNS please keep an eye on your pods and if you see them entering into crashloopbackoff, we would recommend removing the DNS entries.

With that, this is how I change the DNS:

Unable to ping a FQDN:

(efa)extreme@tpvm2:~$ ping google.com
ping: google.com: Name or service not known

resolv.conf lists no name-servers:

(efa)extreme@tpvm2:~$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.

Add your nameservers to /etc/resolvconf/resolv.conf.d/head using your favorite editor

* While the file states to not edit manually, the changes will persist through a reload (tested locally)

(efa)extreme@tpvm2:~$ cat /etc/resolvconf/resolv.conf.d/head
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 8.8.4.4
nameserver 8.8.8.8

Restart resolvconf:

(efa)extreme@tpvm2:~$ sudo service resolvconf restart

Verify that the name-servers are automatically populated in /etc/resolv.conf

(efa)extreme@tpvm2:~$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 8.8.4.4
nameserver 8.8.8.8

Validate you can ping a FQDN:

(efa)extreme@tpvm2:~$ ping google.com
PING google.com (172.217.14.238) 56(84) bytes of data.
64 bytes from sea30s02-in-f14.1e100.net (172.217.14.238): icmp_seq=1 ttl=114 time=48.1 ms
64 bytes from sea30s02-in-f14.1e100.net (172.217.14.238): icmp_seq=2 ttl=114 time=52.7 ms
--- google.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 48.124/50.441/52.759/2.328 ms