Dose avahi-daemon should be running on ambari cluster machines?

[#1]

we have ambari cluster machines , HDP - 2.6.X

we want to know the opinion of hortonworks about the avahi service

dose this service should be disable or enable on ambari cluster machines ( master / workers / kafka ) ?

note - we want to disable this service especially on the data-node machines ( workers ) , because we think that this service could be the reason of OS restart ,

for now this service is enable and running on all our machines in the ambari cluster

reference - https://www.systutorials.com/docs/linux/man/8-avahi-daemon/

service avahi-daemon status
Redirecting to /bin/systemctl status  avahi-daemon.service
● avahi-daemon.service - Avahi mDNS/DNS-SD Stack
   Loaded: loaded (/usr/lib/systemd/system/avahi-daemon.service; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2018-04-25 18:52:11 UTC; 17min ago

[#2]

I want to add that in /var/log/message file we see a million messages as

Apr 25 00:08:32 worker02 avahi-daemon[953]: Invalid response packet from host 91.61.42.241.
Apr 25 00:08:32 worker02 avahi-daemon[953]: Invalid response packet from host 91.61.60.61.
Apr 25 00:08:32 worker02 avahi-daemon[953]: Invalid response packet from host 91.61.35.160.
Apr 25 00:08:32 worker02 avahi-daemon[953]: Invalid response packet from host 91.61.22.128.
Apr 25 00:08:32 worker02 avahi-daemon[953]: Invalid response packet from host 91.61.56.231.
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[#3]

@Michael Bronson

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. This enables you to plug your laptop or computer into a network and instantly be able to view other people who you can chat with, find printers to print to or find files being shared. Compatible technology is found in Apple MacOS X (branded Bonjour and sometimes Zeroconf)

The two big benefits of Avahi are name resolution & finding printers, but on a server, in a managed environment, it's of little value.

You may want to run the following

systemctl disable avahi-daemon.socket avahi-daemon.service 

Be aware though that the above will disable avahi only temporarily. To prevent automatic re-enabling, it needs to be masked:

systemctl mask avahi-daemon.socket avahi-daemon.service 

Hope that helps

[#4]

Hi Geoffrey , when we build a new hadoop cluster - then dose hortonworks recomended to disable/enable this service ?

[#5]

we ask about this service , because we think the data-node machines have issues when this service is ruining , we see unexpected reboot on workers machines , and million messages in /var/log/messages file about avahi-daemon , so lets minimze the quastion can we be sure about disable this service only on worklers machines ?

[#6]

I want to say additionally , that we use DNS server for manage all hosts in the cluster

[#7 · Accepted solution]

@Michael Bronson

The Avahi daemon is present by default and allows you to discover network resources. No hortonworks documentation talks about it just because I think it trivial.

Do you NEED it? No, AFAIK nobody absolutely needs this, it's a recent technology and the networks have worked before this. It can be convenient though on networks available to the public, but if you administer your network you know where services are.

The only services that affect HDP are documented below especially the last 4

• Set Up Password-less SSH
• Set Up Service User Accounts
• Enable NTP on the Cluster and on the Browser Host
• Check DNS and NSCD
• Configuring iptables
• Disable SELinux and PackageKit and check the umask Value

DNS should work without Avahi, disable on a couple of nodes you will see the seervice still running fine