@Michael Bronson You can safely delete them ... View more

@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 ... View more

@Michael Bronson The disk is already unusable go-ahead run fsck with a -y option to repair it 🙂 see above Either way you will have to replace that dirty disk anyways! ... View more

@Michael Bronson Ambari provides an option as following to change the hostnames for various hosts: # ambari-server update-host-names host_names_changes.json . In this case we will need to create a JSON file as mentioned in the doc: https://docs.hortonworks.com/HDPDocuments/Ambari-2.6.0.0/bk_ambari-administration/content/ch_changing_host_names.html { "cluster1" : { "c6400.ambari.apache.org" : "c6410.ambari.apache.org", "c6401.ambari.apache.org" : "c6411.ambari.apache.org", .... } } . NOTE: Please make sure to not have Mixed case hostname OR Uppercase Hostname. Please keep all hostnames in Lowercase else you might encounter some issues. ... View more