"LOG","00000","send dummy packet failed, sendto failed: No route to host",

Products

• VMware Tanzu Data Suite
• VMware Tanzu Greenplum
• Pivotal Data Suite Non Production Edition
• VMware Tanzu Data Suite
• Greenplum

Issue/Introduction

After upgrading to 6.27.x or above the following log message is report very frequently: 

"LOG","00000","send dummy packet failed, sendto failed: No route to host",

Grepping the logs shows it is reported multiple times throughout the day:

$ grep -c "send dummy packet failed, sendto failed: No route to host"  gpdb-2024-09-2*.csv
gpdb-2024-09-20_000000.csv:388999
gpdb-2024-09-21_000000.csv:278434
gpdb-2024-09-22_000000.csv:178032
gpdb-2024-09-23_000000.csv:209994
gpdb-2024-09-24_000000.csv:199163
gpdb-2024-09-25_000000.csv:244729
gpdb-2024-09-26_000000.csv:38878
gpdb-2024-09-26_021357.csv:39206

Cause

This is a known issue related to IPv6.

Resolution

Workaround

The recommended workaround is to hardware disable IPv6.

Note: Disabling IPv6 with kernel parameter "net.ipv6.conf.all.disable_ipv6=1" is not sufficient.

As root user modify GRUB and reboot the machine:

1. edit the file /etc/default/grub 
   Add "ipv6.disable=1" to the "GRUB_CMDLINE_LINUX" setting. It should look something like:
   GRUB_CMDLINE_LINUX="ipv6.disable=1 <more options here>..."
   
   
2. Create a backup of the file /boot/grub2/grub.cfg:
   cp /boot/grub2/grub.cfg{,.bkp}
   
   
3. Make new grub.cfg file
   grub2-mkconfig -o /boot/grub2/grub.cfg
   
   
4. Reboot the host

 

Fix

A code fix is currently being developed and will be released in a future version.