You may have an error message for the Datanode that the vm.max_map_count value is too low. This setting controls the maximum number of memory map areas a process may have. For Graylog to function properly, this value needs to be at least 262144.

To fix this issue, you need to increase the vm.max_map_count value on your host system. You can do this by running the following command on your Linux host:

sudo sysctl -w vm.max_map_count=262144

To make this change permanent, you can add the following line to your sysctl.conf file:

vm.max_map_count=262144

After adding the line, you can apply the changes without restarting the machine by running:

sudo sysctl -p

This will ensure that the vm.max_map_count value is set correctly both immediately and after a system reboot.