Check Ethernet card (NIC) supports Wake On LAN:

ethtool eth0 | grep Wake-on

*Make sure that ‘g’ is included as one of the options for ‘Supports Wake-on: ‘ e.g. Supports Wake-on: pumbg
**Substitute eth0 with correct interface

Configure the NIC to wake on MagicPacket:

ethtool -s eth0 wol g

Persist the change by editing /etc/sysconfig/network-scripts/ifcfg-eth0 and appending:

ETHTOOL_OPTS="wol g"

Shutdown and test WOL.

 sed -rne '/Wed Aug 19 21:34:00/,/Wed Aug 19 21:40:00/ p' logfile.log

The timestamp in the log file in this case was in the following format:

Wed Aug 19 21:39:59 2020

keytool -list -v -keystore keystore.ts -storepass PASSWORD

In the main server block (e.g. /etc/nginx/nginx.conf) add the following:

        if ($http_user_agent ~* (AgentName) ) {
        return 403;
        }

Test nginx config and restart:

nginx -t
service nginx restart

To test the agent gets blocked:

curl -I -H 'User-agent: AgentName' localhost/bla

HTTP/1.1 403 Forbidden

It is worth checking the replication factor before modifying:

./path/to/kafka/bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic test-topic

Topic:test-topic        PartitionCount:2        ReplicationFactor:1     Configs:
        Topic: demo-topic       Partition: 0    Leader: 0       Replicas: 0     Isr: 0
        Topic: demo-topic       Partition: 1    Leader: 1       Replicas: 1     Isr: 1

It can be seen here that the replication factor is 1.

To update to a replication factor of e.g. 3 firstly create a json file with a new reassignment plan. Call it e.g. reassignment-plan.json: