Starting ZooKeeper and Warden

Starting ZooKeeper and Warden brings up the cluster.

Depending on the options that you specified when running configure.sh, Zookeeper and Warden might already be started.
NOTE
For a DARE-enabled cluster, you can skip this step because you already started the cluster in order to configure disk storage.
To check that Zookeeper is started, use this command on Zookeeper nodes:
systemctl status mapr-zookeeper
To check that Warden is started:
systemctl status mapr-warden
To start the cluster if Zookeeper and Warden are not started:
  1. Start ZooKeeper on all nodes where it is installed, by issuing the following command:
    systemctl start mapr-zookeeper
  2. Start Warden on all nodes:
    systemctl start mapr-warden

For clusters, ensure that Zookeeper has established a quorum. Use the nc command to check.

To install nc, use one of the following commands:
On RHEL: dnf install nmap-ncat
On SLES: zypper install netcat-openbsd
On Ubuntu: apt-get install netcat
To check for a quorum, run:
echo srvr | nc localhost 5181 | grep Mode
This command returns leader or follower if Zookeeper has established a quorum.
NOTE
For a single Zookeeper node (is not part of a cluster), the nc command always returns standalone.