what is the command to check zookeeper health check for liveness , readiness probes and to start , stop the zookeeper

Question

i have tried the following commands to check the zookeeper health and its corresponding error i am getting

1. sh -c zookeeper-ready 2181 (error: zookeeper-ready command not found)
2. i have tried all echo commands (error: it is not a file)
3. /apache-zookeeper-3.5.5-bin/bin/zkServer.sh start (error: cannot be able to start)
4. /apache-zookeeper-3.5.5-bin/bin/zkServer.sh stop (error: zookeeper stopping ...... there is no zookeeper to stop)
5. /apache-zookeeper-3.5.5-bin/bin/zkServer.sh status (error: when i am stopping the zookeeper the probe needs to fail for this command but it is not happening. it needs to be done)

and i have used these commands in go file as

    LivenessProbe: &corev1.Probe{
        Handler: corev1.Handler{
            Exec: &corev1.ExecAction{
                Command: []string{"sh",
                    "/apache-zookeeper-3.5.5-bin/bin/zkServer.sh" ,
                    "status",
                },
            },
        },
        InitialDelaySeconds: 30,
        TimeoutSeconds:      5,
    },
    ReadinessProbe: &corev1.Probe{
        Handler: corev1.Handler{
            Exec: &corev1.ExecAction{
                Command: []string{
                    "sh",
                    "/apache-zookeeper-3.5.5-bin/bin/zkServer.sh" ,
                    "status",
                },
            },
        },
        InitialDelaySeconds: 30,
        TimeoutSeconds:      5,
    },

Answer 1

To check liveness and rediness for zookeeper you can use following command

echo "ruok" | timeout 2 nc -w 2 localhost 2181 | grep imok

but make sure to set the env variable ZOO_4LW_COMMANDS_WHITELIST=ruok other wise the the check will fail.

Answer 2

You have to configure

livenessProbe:
      exec:
        command: ['/bin/bash', '-c', 'echo "ruok" | nc -w 2 localhost 2181 | grep imok']
      initialDelaySeconds: 30
      periodSeconds: 10
      timeoutSeconds: 5
      failureThreshold: 6
      successThreshold: 1
    readinessProbe:
      exec:
        command: ['/bin/bash', '-c', 'echo "ruok" | nc -w 2 localhost 2181 | grep imok']
      initialDelaySeconds: 5
      periodSeconds: 10
      timeoutSeconds: 5
      failureThreshold: 6
      successThreshold: 1

For ruok,

Plain kafka

You need to set env. variable

ZOO_4LW_COMMANDS_WHITELIST=rouk

Confluent kafka

KAFKA_OPTS=-Dzookeeper.4lw.commands.whitelist=ruok

Also, You have to change the podManagementPolicy=parallel to start parallel