StatefulSet
StatefulSet 概述
-
StatefulSet 有状态集合，简称 sts，更适合运行有状态服务 Stateful service
-
StatefulSet 属于通用的有状态应用控制器
-
StatefulSet 强依赖于 Headless Service；即创建 StatefulSet 前 需先创建无头服务
- 因为无头服务可以给每个 pod 定义一个唯一的 service 域名标识，pod间使用这个域名进行反向解析得到目标pod的IP，进而实现 pod 与 pod 间直接通信，而不再经由service调度
-
如果 StatefulSet 需要持久化存储，那么每个实例都需要有自己独立的持久化存储，并且只能是PVC格式
-
StatefulSet 的每个 Pod 维护了一个有粘性的 ID。这些 Pod 是基于相同的规约来创建的， 但是不能相互替换：无论怎么调度，每个 Pod 都有一个永久不变的 ID。
有状态服务
- 多个实例彼此间不可以互相取代则为有状态服务
- 有状态服务可以说是 需要数据存储功能的服务、或者指多线程类型的服务，队列等。
- 状态的服务中的每个pod都有特定的名称和网络标识，比如pod名是由statefulSet名+有序的数字组成（0、1、2..）
- statefulset_name-mysql-0、statefulset_name-mysql-1、statefulset_name-mysql-2
常见的有状态服务：
- MySQL、MongoDB、zookeeper、kafka 等…
StatefulSet 部署应用
- 顺序部署，假设三个副本，则 app-0 –> app-1 –> app-2
其他说明：
- 有的应用须严格按照先后顺序部署；例如：MySQL 集群，只能先部署主节点，再部署从节点，顺序不能颠倒。
- 有的应用部署时无需考虑部署的先后顺序；例如：zookeeper，因其内部自有leader选举协议，因此哪个节点先后启动都一样
StatefulSet 扩容应用
- 顺序扩容，例如：目前版本 app-0、app-1、app-2，再扩容两个应用则 app-3 –> app-4
StatefulSet 缩容应用
-
逆序缩容，例如：目前版本 app-0、app-1、app-2，缩容顺序为先删除app-2，再删除app-1
-
Statefulset 在有实例不健康的情况下不允许缩容
StatefulSet 缩容任何时候只会操作 一个 pod 实例，所以有状态应用的缩容不会很迅速。
- 举例来说：一个分布式存储应用若同时下线多个节点 ，则可能导致其数据丢失 。
- 比如说一个数据项副本数设置为 2 的数据存储应用， 若 同时有两个节点下线，一份数据记录就会丢失，如果它正好保存在这两个节点上 。
- 若缩容是线性的 ，则分布式存储应用就有时间把丢失的副本复制到其他节点 ，保证数据不会丢失。
StatefulSet 更新应用
StatefulSet.spec.updateStrategy.type.Rollingupdate
- 逆序更新，默认值，例如：目前版本 app-0、app-1、app-2，则会以 app-2 –> app-1 –> app-0 的顺序逆序更新
- 并且只能先减Pod，再加Pod
- 可以使用
StatefulSet.spec.updateStrategy.type.rollingUpdate.partition指定分区指示索引值，只有编号大于partition的pod才会被逆序更新（类似于金丝雀发布）；默认为0，即大于0的Pod都会逆序更新
StatefulSet.spec.updateStrategy.type.OnDelete
- 删除所有Pod后再更新
生产中运行 StatefulSet
- 自行创建比较繁琐并且不便于管理，所有应该使用Operator来部署与管理有状态应用
- Operator 是服务提供商开发的 StatefulSet
- https://operatorhub.io/
- https://github.com/operator-framework/awesome-operators
参考文档
- https://kubernetes.io/zh-cn/docs/concepts/workloads/controllers/statefulset/
- https://kubernetes.io/zh-cn/docs/tutorials/stateful-application/basic-stateful-set/
- https://kubernetes.io/zh-cn/docs/tutorials/stateful-application/cassandra/
StatefulSet Explain
apiVersion: apps/v1 # API群组及版本；
kind: StatefulSet # 资源类型的特有标识
metadata:
name <string> # 资源名称，在作用域中要唯一
namespace <string> # 名称空间；StatefulSet隶属名称空间级别
spec:
replicas <integer> # 期望的Pod副本数，默认为1
selector <object> # 标签选择器，须匹配Pod模板中的标签，必选字段
template <object> # Pod模板对象，必选字段
revisionHistoryLimit <integer> # 滚动更新历史记录数量，默认为10
updateStrategy <Object> # 滚动更新策略
type <string> # 滚动更新类型，可用值有OnDelete和Rollingupdate，OnDelete删除所有Pod后再更新
rollingUpdate <Object> # 滚动更新参数，专用于RollingUpdate类型，只能定义partition
partition <integer> # 分区指示索引值，只有编号大于partition的pod才会被逆序更新（类似于金丝雀发布）；默认为0，即大于0的Pod都会被逆序更新
serviceName <string> # 相关的Headless Service的名称，必选字段
volumeClaimTemplates <[]Object> # 存储卷申请模板
apiVersion <string> # PVC资源所属的API群组及版本，可省略
kind <string> # PVC资源类型标识，可省略
metadata <Object> # 卷申请模板元数据
spec <Object> # 期望的状态，可用字段同PVC
podManagementPolicy <string> # 定义Pod创建和删除策略，OrderedReady表示顺序递增创建和逆序递减删除，Parallel表示并行模式创建和删除，默认值OrderedReadyStatefulSet Example
范例：运行 MySQL
目标：
- 1、statefulset跑一个mysql实例，使用secret保存账号、密码、数据库名称等信息，使用volumeClaimTemplate请求创建PVC，并持久存储数据；
- 2、Deployment跑两个wordpress实例，从secret中加载数据库名称、用户名和密码等信息（调用上面使用statefulset创建的MySQL实例），基于支持RWX访问模式的PVC保存页面资源。
范例：运行 zookeeper 集群
- 参考文档：https://kubernetes.io/zh-cn/docs/tutorials/stateful-application/zookeeper/
说明
目前有以下几个问题：
-
zookeeper-service.yaml 中 如果使用 type: NodePort 并且定义 nodePort: 32181，那么在 zookeeper 中使用 service 的名称来定义其它 zookeeper 节点的地址将无法完成 leader 选举，除非使用 Pod 的 IP，但使用 Pod 的 IP 又无法实现当 Pod 宕机 IP 被回收所导致的高可用问题
-
zookeeper-service.yaml 中 如果使用 type: ClusterIP 并且定义 clusterIP: None，虽然可以完成 leader 的选举，但又无法实现从外部访问 zookeeper cluster
-
另外镜像还需修改，因为各集群节点需手工添加：
-
# cat /zookeeper/apache-zookeeper-3.8.0-bin/conf/zoo.cfg dataDir=/data/zookeeper dataLogDir=/data/zookeeper/logs tickTime=2000 initLimit=10 syncLimit=5 clientPort=2181 server.1=zookeeper-service-1.zookeeper.svc.kubecluster.local:2888:3888 server.2=zookeeper-service-2.zookeeper.svc.kubecluster.local:2888:3888 server.3=zookeeper-service-3.zookeeper.svc.kubecluster.local:2888:3888
NFS
- 安装过程省略
# 创建共享目录
# mkdir -p /nfs_data/zookeeper/zk{1..3}
# 定义共享目录
# vim /etc/exports
...
/nfs_data/zookeeper/ *(rw,no_root_squash)
# 重载配置文件
# exportfs -r
# 查看共享结果
# showmount -e 10.0.0.103
Export list for 10.0.0.103:
/nfs_data/zookeeper *
...Dockerfile
- 制作 zookeeper 镜像
相关文件
- 注意：entrypoint.sh 脚本需要加执行权限
# ll /data/dockerfile/zookeeper/
total 12892
drwxr-xr-x 2 root root 4096 Jul 14 14:58 ./
drwxr-xr-x 7 root root 4096 Jul 14 14:45 ../
-rw-r--r-- 1 root root 13185104 Jun 11 14:05 apache-zookeeper-3.8.0-bin.tar.gz
-rw-r--r-- 1 root root 0 Jul 14 14:45 Dockerfile
-rwxr-xr-x 1 root root 1860 Jul 14 14:58 entrypoint.sh*apache-zookeeper-3.8.0-bin.tar.gz
# sha512sum /data/dockerfile/zookeeper/apache-zookeeper-3.8.0-bin.tar.gz
d66e3a40451f840406901b2cd940992b001f92049a372ae48d8b420891605871cd1ae5f6cceb3b10665491e7abef36a4078dace158bd1e0938fcd3567b5234ca /data/dockerfile/zookeeper/apache-zookeeper-3.8.0-bin.tar.gz
# 官方提供的校验码
d66e3a40451f840406901b2cd940992b001f92049a372ae48d8b420891605871cd1ae5f6cceb3b10665491e7abef36a4078dace158bd1e0938fcd3567b5234ca-apache-zookeeper-3.8entrypoint.sh
- offical
#!/bin/bash
#
#********************************************************************
#Author: xiangzheng
#QQ: 767483070
#Date: 2022-07-14
#FileName： entrypoint.sh
#URL: https://www.xiangzheng.vip
#Email: rootroot25@163.com
#Description： The test script
#Copyright (C): 2022 All rights reserved
#********************************************************************
set -e
# Allow the container to be started with `--user`
if [[ "$1" = 'zkServer.sh' && "$(id -u)" = '0' ]]; then
chown -R zookeeper "$ZOO_DATA_DIR" "$ZOO_DATA_LOG_DIR" "$ZOO_LOG_DIR"
exec gosu zookeeper "$0" "$@"
fi
# Generate the config only if it doesn't exist
if [[ ! -f "$ZOO_CONF_DIR/zoo.cfg" ]]; then
CONFIG="$ZOO_CONF_DIR/zoo.cfg"
{
echo "dataDir=$ZOO_DATA_DIR"
echo "dataLogDir=$ZOO_DATA_LOG_DIR"
echo "tickTime=$ZOO_TICK_TIME"
echo "initLimit=$ZOO_INIT_LIMIT"
echo "syncLimit=$ZOO_SYNC_LIMIT"
echo "autopurge.snapRetainCount=$ZOO_AUTOPURGE_SNAPRETAINCOUNT"
echo "autopurge.purgeInterval=$ZOO_AUTOPURGE_PURGEINTERVAL"
echo "maxClientCnxns=$ZOO_MAX_CLIENT_CNXNS"
echo "standaloneEnabled=$ZOO_STANDALONE_ENABLED"
echo "admin.enableServer=$ZOO_ADMINSERVER_ENABLED"
} >> "$CONFIG"
if [[ -z $ZOO_SERVERS ]]; then
ZOO_SERVERS="server.1=localhost:2888:3888;2181"
fi
for server in $ZOO_SERVERS; do
echo "$server" >> "$CONFIG"
done
if [[ -n $ZOO_4LW_COMMANDS_WHITELIST ]]; then
echo "4lw.commands.whitelist=$ZOO_4LW_COMMANDS_WHITELIST" >> "$CONFIG"
fi
for cfg_extra_entry in $ZOO_CFG_EXTRA; do
echo "$cfg_extra_entry" >> "$CONFIG"
done
fi
# Write myid only if it doesn't exist
if [[ ! -f "$ZOO_DATA_DIR/myid" ]]; then
echo "${ZOO_MY_ID:-1}" > "$ZOO_DATA_DIR/myid"
fi
exec "$@"- test
#!/bin/bash
#
#********************************************************************
#Author: xiangzheng
#QQ: 767483070
#Date: 2022-07-14
#FileName： entrypoint.sh
#URL: https://www.xiangzheng.vip
#Email: rootroot25@163.com
#Description： The test script
#Copyright (C): 2022 All rights reserved
#********************************************************************
set -e
# 仅当配置文件不存在时生成配置文件
if [[ ! -f "${ZOO_WORK_DIR}/conf/zoo.cfg" ]]; then
CONFIG="${ZOO_WORK_DIR}/conf/zoo.cfg"
{
echo "dataDir=${ZOO_DATA_DIR}"
echo "dataLogDir=${ZOO_DATA_LOG_DIR}"
echo "tickTime=${ZOO_TICK_TIME}"
echo "initLimit=${ZOO_INIT_LIMIT}"
echo "syncLimit=${ZOO_SYNC_LIMIT}"
echo "clientPort=${ZOO_CLI_PORT}"
} >> "$CONFIG"
fi
# 通过循环方式添加集群节点
for ID in `seq ${CLUSTER_NUM}`;do
echo "server.${ID}=10.0.0.100:2888:3888" >> $CONFIG
done
# 本节点ID
echo ${MY_ID} > /data/zookeeper/myid
/usr/bin/tail -f /etc/hostsDockerfile
- 基于定制的 jdk 镜像制作 zookeeper 镜像
- /data/dockerfile/zookeeper/Dockerfile
FROM harbor.xiangzheng.vip/baseimages-app/jdk-8u333-base-ubuntu:1.0
LABEL version="1.0" \
maintainer="XiangZheng <767483070@qq.com>"
ADD apache-zookeeper-3.8.0-bin.tar.gz /zookeeper/
# 指定工作目录
ENV ZOO_WORK_DIR=/zookeeper/apache-zookeeper-3.8.0-bin \
# zookeeper 数据保存目录
ZOO_DATA_DIR=/data/zookeeper \
# zookeeper 数据日志保存目录
ZOO_DATA_LOG_DIR=/data/zookeeper/logs\
# zookeeper 节点间心跳节点检测时间间隔，毫秒为单位
ZOO_TICK_TIME=2000 \
# 集群中的 leader 与 follower服务器的初始连接心跳检测次数
# 此处的10表示 当初始连接超过10个2000毫秒后此follower将视为不可用
ZOO_INIT_LIMIT=10 \
# 集群中的 leader 与 follower服务器的连接后，后期的心跳检测次数
# 此处的5表示 当后续连接超过5个2000毫秒后此follower将视为不可用
ZOO_SYNC_LIMIT=5 \
# 监听客户端连接的端口
ZOO_CLI_PORT=2181
RUN set -eux; \
# 定义启动用户
groupadd -r zookeeper --gid=2181; \
useradd -r -g zookeeper --uid=2181 zookeeper; \
chown -R zookeeper.zookeeper ${ZOO_WORK_DIR}; \
# 创建数据存放目录
mkdir -p /data/zookeeper/logs
WORKDIR ${ZOO_WORK_DIR}
EXPOSE 2181 2888 3888 8080
COPY entrypoint.sh /
#ENTRYPOINT ["/usr/bin/tail","-f","/etc/hosts"]
ENTRYPOINT ["/entrypoint.sh"]
#CMD ["zkServer.sh", "start-foreground"]测试：
docker run --rm -d --name zookeeper zookeeper-3.8.0-jdk-8u333:1.0 ; docker exec -it zookeeper bash
docker stop zookeeper
docker images |grep zoo ; docker ps -a |grep zoo
server.1=zookeeper-service-1.zookeeper.svc.kubecluster.local:2888:3888
server.2=zookeeper-service-2.zookeeper.svc.kubecluster.local:2888:3888
server.3=zookeeper-service-3.zookeeper.svc.kubecluster.local:2888:3888
server.1=zookeeper-service-1:2888:3888
server.2=zookeeper-service-2:2888:3888
server.3=zookeeper-service-3:2888:3888
server.1=192.168.3.144:2888:3888
server.2=192.168.12.58:2888:3888
server.3=192.168.8.64:2888:3888
# docker run --rm -e CLUSTER_NUM=3 -e MY_ID=1 -d --name zookeeper zookeeper-3.8.0-jdk-8u333:1.0 ; docker exec -it zookeeper bash
# cat conf/zoo.cfg
dataDir=/data/zookeeper
dataLogDir=/data/zookeeper/logs
tickTime=2000
initLimit=10
syncLimit=5
clientPort=2181
server.1=10.0.0.100:2888:3888
server.2=10.0.0.100:2888:3888
server.3=10.0.0.100:2888:3888
# cat /data/zookeeper/myid
1- 配置文件
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/data/zookeeper
clientPort=2181
# cat zoo.cfg.bak
# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/tmp/zookeeper
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# https://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
## Metrics Providers
#
# https://prometheus.io Metrics Exporter
#metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider
#metricsProvider.httpHost=0.0.0.0
#metricsProvider.httpPort=7000
#metricsProvider.exportJvmInfo=true构建镜像并上传到 harbor
- 构建镜像
docker build -t zookeeper-3.8.0-jdk-8u333:1.0 .-
在 harbor 创建项目，并命名为 如：baseimages-os，访问级别设为公开
-
打标签然后上传到 harbor
# 打标签
docker tag zookeeper-3.8.0-jdk-8u333:1.0 harbor.xiangzheng.vip/baseimages-os/zookeeper-3.8.0-jdk-8u333:1.0
# 上传
docker push harbor.xiangzheng.vip/baseimages-os/zookeeper-3.8.0-jdk-8u333:1.0yaml
- k8s 编排 zookeeper 镜像
相关文件
# tree /data/yaml/zookeeper/
/data/yaml/zookeeper/
├── pv
│ ├── zookeeper-pvc.yaml
│ └── zookeeper-pv.yaml
├── zookeeper-deployment.yaml
├── zookeeper-namespace.yaml
└── zookeeper-service.yaml
1 directory, 5 fileszookeeper-namespace.yaml
# vim /data/yaml/zookeeper/zookeeper-namespace.yaml
apiVersion: v1
kind: Namespace
metadata:
name: zookeeper验证
# kubectl apply -f /data/yaml/zookeeper/zookeeper-namespace.yaml
namespace/zookeeper created
# kubectl get namespaces
NAME STATUS AGE
...
zookeeper Active 3m37szookeeper-pv.yaml
# vim /data/yaml/zookeeper/zookeeper-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: zookeeper-pv-1
namespace: zookeeper
spec:
capacity:
storage: 30Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
nfs:
path: "/nfs_data/zookeeper/zk1"
server: 10.0.0.103
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: zookeeper-pv-2
namespace: zookeeper
spec:
capacity:
storage: 30Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
nfs:
path: "/nfs_data/zookeeper/zk2"
server: 10.0.0.103
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: zookeeper-pv-3
namespace: zookeeper
spec:
capacity:
storage: 30Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
nfs:
path: "/nfs_data/zookeeper/zk3"
server: 10.0.0.103验证
# kubectl apply -f /data/yaml/zookeeper/zookeeper-pv.yaml
persistentvolume/zookeeper-pv-1 created
persistentvolume/zookeeper-pv-2 created
persistentvolume/zookeeper-pv-3 created
# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
zookeeper-pv-1 30Gi RWO Retain Available 15s
zookeeper-pv-2 30Gi RWO Retain Available 15s
zookeeper-pv-3 30Gi RWO Retain Available 15szookeeper-service.yaml
- 下面创建了两个service，类型都为 ClusterIP(不写则默认为ClusterIP)，ClusterIP 表示只能在群集中访问该 service。
- zookeeper-election 为无头 service，表示不分配 ClusterIP，但是可以通过 service 来进行访问，请求会到达目标 Pod 的实际 IP ，而非 service 的 ClusterIP。
# vim /data/yaml/zookeeper/zookeeper-service.yaml
apiVersion: v1
kind: Service
metadata:
name: zookeeper-election
namespace: zookeeper
spec:
ports:
- port: 2888
name: server
- port: 3888
name: leader-election
clusterIP: None
selector:
app: zookeeper
---
apiVersion: v1
kind: Service
metadata:
name: zookeeper-client
namespace: zookeeper
spec:
ports:
- port: 2181
name: client
selector:
app: zookeeper验证
# kubectl apply -f zookeeper-service.yaml
service/zookeeper-election created
service/zookeeper-client created
# kubectl get service -n zookeeper
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
zookeeper-client ClusterIP 192.168.8.87 <none> 2181/TCP 7s
zookeeper-election ClusterIP None <none> 2888/TCP,3888/TCP 7szookeeper-pdb.yaml
# vim /data/yaml/zookeeper/zookeeper-pdb.yaml
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
name: zookeeper-pdb
spec:
selector:
matchLabels:
app: zookeeper
maxUnavailable: 1验证
# kubectl apply -f /data/yaml/zookeeper/zookeeper-pdb.yaml
poddisruptionbudget.policy/zookeeper-pdb created
# kubectl get poddisruptionbudgets.policy
NAME MIN AVAILABLE MAX UNAVAILABLE ALLOWED DISRUPTIONS AGE
zookeeper-pdb N/A 1 0 43szookeeper-statefulset.yaml
# vim /data/yaml/zookeeper/zookeeper-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: zookeeper
namespace: zookeeper
spec:
selector:
matchLabels:
app: zookeeper
serviceName: zookeeper-election
replicas: 3
updateStrategy:
type: RollingUpdate
podManagementPolicy: OrderedReady
template:
metadata:
labels:
app: zookeeper
spec:
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: "app"
operator: In
values:
- zookeeper
topologyKey: "kubernetes.io/hostname"
containers:
- name: kubernetes-zookeeper
imagePullPolicy: IfNotPresent
image: "mirrorgooglecontainers/kubernetes-zookeeper:1.0-3.4.10"
resources:
requests:
memory: "1Gi"
cpu: "0.5"
ports:
- containerPort: 2181
name: client
- containerPort: 2888
name: server
- containerPort: 3888
name: leader-election
command:
- sh
- -c
- "start-zookeeper \
--servers=3 \
--data_dir=/var/lib/zookeeper/data \
--data_log_dir=/var/lib/zookeeper/data/log \
--conf_dir=/opt/zookeeper/conf \
--client_port=2181 \
--election_port=3888 \
--server_port=2888 \
--tick_time=2000 \
--init_limit=10 \
--sync_limit=5 \
--heap=512M \
--max_client_cnxns=60 \
--snap_retain_count=3 \
--purge_interval=12 \
--max_session_timeout=40000 \
--min_session_timeout=4000 \
--log_level=INFO"
readinessProbe:
exec:
command:
- sh
- -c
- "zookeeper-ready 2181"
initialDelaySeconds: 10
timeoutSeconds: 5
livenessProbe:
exec:
command:
- sh
- -c
- "zookeeper-ready 2181"
initialDelaySeconds: 10
timeoutSeconds: 5
volumeMounts:
- name: datadir
mountPath: /var/lib/zookeeper
securityContext:
runAsUser: 1000
fsGroup: 1000
volumeClaimTemplates:
- metadata:
name: datadir
spec:
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 10Gi测试
- 目前还需手动执行
/zookeeper/apache-zookeeper-3.8.0-bin/bin/zkServer.sh start
root@zookeeper-1-deployment-749db8476c-bbmlh:~# /zookeeper/apache-zookeeper-3.8.0-bin/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /zookeeper/apache-zookeeper-3.8.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower
root@zookeeper-2-deployment-55bb4f459c-8rtqk:~# /zookeeper/apache-zookeeper-3.8.0-bin/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /zookeeper/apache-zookeeper-3.8.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: leader
root@zookeeper-3-deployment-847d65c495-t5jxn:~# /zookeeper/apache-zookeeper-3.8.0-bin/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /zookeeper/apache-zookeeper-3.8.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower