如何在Debian上实现Zookeeper高可用

在Debian上实现Zookeeper高可用（HA）需要部署多个Zookeeper实例，并配置它们形成一个集群。以下是详细的步骤：

1. 安装Zookeeper

首先，确保你的Debian系统已经更新到最新状态：

sudo apt update
sudo apt upgrade

然后，安装Zookeeper：

sudo apt install zookeeper zookeeperd

2. 配置Zookeeper集群

你需要为每个Zookeeper实例创建一个配置文件。假设你有三个Zookeeper实例，分别命名为zoo1, zoo2, 和 zoo3。

创建数据目录和日志目录

为每个实例创建数据目录和日志目录：

sudo mkdir -p /var/lib/zookeeper/zoo1
sudo mkdir -p /var/log/zookeeper/zoo1

sudo mkdir -p /var/lib/zookeeper/zoo2
sudo mkdir -p /var/log/zookeeper/zoo2

sudo mkdir -p /var/lib/zookeeper/zoo3
sudo mkdir -p /var/log/zookeeper/zoo3

配置文件

为每个实例创建一个配置文件，例如/etc/zookeeper/conf/zoo1.cfg，/etc/zookeeper/conf/zoo2.cfg，和/etc/zookeeper/conf/zoo3.cfg。

以zoo1.cfg为例：

tickTime=2000
dataDir=/var/lib/zookeeper/zoo1
clientPort=2181
initLimit=5
syncLimit=2
server.1=zoo1:2888:3888
server.2=zoo2:2888:3888
server.3=zoo3:2888:3888

以zoo2.cfg为例：

tickTime=2000
dataDir=/var/lib/zookeeper/zoo2
clientPort=2182
initLimit=5
syncLimit=2
server.1=zoo1:2888:3888
server.2=zoo2:2888:3888
server.3=zoo3:2888:3888

以zoo3.cfg为例：

tickTime=2000
dataDir=/var/lib/zookeeper/zoo3
clientPort=2183
initLimit=5
syncLimit=2
server.1=zoo1:2888:3888
server.2=zoo2:2888:3888
server.3=zoo3:2888:3888

3. 启动Zookeeper实例

为每个实例创建一个启动脚本。

zoo1启动脚本

创建/etc/init.d/zookeeper1：

#!/sbin/openrc-run
# Copyright 2023 Your Company Name
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

description="Zookeeper server 1"

command="/usr/bin/zkServer.sh"
command_args="start-foreground"
command_background=true
pidfile="/var/run/zookeeper1.pid"
start_stop_daemon_args="--user zookeeper --group zookeeper"

depend() {
    need net
    use dns logger
}

赋予执行权限并启动：

sudo chmod +x /etc/init.d/zookeeper1
sudo service zookeeper1 start

zoo2启动脚本

创建/etc/init.d/zookeeper2：

#!/sbin/openrc-run
# Copyright 2023 Your Company Name
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

description="Zookeeper server 2"

command="/usr/bin/zkServer.sh"
command_args="start-foreground"
command_background=true
pidfile="/var/run/zookeeper2.pid"
start_stop_daemon_args="--user zookeeper --group zookeeper"

depend() {
    need net
    use dns logger
}

赋予执行权限并启动：

sudo chmod +x /etc/init.d/zookeeper2
sudo service zookeeper2 start

zoo3启动脚本

创建/etc/init.d/zookeeper3：

#!/sbin/openrc-run
# Copyright 2023 Your Company Name
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

description="Zookeeper server 3"

command="/usr/bin/zkServer.sh"
command_args="start-foreground"
command_background=true
pidfile="/var/run/zookeeper3.pid"
start_stop_daemon_args="--user zookeeper --group zookeeper"

depend() {
    need net
    use dns logger
}

赋予执行权限并启动：

sudo chmod +x /etc/init.d/zookeeper3
sudo service zookeeper3 start

4. 验证集群状态

你可以使用zkServer.sh status命令来验证每个Zookeeper实例的状态：

sudo /usr/bin/zkServer.sh status

你应该看到类似以下的输出：

ZooKeeper JMX enabled by default
Using config: /etc/zookeeper/conf/zoo1.cfg
Mode: leader

对于其他实例，模式应该是follower。

5. 配置防火墙

确保你的防火墙允许Zookeeper实例之间的通信。例如，使用ufw：

sudo ufw allow 2181/tcp
sudo ufw allow 2888/tcp
sudo ufw allow 3888/tcp

6. 监控和日志

配置监控和日志记录以确保集群的健康状态。你可以使用工具如Prometheus和Grafana来监控Zookeeper的性能指标。

通过以上步骤，你可以在Debian上实现Zookeeper的高可用性。