深入浅析Docker容器中的Patroni
上一篇文章向大家介绍了repmgr的搭建过程,实现了自动切换,今天将向大家介绍,如何搭建容器下的patroni集群环境,patroni作为开箱即用pg高可用工具,越来越多的被各个厂商用于云环境下使用。
patroni基本架构如图所示:
etcd作为分布式注册中心、进行集群选主工作;vip-manager为主节点设置漂移ip;patroni负责引导集群的创建、运行和管理工作,并可以使用patronictl来进行终端访问。
具体流程:
1、首先启动etcd集群,本例中etcd数量为3个。
2、检测etcd集群状态健康后,启动patroni并竞争选主,其他跟随节点进行数据同步过程。
3、启动vip-manager,通过访问etcd集群中/ s e r v i c e n a m e / {service_name}/ servicename/{cluster_name}/leader键中的具体值,判断当前节点是否为主节点ip,如果是则为该节点设置vip,提供对外读写服务。
注:建议真实环境下将etcd部署到独立容器上,对外提供服务。
创建镜像
文件结构
其中dockerfile为镜像主文件,docker服务通过该文件在本地仓库创建镜像;entrypoint.sh为容器入口文件,负责业务逻辑的处理;function为执行业务方法的入口文件,负责启动etcd,监控etcd集群状态、启动patroni和vip-manager;generatefile为整个容器生成对应的配置文件,包括etcd、patroni及vip-mananger。
目录结构大致如图所示:
注:数据库安装包和patroni安装包请自行构建。
dockerfile
from centos:7 maintainer wangzhibin <wangzhibin> env user="postgresql" \ password=123456 \ group=postgresql run useradd ${user} \ && chown -r ${user}:${group} /home/${user} \ && yum -y update && yum install -y iptables sudo net-tools iproute openssh-server openssh-clients which vim sudo crontabs #安装etcd copy etcd/etcd /usr/sbin copy etcd/etcdctl /usr/sbin #安装database copy lib/ /home/${user}/lib copy include/ /home/${user}/include copy share/ /home/${user}/share copy bin/ /home/${user}/bin/ copy patroni/ /home/${user}/patroni #安装vip-manager copy vip-manager/vip-manager /usr/sbin #安装执行脚本 copy runtime/ /home/${user}/runtime copy entrypoint.sh /sbin/entrypoint.sh #设置环境变量 env ld_library_path /home/${user}/lib env path /home/${user}/bin:$path env etcdctl_api=3 #安装patroni run yum -y install epel-release python-devel && yum -y install python-pip \ && pip install /home/${user}/patroni/1/pip-20.3.3.tar.gz \ && pip install /home/${user}/patroni/1/psycopg2-2.8.6-cp27-cp27mu-linux_x86_64.whl \ && pip install --no-index --find-links=/home/${user}/patroni/2/ -r /home/${user}/patroni/2/requirements.txt \ && pip install /home/${user}/patroni/3/patroni-2.0.1-py2-none-any.whl #修改执行权限 run chmod 755 /sbin/entrypoint.sh \ && mkdir /home/${user}/etcddata \ && chown -r ${user}:${group} /home/${user} \ && echo 'root:root123456' | chpasswd \ && chmod 755 /sbin/etcd \ && chmod 755 /sbin/etcdctl \ && chmod 755 /sbin/vip-manager #设置sudo run chmod 777 /etc/sudoers \ && sed -i '/## allow root to run any commands anywhere/a '${user}' all=(all) nopasswd:all' /etc/sudoers \ && chmod 440 /etc/sudoers #切换用户 user ${user} #切换工作目录 workdir /home/${user} #启动入口程序 cmd ["/bin/bash", "/sbin/entrypoint.sh"]
entrypoint.sh
#!/bin/bash set -e # shellcheck source=runtime/functions source "/home/${user}/runtime/function" configure_patroni
function
#!/bin/bash set -e source /home/${user}/runtime/env-defaults source /home/${user}/runtime/generatefile pg_datadir=/home/${user}/pgdata pg_bindir=/home/${user}/bin configure_patroni() { #生成配置文件 generate_etcd_conf generate_patroni_conf generate_vip_conf #启动etcd etcdcount=${etcd_count} count=0 ip_temp="" array=(${hostlist//,/ }) for host in ${array[@]} do ip_temp+="http://${host}:2380," done etcd --config-file=/home/${user}/etcd.yml >/home/${user}/etcddata/etcd.log 2>&1 & while [ $count -lt $etcdcount ] do line=(`etcdctl --endpoints=${ip_temp%?} endpoint health -w json`) count=`echo $line | awk -f"\"health\":true" '{print nf-1}'` echo "waiting etcd cluster" sleep 5 done #启动patroni patroni /home/${user}/postgresql.yml > /home/${user}/patroni/patroni.log 2>&1 & #启动vip-manager sudo vip-manager --config /home/${user}/vip.yml }
generatefile
#!/bin/bash set -e hostname="`hostname`" hostip=`ping ${hostname} -c 1 -w 1 | sed '1{s/[^(]*(//;s/).*//;q}'` #generate etcd generate_etcd_conf() { echo "name : ${hostname}" >> /home/${user}/etcd.yml echo "data-dir: /home/${user}/etcddata" >> /home/${user}/etcd.yml echo "listen-client-urls: http://0.0.0.0:2379" >> /home/${user}/etcd.yml echo "advertise-client-urls: http://${hostip}:2379" >> /home/${user}/etcd.yml echo "listen-peer-urls: http://0.0.0.0:2380" >> /home/${user}/etcd.yml echo "initial-advertise-peer-urls: http://${hostip}:2380" >> /home/${user}/etcd.yml ip_temp="initial-cluster: " array=(${hostlist//,/ }) for host in ${array[@]} do ip_temp+="${host}=http://${host}:2380," done echo ${ip_temp%?} >> /home/${user}/etcd.yml echo "initial-cluster-token: etcd-cluster-token" >> /home/${user}/etcd.yml echo "initial-cluster-state: new" >> /home/${user}/etcd.yml } #generate patroni generate_patroni_conf() { echo "scope: ${cluster_name}" >> /home/${user}/postgresql.yml echo "namespace: /${service_name}/ " >> /home/${user}/postgresql.yml echo "name: ${hostname} " >> /home/${user}/postgresql.yml echo "restapi: " >> /home/${user}/postgresql.yml echo " listen: ${hostip}:8008 " >> /home/${user}/postgresql.yml echo " connect_address: ${hostip}:8008 " >> /home/${user}/postgresql.yml echo "etcd: " >> /home/${user}/postgresql.yml echo " host: ${hostip}:2379 " >> /home/${user}/postgresql.yml echo " username: ${etcd_user} " >> /home/${user}/postgresql.yml echo " password: ${etcd_passwd} " >> /home/${user}/postgresql.yml echo "bootstrap: " >> /home/${user}/postgresql.yml echo " dcs: " >> /home/${user}/postgresql.yml echo " ttl: 30 " >> /home/${user}/postgresql.yml echo " loop_wait: 10 " >> /home/${user}/postgresql.yml echo " retry_timeout: 10 " >> /home/${user}/postgresql.yml echo " maximum_lag_on_failover: 1048576 " >> /home/${user}/postgresql.yml echo " postgresql: " >> /home/${user}/postgresql.yml echo " use_pg_rewind: true " >> /home/${user}/postgresql.yml echo " use_slots: true " >> /home/${user}/postgresql.yml echo " parameters: " >> /home/${user}/postgresql.yml echo " initdb: " >> /home/${user}/postgresql.yml echo " - encoding: utf8 " >> /home/${user}/postgresql.yml echo " - data-checksums " >> /home/${user}/postgresql.yml echo " pg_hba: " >> /home/${user}/postgresql.yml echo " - host replication ${user} 0.0.0.0/0 md5 " >> /home/${user}/postgresql.yml echo " - host all all 0.0.0.0/0 md5 " >> /home/${user}/postgresql.yml echo "postgresql: " >> /home/${user}/postgresql.yml echo " listen: 0.0.0.0:5432 " >> /home/${user}/postgresql.yml echo " connect_address: ${hostip}:5432 " >> /home/${user}/postgresql.yml echo " data_dir: ${pg_datadir} " >> /home/${user}/postgresql.yml echo " bin_dir: ${pg_bindir} " >> /home/${user}/postgresql.yml echo " pgpass: /tmp/pgpass " >> /home/${user}/postgresql.yml echo " authentication: " >> /home/${user}/postgresql.yml echo " replication: " >> /home/${user}/postgresql.yml echo " username: ${user} " >> /home/${user}/postgresql.yml echo " password: ${passwd} " >> /home/${user}/postgresql.yml echo " superuser: " >> /home/${user}/postgresql.yml echo " username: ${user} " >> /home/${user}/postgresql.yml echo " password: ${passwd} " >> /home/${user}/postgresql.yml echo " rewind: " >> /home/${user}/postgresql.yml echo " username: ${user} " >> /home/${user}/postgresql.yml echo " password: ${passwd} " >> /home/${user}/postgresql.yml echo " parameters: " >> /home/${user}/postgresql.yml echo " unix_socket_directories: '.' " >> /home/${user}/postgresql.yml echo " wal_level: hot_standby " >> /home/${user}/postgresql.yml echo " max_wal_senders: 10 " >> /home/${user}/postgresql.yml echo " max_replication_slots: 10 " >> /home/${user}/postgresql.yml echo "tags: " >> /home/${user}/postgresql.yml echo " nofailover: false " >> /home/${user}/postgresql.yml echo " noloadbalance: false " >> /home/${user}/postgresql.yml echo " clonefrom: false " >> /home/${user}/postgresql.yml echo " nosync: false " >> /home/${user}/postgresql.yml } #........ 省略部分内容
构建镜像
docker build -t patroni .
运行镜像
运行容器节点1:
docker run --privileged --name patroni1 -itd --hostname patroni1 --net my_net3 --restart always --env ‘cluster_name=patronicluster' --env ‘service_name=service' --env ‘etcd_user=etcduser' --env ‘etcd_passwd=etcdpasswd' --env ‘passwd=zalando' --env ‘hostlist=patroni1,patroni2,patroni3' --env ‘vip=172.22.1.88' --env ‘net_device=eth0' --env ‘etcd_count=3' patroni
运行容器节点2:
docker run --privileged --name patroni2 -itd --hostname patroni2 --net my_net3 --restart always --env ‘cluster_name=patronicluster' --env ‘service_name=service' --env ‘etcd_user=etcduser' --env ‘etcd_passwd=etcdpasswd' --env ‘passwd=zalando' --env ‘hostlist=patroni1,patroni2,patroni3' --env ‘vip=172.22.1.88' --env ‘net_device=eth0' --env ‘etcd_count=3' patroni
运行容器节点3:
docker run --privileged --name patroni3 -itd --hostname patroni3 --net my_net3 --restart always --env ‘cluster_name=patronicluster' --env ‘service_name=service' --env ‘etcd_user=etcduser' --env ‘etcd_passwd=etcdpasswd' --env ‘passwd=zalando' --env ‘hostlist=patroni1,patroni2,patroni3' --env ‘vip=172.22.1.88' --env ‘net_device=eth0' --env ‘etcd_count=3' patroni
总结
本操作过程仅限于试验环境,为了演示etcd+patroni+vipmanager整体的容器化搭建。在真实环境下,etcd应该部署在不同容器下,形成独立的分布式集群,并且pg的存储应该映射到本地磁盘或网络磁盘,另外容器集群的搭建尽量使用编排工具,例如docker-compose、docker-warm或者kubernetes等。
附图
etcd集群状态如图:
patroni集群状态如图:
vip-manager状态如图:
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