需求：编写脚本实现对redis cluster 主从是否发生主从切换进行监控，若发生切换，输出切换前后主从对应关系。
初始化对比文件,仅执行一次，后续不需要在执行，除非该文件不存在。
cmd="redis-cli -c -h $1 -p $2" $cmd cluster nodes > cluster_nodes.txt cat cluster_nodes.txt | awk -F[ @] '/master/{print $1,$2}' | sort -nk2 -t ':' > master.txt cat cluster_nodes.txt | awk -F[ @] '/slave/{print $2,$5}' | sort -nk1 -t ':' > slave.txt cat master.txt | while read m do master_ip_port=`echo $m | awk '{print $2}'` master_tag=`echo $m | awk '{print $1}'` cat slave.txt | while read s do slave_ip_port=`echo $s | awk '{print $1}'` slave_tag=`echo $s | awk '{print $2}'` if [[ ${master_tag} == ${slave_tag} ]];then echo "${master_ip_port}->${slave_ip_port}" >> master_slave_map_old fi done done
判断是否发生切换，如果发生，输出切换前后的对应关系
cmd="redis-cli -c -h $1 -p $2" $cmd cluster nodes > cluster_nodes.txt cat cluster_nodes.txt | awk -F[ @] '/master/{print $1,$2}' | sort -nk2 -t ':' > master.txt cat cluster_nodes.txt | awk -F[ @] '/slave/{print $2,$5}' | sort -nk1 -t ':' > slave.txt cat master.txt | while read m do master_ip_port=`echo $m | awk '{print $2}'` master_tag=`echo $m | awk '{print $1}'` cat slave.txt | while read s do slave_ip_port=`echo $s | awk '{print $1}'` slave_tag=`echo $s | awk '{print $2}'` if [[ ${master_tag} == ${slave_tag} ]];then echo "${master_ip_port}->${slave_ip_port}" >> master_slave_map_new fi done done ports=($($cmd cluster nodes | awk -F[ :@] '{print $3}' | sort |uniq)) len=${#ports[@]} for ((i=0;i<=$len-1;i++)) do old=$(grep ${ports[i]} master_slave_map_old | md5sum | awk '{print $1}') new=$(grep ${ports[i]} master_slave_map_new | md5sum | awk '{print $1}') if [[ "${old}" != "${new}" ]];then echo -n "${ports[i]}主从实例切换前：" grep ${ports[i]} master_slave_map_old echo -n "${ports[i]}主从实例切换后：" grep ${ports[i]} master_slave_map_new fi done cat master_slave_map_new > master_slave_map_old rm -rf master_slave_map_new
测试过程：
5.5.5.101:29001> info replication # Replication role:slave master_host:5.5.5.102 master_port:29001 master_link_status:up master_last_io_seconds_ago:0 master_sync_in_progress:0 slave_repl_offset:360775 slave_priority:100 slave_read_only:1 connected_slaves:0 master_replid:3c06fcc274b6fac6fe1d954f8b63687619e65cf5 master_replid2:0000000000000000000000000000000000000000 master_repl_offset:360775 second_repl_offset:-1 repl_backlog_active:1 repl_backlog_size:52428800 repl_backlog_first_byte_offset:1 repl_backlog_histlen:360775 lxd-vm1:29001> CLUSTER FAILOVER OK 5.5.5.101:29001> info replication # Replication role:master connected_slaves:1 slave0:ip=5.5.5.102,port=29001,state=online,offset=361741,lag=1 master_replid:a35374725759383211f8f76d6b9376d181beda17 master_replid2:3c06fcc274b6fac6fe1d954f8b63687619e65cf5 master_repl_offset:361755 second_repl_offset:360888 repl_backlog_active:1 repl_backlog_size:52428800 repl_backlog_first_byte_offset:1 repl_backlog_histlen:361755 lxd-vm1:29001>
测试结果
[redis@lxd-vm3 ~]$ sh a2.sh 5.5.5.101 29001 29001主从实例切换前：5.5.5.102:29001->5.5.5.101:29001 29001主从实例切换后：5.5.5.101:29001->5.5.5.102:29001 [redis@lxd-vm3 ~]$