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Redis Sentinel 启动脚本

2016年2月18日 发表评论 阅读评论 1,050 人阅读    

公司项目中使用到了 Redis Sentinel。以前只用过 Reids。所以，也只了解 Redis 的关闭和启动。至于 Redis Sentinel，那就抓瞎了。每次使用，都是先用现查，特别麻烦。这次在查资料时，在 Github Gist 上查到一个非常不错的启动脚本，可以非常方便地解决这个问题。分享给大家，希望对大家有所帮助。另外， 推荐大家认真阅读一下 Redis Sentinel 相关的文档。 废话完毕，上脚本：

查看源代码
打印帮助
01#!/bin/bash
02#
03# Starts redis sentinel using start-stop-daemon
04#
05# D瓜哥，http://www.diguage.com/
06#
07# 2016-02-17
08 
09NAME=redis-sentinel
10BIN=/usr/local/bin/redis-server # --1--
11CONF=/usr/local/etc/sentinel.conf
12SENTINEL_PID=/tmp/redis-sentinel.pid
13CMD=$1
14 
15start() {
16   echo "Starting $NAME ..."
17   # exec 2>&1 $BIN $CONF --sentinel | logger -t sentinel & # --2--
18   exec 2>&1 $BIN $CONF --sentinel &>/dev/null &
19   echo $! > "${SENTINEL_PID}";
20}
21 
22stop() {
23   PID=`cat $SENTINEL_PID`
24   echo "Stopping $NAME ($PID) ..."
25   kill $PID
26}
27 
28restart() {
29   echo "Restarting $NAME ..."
30   stop
31   start
32}
33 
34case "$CMD" in
35   start)
36     start
37     ;;
38   stop)
39     stop
40     ;;
41   restart)
42     restart
43     ;;
44   *)
45     echo "Usage $0 {start|stop|restart}"
46esac
  1. 使用时，请根据实际情况来修改相关命令以及参数的位置。
  2. 参考的源代码中使用的使用的是这种方式。但是，这种方式在 Mac 下，记录的 PID 是 logger 命令的 PID，导致的问题时，执行关闭命令时，不能正常的杀掉 Redis Sentinel 进程。这个问题，还需要再看看有没有更好的解决方案。

这里有几点东西需要说明一下，

  • 启动时，加入了参数 &>/dev/null，导致的结果是所有的日志都直接抛掉了。不方便追查日志。

  • 在 Mac 使用 Homebrew 安装完 Reids 后，D瓜哥没有找到关于 Redis Sentinel 的相关配置。这
    里给大家提供一个模板。如下：

查看源代码
打印帮助
001# port <sentinel-port>
002# The port that this sentinel instance will run on
003port 26379
004 
005# sentinel announce-ip <ip>
006# sentinel announce-port <port>
007#
008# The above two configuration directives are useful in environments where,
009# because of NAT, Sentinel is reachable from outside via a non-local address.
010#
011# When announce-ip is provided, the Sentinel will claim the specified IP address
012# in HELLO messages used to gossip its presence, instead of auto-detecting the
013# local address as it usually does.
014#
015# Similarly when announce-port is provided and is valid and non-zero, Sentinel
016# will announce the specified TCP port.
017#
018# The two options don't need to be used together, if only announce-ip is
019# provided, the Sentinel will announce the specified IP and the server port
020# as specified by the "port" option. If only announce-port is provided, the
021# Sentinel will announce the auto-detected local IP and the specified port.
022#
023# Example:
024#
025# sentinel announce-ip 1.2.3.4
026 
027# dir <working-directory>
028# Every long running process should have a well-defined working directory.
029# For Redis Sentinel to chdir to /tmp at startup is the simplest thing
030# for the process to don't interfere with administrative tasks such as
031# unmounting filesystems.
032dir /tmp
033 
034# sentinel monitor <master-name> <ip> <redis-port> <quorum>
035#
036# Tells Sentinel to monitor this master, and to consider it in O_DOWN
037# (Objectively Down) state only if at least <quorum> sentinels agree.
038#
039# Note that whatever is the ODOWN quorum, a Sentinel will require to
040# be elected by the majority of the known Sentinels in order to
041# start a failover, so no failover can be performed in minority.
042#
043# Slaves are auto-discovered, so you don't need to specify slaves in
044# any way. Sentinel itself will rewrite this configuration file adding
045# the slaves using additional configuration options.
046# Also note that the configuration file is rewritten when a
047# slave is promoted to master.
048#
049# Note: master name should not include special characters or spaces.
050# The valid charset is A-z 0-9 and the three characters ".-_".
051sentinel monitor mymaster 127.0.0.1 6379 2
052 
053# sentinel auth-pass <master-name> <password>
054#
055# Set the password to use to authenticate with the master and slaves.
056# Useful if there is a password set in the Redis instances to monitor.
057#
058# Note that the master password is also used for slaves, so it is not
059# possible to set a different password in masters and slaves instances
060# if you want to be able to monitor these instances with Sentinel.
061#
062# However you can have Redis instances without the authentication enabled
063# mixed with Redis instances requiring the authentication (as long as the
064# password set is the same for all the instances requiring the password) as
065# the AUTH command will have no effect in Redis instances with authentication
066# switched off.
067#
068# Example:
069#
070# sentinel auth-pass mymaster MySUPER--secret-0123passw0rd
071 
072# sentinel down-after-milliseconds <master-name> <milliseconds>
073#
074# Number of milliseconds the master (or any attached slave or sentinel) should
075# be unreachable (as in, not acceptable reply to PING, continuously, for the
076# specified period) in order to consider it in S_DOWN state (Subjectively
077# Down).
078#
079# Default is 30 seconds.
080sentinel down-after-milliseconds mymaster 30000
081 
082# sentinel parallel-syncs <master-name> <numslaves>
083#
084# How many slaves we can reconfigure to point to the new slave simultaneously
085# during the failover. Use a low number if you use the slaves to serve query
086# to avoid that all the slaves will be unreachable at about the same
087# time while performing the synchronization with the master.
088sentinel parallel-syncs mymaster 1
089 
090# sentinel failover-timeout <master-name> <milliseconds>
091#
092# Specifies the failover timeout in milliseconds. It is used in many ways:
093#
094# - The time needed to re-start a failover after a previous failover was
095#   already tried against the same master by a given Sentinel, is two
096#   times the failover timeout.
097#
098# - The time needed for a slave replicating to a wrong master according
099#   to a Sentinel current configuration, to be forced to replicate
100#   with the right master, is exactly the failover timeout (counting since
101#   the moment a Sentinel detected the misconfiguration).
102#
103# - The time needed to cancel a failover that is already in progress but
104#   did not produced any configuration change (SLAVEOF NO ONE yet not
105#   acknowledged by the promoted slave).
106#
107# - The maximum time a failover in progress waits for all the slaves to be
108#   reconfigured as slaves of the new master. However even after this time
109#   the slaves will be reconfigured by the Sentinels anyway, but not with
110#   the exact parallel-syncs progression as specified.
111#
112# Default is 3 minutes.
113sentinel failover-timeout mymaster 180000
114 
115# SCRIPTS EXECUTION
116#
117# sentinel notification-script and sentinel reconfig-script are used in order
118# to configure scripts that are called to notify the system administrator
119# or to reconfigure clients after a failover. The scripts are executed
120# with the following rules for error handling:
121#
122# If script exits with "1" the execution is retried later (up to a maximum
123# number of times currently set to 10).
124#
125# If script exits with "2" (or an higher value) the script execution is
126# not retried.
127#
128# If script terminates because it receives a signal the behavior is the same
129# as exit code 1.
130#
131# A script has a maximum running time of 60 seconds. After this limit is
132# reached the script is terminated with a SIGKILL and the execution retried.
133 
134# NOTIFICATION SCRIPT
135#
136# sentinel notification-script <master-name> <script-path>
137#
138# Call the specified notification script for any sentinel event that is
139# generated in the WARNING level (for instance -sdown, -odown, and so forth).
140# This script should notify the system administrator via email, SMS, or any
141# other messaging system, that there is something wrong with the monitored
142# Redis systems.
143#
144# The script is called with just two arguments: the first is the event type
145# and the second the event description.
146#
147# The script must exist and be executable in order for sentinel to start if
148# this option is provided.
149#
150# Example:
151#
152# sentinel notification-script mymaster /var/redis/notify.sh
153 
154# CLIENTS RECONFIGURATION SCRIPT
155#
156# sentinel client-reconfig-script <master-name> <script-path>
157#
158# When the master changed because of a failover a script can be called in
159# order to perform application-specific tasks to notify the clients that the
160# configuration has changed and the master is at a different address.
161#
162# The following arguments are passed to the script:
163#
164# <master-name> <role> <state> <from-ip> <from-port> <to-ip> <to-port>
165#
166# <state> is currently always "failover"
167# <role> is either "leader" or "observer"
168#
169# The arguments from-ip, from-port, to-ip, to-port are used to communicate
170# the old address of the master and the new address of the elected slave
171# (now a master).
172#
173# This script should be resistant to multiple invocations.
174#
175# Example:
176#
177# sentinel client-reconfig-script mymaster /var/redis/reconfig.sh

参考资料

  1. redis sentinel startup script

  2. Redis Sentinel Documentation – Redis



作 者： D瓜哥，https://www.diguage.com/
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