valkey/sentinel.conf

# Example sentinel.conf

# port <sentinel-port>
# The port that this sentinel instance will run on
port 26379

# sentinel monitor <master-name> <ip> <redis-port> <quorum>
#
# Tells Sentinel to monitor this slave, and to consider it in O_DOWN
# (Objectively Down) state only if at least <quorum> sentinels agree.
#
# Note: master name should not include special characters or spaces.
# The valid charset is A-z 0-9 and the three characters ".-_".
sentinel monitor mymaster 127.0.0.1 6379 2

# sentinel down-after-milliseconds <master-name> <milliseconds>
#
# Number of milliseconds the master (or any attached slave or sentinel) should
# be unreachable (as in, not acceptable reply to PING, continuously, for the
# specified period) in order to consider it in S_DOWN state (Subjectively
# Down).
#
# Default is 30 seconds.
sentinel down-after-milliseconds mymaster 30000

# sentinel can-failover <master-name> <yes|no>
#
# Specify if this Sentinel can start the failover for this master.
sentinel can-failover mymaster yes

# sentinel parallel-syncs <master-name> <numslaves>
#
# How many slaves we can reconfigure to point to the new slave simultaneously
# during the failover. Use a low number if you use the slaves to serve query
# to avoid that all the slaves will be unreachable at about the same
# time while performing the synchronization with the master.
sentinel parallel-syncs mymaster 1

# sentinel failover-timeout <master-name> <milliseconds>
#
# Specifies the failover timeout in milliseconds. When this time has elapsed
# without any progress in the failover process, it is considered concluded by
# the sentinel even if not all the attached slaves were correctly configured
# to replicate with the new master (however a "best effort" SLAVEOF command
# is sent to all the slaves before).
#
# Also when 25% of this time has elapsed without any advancement, and there
# is a leader switch (the sentinel did not started the failover but is now
# elected as leader), the sentinel will continue the failover doing a
# "takeover".
#
# Default is 15 minutes.
sentinel failover-timeout mymaster 900000

# SCRIPTS EXECTION
#
# sentinel notification-script and sentinel reconfig-script are used in order
# to configure scripts that are called to notify the system administrator
# or to reconfigure clients after a failover. The scripts are executed
# with the following rules for error handling:
#
# If script exists with "1" the execution is retried later (up to a maximum
# number of times currently set to 10).
#
# If script exists with "2" (or an higher value) the script execution is
# not retried.
#
# If script terminates because it receives a signal the behavior is the same
# as exit code 1.
#
# A script has a maximum running time of 60 seconds. After this limit is
# reached the script is terminated with a SIGKILL and the execution retried.

# NOTIFICATION SCRIPT
#
# sentinel notification-script <master-name> <script-path>
# 
# Call the specified notification script for any sentienl event that is
# generated in the WARNING level (for instance -sdown, -odown, and so forth).
# This script should notify the system administrator via email, SMS, or any
# other messaging system, that there is something wrong with the monitored
# Redis systems.
#
# The script is called with just two arguments: the first is the event type
# and the second the event description.
#
# The script must exist and be executable in order for sentinel to start if
# this option is provided.
#
# Example:
#
# sentinel notification-script mymaster /var/redis/notify.sh

# CLIENTS RECONFIGURATION SCRIPT
#
# sentinel client-reconfig-script <master-name> <script-path>
#
# When the failover starts, ends, or is aborted, a script can be called in
# order to perform application-specific tasks to notify the clients that the
# configuration has changed and the master is at a different address.
# 
# The script is called in the following cases:
#
# Failover started (a slave is already promoted)
# Failover finished (all the additional slaves already reconfigured)
# Failover aborted (in that case the script was previously called when the
#                   failover started, and now gets called again with swapped
#                   addresses).
#
# The following arguments are passed to the script:
#
# <master-name> <role> <state> <from-ip> <from-port> <to-ip> <to-port>
#
# <state> is "start", "end" or "abort"
# <role> is either "leader" or "observer"
# 
# The arguments from-ip, from-port, to-ip, to-port are used to communicate
# the old address of the master and the new address of the elected slave
# (now a master) in the case state is "start" or "end".
#
# For abort instead the "from" is the address of the promoted slave and
# "to" is the address of the original master address, since the failover
# was aborted.
#
# This script should be resistant to multiple invocations.
#
# Example:
#
# sentinel client-reconfig-script mymaster /var/redis/reconfig.sh