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Questions[redis-sentinel](server)

Martin Hope
user2798081
Asked: 2021-12-15 00:17:31 +0800 CST
  • 0

I have set up three Redis servers using Bitnami Docker images. Both plain and TLS ports have been configured for Redis and Sentinel. How does Sentinel determine which Redis Master port (TLS or plain) should present to the client? Is there any configuration for this?

Environment: 3 x "Ubuntu 20.04 LTS" servers, Redis & Sentinel 6.2 containers installed on all servers.

redis bitnami redis-sentinel
Martin Hope
Konrad
Asked: 2021-06-30 00:01:22 +0800 CST
  • 1

I have dockerized images of redis (as official dockerhub guides when using custom redis.conf) and custom image (based on alpine image see here: https://pastebin.com/9WsMk1JC ) of sentinel (also with custom sentinel.conf).

In redis.conf, those three parameters was added (rest stays as default conf file):

masterauth password
masteruser default
requirepass password

In sentinel.conf, because of separation of redis instance (other containers) and sentinel is set up to boot up with non existing master on localhost. I've added parameters to perform auth on master. So config file have two additional parameters (rest stays as default conf file):

sentinel auth-pass mymaster password
sentinel auth-user mymaster default

After redis container is booted and ready for connections I start sentinel image, when it's done I connect to redis CLI on sentinel port and switch master by hand:

redis-cli -p 26379 sentinel remove mymaster && redis-cli -p 26379 sentinel monitor mymaster <redis container ip> 6379 2

sentinel's CLI returns OK two times but after a while it prints out that master is down. And it stays in this status forever.

Connectivity between containers tested via telnet and ping - OK.

My guess is that redis sentinel cannot connect to master - because of password.

Why?

  1. Replicas of redis container - making couple of image copies running and joining them in MASTER-SLAVE via CLI works like a charm. Containers can talk to each other using password from redis.conf.
  2. Before introducing passwords to redis contianers, sentinels could connect and perform successful failovers.
  3. Worked on Openshift without password setup.
docker redis redis-sentinel
Martin Hope
Gergely Lukacsy
Asked: 2016-06-23 07:50:31 +0800 CST
  • 1

I've set up four server and sentinel instances on four different virtual machines in a simple master-slave setup. The key replication works fine, and all redis nodes recognized each other (I'm referring to the known-sentinel and known-slave options).

The problem comes up when I'm trying to simulate a failure. The sentinels just keep telling that they can't elect a new master (failover-abort-not-elected):

12481:X 22 Jun 17:20:05.761 # <__IP1__>:51002 voted for a3ba8d8cd0c15c8b186b44ba529b83d3a8424a42 27
12481:X 22 Jun 17:20:14.140 # -sdown master mymaster <__IP2__> 6379
12481:X 22 Jun 17:20:14.140 # -odown master mymaster <__IP2__> 6379
12481:X 22 Jun 17:20:16.567 # -failover-abort-not-elected master mymaster <__IP2__> 6379

Another strange thing that when I query the sentinel's state in redis-cli, I keep getting greater values for the number of available sentinel instances than the actual count (which is of course, cannot be greater then 4 (right?)).

$ redis-cli -p 51001
> info
[...]
master0:name=mymaster,status=ok,address=91.120.59.231:6379,slaves=3,sentinels=8

Also, I keep getting these -dup-sentinel messages when starting up sentinel:

14563:X 23 Jun 11:10:18.015 * -dup-sentinel master mymaster <__IP_MASTER__> 6379 #duplicate of <__IP_SLAVE2__>:51003 or 65db9ddba84433f71aa77c9263807e6abd939d2c

Here's one of the sentinels' config:

daemonize yes
pidfile "/var/run/redis/redis-sentinel.pid"
logfile "/var/log/redis/redis-sentinel.log"

# bind 192.168.1.100 10.0.0.1
# port 26379

port 51004

dir "/var/lib/redis"

sentinel monitor mymaster <__IP_MASTER__> 6379 2
sentinel failover-timeout mymaster 60000
sentinel auth-pass mymaster <___________PASSW___________>
sentinel config-epoch mymaster 0
sentinel leader-epoch mymaster 55428

# Generated by CONFIG REWRITE
maxclients 4064
sentinel known-slave mymaster <__IP_SLAVE1__> 6379
sentinel known-slave mymaster <__IP_SLAVE2__> 6379
sentinel known-slave mymaster <__IP_SLAVE3__> 6379
sentinel known-sentinel mymaster <__IP_SLAVE1__> 51002 bfea8e89873353d5c1e9ed498b17f298bd6b6082
sentinel known-sentinel mymaster <__IP_MASTER__> 26379 c04fc07022a251e56e81e21dbe018bd471745038
sentinel known-sentinel mymaster <__IP_SLAVE2__> 51003 b5a56eb69abb5893203ecf7b1a7d28ae4aa06ab5
sentinel known-sentinel mymaster <__IP_MASTER__> 51001 be1ff6c9e4a62abea132c24447fd3cb38d221496
sentinel known-sentinel mymaster <__IP_SLAVE1__> 26379 f5a7fd0ee199afc02ffafc0e822363acf5595b1c
sentinel known-sentinel mymaster <__IP_SLAVE2__> 26379 6328962293b7838fa88b9f176b9bc4cc08f2e26d
sentinel current-epoch 26

The log files aren't really informative... is there a way to make it a little bit more verbose? Do you have any idea what am I misssing here?

Thanks in advance!

Bumping post:

Checked firewall settings, it should have been okay, I was still getting the same error when I shut off the firewall completley.

redis-sentinel
Martin Hope
chaintng
Asked: 2016-05-27 22:00:30 +0800 CST
  • 1

I tried to set up redis sentinel to make it has high availability and support fail over. I begin by setup the redis replication (1 master and 2 slaves in 3 ec2-instances)

And after that, i install redis-sentinel service for each instance.

However, when i tried to access redis-sentinal remotely (from my local machine) It shows following message

DENIED Redis is running in protected mode because protected mode is enabled, no bind address was specified, no authentication password is requested to clients....

So, i tried to set requirepass in sentinel.conf. But after i run redis-cli -h REDIS-IP -a PASSWORD -p SENTINEL_PORT INFO

It shows following

NOAUTH Authentication required.

Is there anyway i could connect to redis-sentinel remotely?

Please advise.

redis redis-sentinel