After sentinel failover. My slave prometed as a new master. But my old master couldn't convert as a slave. Sentinel's log is below getting forever :)
26378:X 23 May 17:55:00.429 * +convert-to-slave slave 10.0.22.43:6379 10.0.22.43 6379 # master01 10.0.22.44 6379
I tested this redis v3.2.0 and v3.0.7
same error. I am missing something.
Related
When I check my slaves
redis-cli -p 26379 sentinel slaves mycluster
I get some ips that have already been nuked.
Is there away to take them out of sentinel?
You can send SENTINEL RESET master command to every sentinel to remove these slaves.
I have a setup with 3 redis servers and 3 redis sentinels on each node.In the beginning we have one master node and two slave nodes, but after some time all the redis nodes went out of cluster and goes into slave mode.
I don't know why this is happening, am I missing something here?
Redis-Server configurations:
Redis-Server A (master node)
Redis-Server B (slaveof node A)
Redis-Server C (slaveof node A)
Redis-Sentinel Configuration for all three nodes are:
sentinel monitor Redis-Cluster ip-of-master-node 6379 2
sentinel down-after-milliseconds Redis-Cluster 2000
sentinel failover-timeout Redis-Cluster 2000
sentinel parallel-syncs Redis-Cluster 1
bind ip-of-interface
I'm testing redis failover with this simple setup:
3 Ubuntu server 16.04
redis and redis-sentinel are configured on each box.
Master ip : 192.168.0.18
Resque ip : 192.168.0.16
Resque2 ip : 192.168.0.13
Data replication works well but I can't get failover to work.
When I start redis-sentinel I always get a +sdown message after 60 seconds:
14913:X 17 Jul 10:40:03.505 # +monitor master mymaster 192.168.0.18 6379 quorum 2
14913:X 17 Jul 10:41:03.525 # +sdown master mymaster 192.168.0.18 6379
this is the configuration file for redis-sentinel:
bind 192.168.0.18
port 16379
sentinel monitor mymaster 192.168.0.18 6379 2
sentinel down-after-milliseconds mymaster 60000
sentinel failover-timeout mymaster 6000
loglevel verbose
logfile "/var/log/redis/sentinel.log"
repl-ping-slave-period 5
slave-serve-stale-data no
repl-backlog-size 8mb
min-slaves-to-write 1
min-slaves-max-lag 10
the bind directive uses the proper IP for each box.
I followed the redis tutorial here: https://redis.io/topics/sentinel but I can't get the failover to work.
Redis server version : 3.2.9
The issue is all about how redis-sentinel works because sentinel can not handle password protected redis-server.
In your redis-server configuration file (/etc/redis/redis.conf) do not use "requirepass" directive if you want to use redis-sentinel.
Hi i have create a cluster Redis with sentinel composed by 3 aws instances, i have configured sentinel to have an HA redis cluster and work, but if i simulate a crash of master (shutdown of master instance), sentinel installed on slaves, not locate sentinel of master and the election fail.
My sentinel configuration is:
sentinel monitor master ip-master 6379 2
sentinel down-after-milliseconds master 5000
sentinel failover-timeout master 10000
sentinel parallel-syncs master 1
Same file to all instaces
There are issues when running sentinel on the same node as the master and attempting to trigger a failover. Try it w/o running Sentinel on the master. Ultimately this means not running Sentinel on the same nodes as the Redis instances.
In your case your dead-node simulation is showing why you should not run Sentinel on the same node as Redis: If the node dies you lose one of your sentinels. In theory it should still work but as you and others have seen it isn't certain to work. I have some theories why but I've not yet confirmed them.
In a sense Sentinel is partly a monitoring system. Running a monitoring solution on the same nodes as are being monitored is generally unadvisable anyway, so you should be using off-node sentinels anyway. As Sentinel is resource efficient you don't necessarily need dedicated machines or large VMs. Indeed if you have a static set of application servers (where your client code runs), you should run Sentinel there, keeping in mind you want 3 minimum and a quorum of 50%+1.
recent redis version introduced the "protected-mode" option, which defaults to yes.
with protected-mode set to yes, redis instances, without a password set will not allow remote clients to execute commands.
this also affects sentinels master election.
try it with setting "protected-mode no" in the sentinels. this will allow them to talk to each other.
If you don't want to set protected-mode as no. you'd better set masterauth myredis in redis.conf and use sentinel auth-pass mymaster myredis in sentinel.conf
I am working with two redis instances monitored by one sentinel.
when the master goes down and there is a "+sdown", I run a notification-script where I promote the slave to master using the following command on its redis-client:
SLAVEOF NO ONE .
It works fine.
My question is, it takes around 10 secs for the slave to become master and the application to continue working again.
How can i reduce this time stamp?
below is the sentinel config::::
sentinel monitor mymaster 127.0.0.1 6379 1
sentinel down-after-milliseconds mymaster 5000
sentinel failover-timeout mymaster 900000
sentinel can-failover mymaster yes
sentinel parallel-syncs mymaster 1
sentinel notification-script mymaster /etc/init.d/config/script.sh
This is not a direct answer to your question, but a description of a different setup that avoids the need for having a quick response (in some scenario's).
When we model a use case in UML, we never put the redis sentinel in the default flow. The sentinel is our guard for situations where unknown errors occor: the exceptional flow.
If we know beforehand if the client needs to connect to a different redis instance, we simply instruct the client to do so, using redis pub/sub (combined with low resolution polling, since pub/sub traffic is not guaranteed-delivery).
Kind regards, TW
Try reduce sentinel down-after-milliseconds mymaster and failover-timeout mymaster