Is there any merit in setting up 2 nodes for Opscenter with its own storage on a virtual environment?
I am thinking 1 node is good but for H/A does having a second node help?
Thanks,
Vik
OpsCenter supports automatic failover in an active/passive configuration, but does not support an active/active configuration today. You can read more about this functionality and how to best shared OpsCenter settings storage between the two instances: http://docs.datastax.com/en/opscenter/5.2/opsc/configure/configFailover.html
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Can anyone explain to me what is aware client in Redis Enterprise ?
I found this post: Redis Enterprise Clustering Command Error 'CLUSTER'
I try to use Redis Enterprise Cluster with docker.
I create 3 docker redis nodes with two shards for better scalability.
So what exactly is that aware client and what is the difference between non-cluster aware ?
Also, what is regular OSS cluster ?
Thank You..
"Cluster Aware" means a Redis client that supports the OSS Cluster API (https://redis.io/topics/cluster-spec). For example, the Ruby client https://github.com/redis/redis-rb#cluster-support supports it.
A non-aware client is a client that only supports connecting to Redis in single-instance mode (and perhaps Sentinel), such as the Python client https://github.com/andymccurdy/redis-py.
The Enterprise Cluster can be used by both types of clients regardless of how the database is deployed (i.e. clustered or not).
To clear some more of the confusion:
OSS Cluster - a mode of deployment and API (i.e. not single-instance)
Enterprise Cluster - a product
We have 2 app/web servers running HA application, we need to setup redis with high availability/replication to support our app.
Considering the minimum sentinel setup requirement of 3 nodes.
We are planning to prepare the first app serve with redis master and 1 sentinel, the second app server will have the redis slave and 1 sentinel, we plan to add one additional server to hold the third sentinel node to achieve the 2 quorum sentinel setup.
Is this a valid setup ? what could be the risks ?
Thanks ,,,
Well it looks its not recommended to put the redis nodes on the app servers (where it is recommended to put the sentinel nodes there).
We ended with a setup for KeyDB (a fork from Redis) which claimed to be faster and support high availability/replication (and much more) to create two nodes within the app servers.
Of course We had to modify little in the client side to support some advance Lua scripts (There is some binary serialized data not getting replicated to the other node).
But after some effort, it worked ! as expected.
Hope this helps ...
Currently hazelcast is using cloud discovery for communication.
So if there are 4 kubernetes pods and each of them is having in-memory hazelcast. whenever hazelcast cache is updated in one of the pod, it gets updated in one of the other pod. but in case both of these pods get downscaled and get terminated, the data which is only in these 2 pods is lost. Can we have something like redis where we can provide server, port of the hazelcast cluster and it will be independent of kubernetes pod
Please check the following Blog Post ("Scale without Data Loss!" section) to read how to scale Hazelcast cluster on Kubernetes to avoid data loss.
Also, you can check the official README of hazelcast/hazelcast-kubernetes plugin. There is a section dedicated to scaling there.
I try to use redis for http session data replication. My Use case is as follows:
We have 2 indepentent datacenters(RZ and RR) each of them has 4 tomcat servers.
I have installed redis cluster with sentinel (One Master, 2 slaves and 3 sentinels)on one dedicated server on each datacenter. Each cluster is working as expected.
Now I want to synchrinze data between the 2 Masters nodes (cross-datacenter replication), so if our loadbalancer decide to shwitch from DC RZ(Primary) to DC RR (secondary) session data is available and no session is lost.
I tried to install dynomite framework formy purpose but failling to install it. So My question can redis handle such senario without third party tools such dynomite?
Any Help to achieve the replication between datacenter is very willcome.
Sorry for my bad english.
Thank you in Advance.
No, Redis does not offer master-master solution. See redis replication and cluster tutorial to understand how redis replication works
https://redis.io/topics/replication
https://redis.io/topics/cluster-tutorial
Dynomite is brilliant active-active solution, we have been using it for quite sometime.
No, there is no normal way to do this.
The Spring XD documentation (http://docs.spring.io/spring-xd/docs/1.0.0.RC1/reference/html/) recommends Zookeeper to be run in ensemble so that Zookeeper is highly available. There is not lot of details about Redis about high availability.
If I were to run 2 XD admin instances and say 4 Container instances, I see 3 options
should I run a Redis instance in each server that runs container or admin? In that case does the Distributed runtime work properly with different Redis instances handling transport of different modules?
OR
should I run 1 Redis instance in a separate server and configure all XD instances to talk to this instance? In this case 1 instance of Redis is not highly available
OR
should I configure Redis cluster or Redis Sentinel high availability? I am not sure how XD or any other client will connect to a cluster or HA.
Thanks
I would suggest that you run a single Redis instance, there are some settings for persistence that you can change that may meet your requirements.
http://redis.io/topics/persistence
We will be adding support for Redis Sentinal, certainly in the Spring XD 1.1 release, but possibly in a maintenance release depending on what library changes we need to pick up. Spring Data Redis and Spring Boot have recent updates to support Redis Sentinal.
If you are using Redis as a message transport and want higher guarantees, I would switch to using Rabbit HA configuration of the MessageBus.
Cheers,
Mark