redis-trib | Redis cluster tool script of redis-trib in golang | Command Line Interface library

The problem is, that you are passing fun et. al. to the runner instead of the execution module. Also note that you have to pass the arguments via arg and not args:

Ok so I figured it out. I needed to

1. set my cluster-announce-ip to the Ethernet adapter that has been created when installing docker (open up a terminal and do ipconfig)
2. update redis-trib.rb to reflect this IP
3. map the 16379 port when the docker image is created

Try:

When connecting to a cluster, ioredis will ask the :7000 for the node list of the cluster, and after that ioredis is able to discover the new node and handle the failover. So, the answer is yes if the :7000 dies after the node list being fetched.

AFAIK no - hash slots' "fragmentation" is negligible in terms of any meaningful overheads. Some intuition:

• Small range (16K)
• Resharding isn't a frequent operation
• Internally, Redis uses bitmaps to manage the slot mapping, so regardless of the actual slots' distribution accessing these bitmaps is done in constant time.

As you said that you're using 3 master nodes within Redis Cluster, so it is clearly visible that if one of node will down then you'll get CLUSTERDOWN errors.

To avoid these type of errors and get high availability, its better to have slaves attached to those of your master nodes(as shown in official Redis Cluster tutorial here).

There's a reason to have slave attached with your master to get higher availability. For that you can read these lines mentioned in above Redis cluster tutorial link.

There are 16384 hash slots in Redis Cluster, and to compute what is the hash slot of a given key, we simply take the CRC16 of the key modulo 16384.

Every node in a Redis Cluster is responsible for a subset of the hash slots, so for example you have a cluster with 3 nodes, where:

1) Node A contains hash slots from 0 to 5500.

2) Node B contains hash slots from 5501 to 11000.

3) Node C contains hash slots from 11001 to 16383.

So whenever you used to SET a Key in Redis cluster, it calculates its hash slot value for that key and save key accordingly in one of node. This is the reason it is mandatory to have all of nodes(At least master or its one slave) to be active in Redis Cluster.

Rest if you'll attach at least 1 slave with every master node into your Redis Cluster, you'll get better Redis Cluster availability. After attaching slaves with your master node, you can test your setup for higher availability by closing any of master node manually.

I think the programmer was having a bit of fun with that name and meant it to mean Redistribute.

From the page https://redis.io/topics/cluster-tutorial

... the Redis Cluster command line utility called redis-trib, a Ruby program executing special commands on instances in order to create new clusters, check or reshard an existing cluster, and so forth.

Since a cluster is sometimes called "distributed computing", the program deals entirely with cluster creation and maintenance, and there is no formal explanation of the name; I believe this to be what the programmer was trying to hint at.