Redis Include features to _auto_ add and remove node from cluster on redis-trb or redis-cli (4.2)

As describe here to upgrade a node we have to perform a set of operations over each node and depend on node type that operations are different. It would be great to include a two simple operations like up and down. Despite the name the idea is to make transparent the process of delete or add a node.

To get something similar to this feature I have used the redis-trib.rb commands in a shell script:

slave-ip() {
    #slave0:ip=127.0.0.1,port=7003,state=online,offset=1695,lag=1
    return $(redis-cli -p $PORT info | grep slave0 | cut -d: -f2  | cut -d= -f2 | cut -d, -f1)
}

failover() {
    redis-cli -h $1 -p $PORT cluster failover
}

is-master() {
    ROLE=$(redis-cli role 2> /dev/null | grep master | wc -l)
    [ "${ROLE}" == "1" ] && return 0 || return 1
}

has-slave() {
    NO_SLAVE_LINES=$(redis-cli -p $PORT info | grep connected_slaves:0 | wc -l)
    [ "${NO_SLAVE_LINES}" == "1" ] && return 1 || return 0
}

rebalance (){
    redis-trib rebalance $@ --use-empty-masters $NODE_IP
}

delete-node () {
    if is-master ; then
        if has-slave ; then
            failover slave-ip
        else
            rebalance --weight $NODE_SHORT_ID=0.0
            redis-trib del-node $OTHER_MASTER_IP $NODE_ID
            rm $REDIS_CONF/$NODE_CONF_FILE
        fi
    fi
    exit 0
}

add-node () {
    if is-master ; then
        redis-trib add-node $NODE_IP $OTHER_MASTER_IP
        rebalance --weight $NODE_SHORT_ID=1.0
    else
        redis-trib add-node --slave $NODE_IP $OTHER_MASTER_IP
    fi
    exit 0
}

Comment From: thakurajayL

hi @jdvr , is this script part of codebase now ?

Thanks Ajay

Comment From: jdvr

No, this scripts is a helper for redis ansible role: https://github.com/idealista/redis-role

You can find it here