Redis cluster setup with docker swarm

Redis Cluster Setup with Docker Swarm.md

Redis Cluster Setup with Docker Swarm

Setup

./redis.sh

Test

test the redis cluster

docker run -it --rm --net mynet redis:3.2.6 redis-cli -c -h redis -p 6379

10.0.0.7:6379> set mykey1 1
OK
10.0.0.7:6379> set mykey2 2
-> Redirected to slot [14119] located at 10.0.0.6:6379
OK
10.0.0.6:6379> set mykey3 3
-> Redirected to slot [9990] located at 10.0.0.4:6379
OK
10.0.0.4:6379> get mykey1
-> Redirected to slot [1860] located at 10.0.0.7:6379
"1"
10.0.0.7:6379> get mykey2
-> Redirected to slot [14119] located at 10.0.0.6:6379
"2"
10.0.0.6:6379> get mykey3
-> Redirected to slot [9990] located at 10.0.0.4:6379
"3"
10.0.0.4:6379> 

redis.sh

#!/bin/bash

REDIS_CONFIG='port 6379
cluster-enabled yes
cluster-config-file nodes.conf
cluster-node-timeout 5000
appendonly yes'

network=mynet

docker service create --name redis \
  --network $network \
  --replicas=6 \
  -e REDIS_CONFIG="$REDIS_CONFIG" \
  -e REDIS_CONFIG_FILE="/usr/local/etc/redis/redis.conf" \
  redis:3.2.6-alpine sh -c 'mkdir -p $(dirname $REDIS_CONFIG_FILE) && echo "$REDIS_CONFIG" > $REDIS_CONFIG_FILE && cat $REDIS_CONFIG_FILE && redis-server $REDIS_CONFIG_FILE'

sleep 2
docker service ps redis --no-trunc

# run the redis-trib.rb script  (the docker inspect runs on the host and the echo output is passed the along to the ruby container)
docker run -it --rm --net $network ruby sh -c "\
  gem install redis --version 3.2 \
  && wget http://download.redis.io/redis-stable/src/redis-trib.rb \
  && ruby redis-trib.rb create --replicas 1 \
  \$(getent hosts tasks.redis | awk '{print \$1 \":6379\"}') "

Note: the $network needs to be created with --attachable for the redis-trib.rb script to work.

what is network type ?? can i use overlay ??

it has to be overlay

what is the proper way to shutdown and reboot the docker nodes and actually have the redis cluster come back up.
Running two swarm nodes with 6 resdis instances on each.
Seems like everything I've tried results in a broken cluster.

2019-10-16 04:06:47 (348 MB/s) - 'redis-trib.rb' saved [3600/3600]

WARNING: redis-trib.rb is not longer available!
You should use redis-cli instead.

All commands and features belonging to redis-trib.rb have been moved
to redis-cli.
In order to use them you should call redis-cli with the --cluster
option followed by the subcommand name, arguments and options.

Use the following syntax:
redis-cli --cluster SUBCOMMAND [ARGUMENTS] [OPTIONS]

Example:
redis-cli --cluster create 10.0.26.20:6379 10.0.26.21:6379 10.0.26.24:6379 10.0.26.23:6379 10.0.26.19:6379 10.0.26.22:6379 --cluster-replicas 1

To get help about all subcommands, type:
redis-cli --cluster help