This is not just HA. This is sharding. And to avoid the need for specific libraries and code tweaks to talk to the cluster, you can otherwise enable redis-cluster-proxy once this is in place.
Note you need to setup the cluster BEFORE you start writing in the databases.
see redis-server
on every node
cd /etc/redis/
mv -i redis.conf redis.conf.dist
grep -vE '^[[:space:]]*#|^[[:space:]]*$' redis.conf.dist > redis.conf.clean
grep -vE '^[[:space:]]*#|^[[:space:]]*$' redis.conf.dist > redis.conf
vi redis.conf
bind 0.0.0.0
cluster-enabled yes
cluster-config-file nodes.conf
#cluster-node-timeout 5000
#appendonly yes
# default acl user
#requirepass SOME-PASSWORD
systemctl restart redis-server
systemctl status redis-server
systemctl enable redis-server
now that the daemon is up and running on every node, let’s define the cluster memberships
configure the master nodes — not sure why, but we have to use IP addresses here
redis-cli --cluster create 10.3.3.11:6379 10.3.3.12:6379 10.3.3.13:6379 # -a PASSWORD redis-cli cluster nodes # -a PASSWORD redis-cli --cluster check redis1:6379 # -a PASSWORD
add a slave to every master (here only the master node has to be ab IP)
redis-cli --cluster add-node redis5:6379 10.3.3.11:6379 \
--cluster-slave --cluster-master-id 93724406643ce2833b6f118aa17e1467f5cf9f40
redis-cli --cluster add-node redis6:6379 10.3.3.12:6379 \
--cluster-slave --cluster-master-id 83bacda2bc91020d2c0ea5101e6a9f640ce88a0c
redis-cli --cluster add-node redis4:6379 10.3.3.13:6379 \
--cluster-slave --cluster-master-id 1f77b40916a407845bbfb36ec9b22dec7e19aa56
available databases
redis-cli -h redis1 info | grep ^db # -a PASSWORD # | sed -rn '/^# Keyspace/,$p'
create key/value pairs that go to different shards on db0 e.g.
redis-cli -h redis1 set ref pouet set ref2 pouet2 set ref3 pouet3 keys * get ref get ref2 get ref3
re-distribute the shards
redis-cli --cluster fix redis1:6379
redis-cli --cluster del-node redisX:6379 NODE-ID
once a new master/slave pair is added to the cluster, redistribute the shards as such
redis-cli --cluster reshard redisX:6379
in case you want to serve on different ports
port 6380 cluster-config-file nodes-6380.conf pidfile /var/run/redis/redis-server-6380.pid logfile /var/log/redis/redis-server-6380.log dir /var/lib/redis-6380 vi ...SYSD UNIT... systemctl daemon-reload systemctl list-unit-files | grep redis systemctl restart redis-server-6380.service systemctl status redis-server-6380.service systemctl enable redis-server-6380.service
[ERR] Not all 16384 slots are covered by nodes.
==> --cluster fix NODE-ID
WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128. WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
==> see Install
Scaling with Redis Cluster https://redis.io/docs/manual/scaling/
CLUSTER NODES https://redis.io/commands/cluster-nodes
Redis Cluster https://redis.io/presentation/Redis_Cluster.pdf
https://www.linode.com/docs/guides/how-to-install-and-configure-a-redis-cluster-on-ubuntu-1604/