Differences between revisions 24 and 41 (spanning 17 versions)

Redis

Redis is an in memory data structure storage. It will be used to share PHP-sessions between the apache servers. To guarantee a robust deployment three redis servers will be configured.

192.168.1.59 redis01 (master)
192.168.1.60 redis02 (replica)
192.168.1.61 redis03 (replica)

Software

apt-get install redis-server redis-sentinel

Configuration

Redis Server

Change the contents of the redis configuration file in /etc/redis/redis.conf.

Add the IP-address for each of the servers. Each of the redis servers needs to listen on its own IP-address.

bind 192.168.1.59 127.0.0.1 ::1

Enable redis to listen on the network, instead of only listening on the loopback device.

protected-mode no

Now restart the redis master

service redis-server restart

And stop the replicas

service redis-server stop

On each of the replicas, set them up af a replica of the master

replicaof 192.168.1.59 6379

Start the replicas again

services redis-server start

You should now be able to see the replicas from the master redis-cli -h 192.168.1.59.

192.168.1.59:6379> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.1.60,port=6379,state=online,offset=2615,lag=0
slave1:ip=192.168.1.61,port=6379,state=online,offset=2615,lag=1
master_replid:79a21f08669303e71990ea8819830f30c94384c6
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:2615
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:2615

-  ⇤ ← Revision 24 as of 2021-01-02 01:39:31 → 
  Size: 2440
  Editor: Kristian Kallenberg
  Comment:
+   ← Revision 41 as of 2021-01-04 21:59:29 → ⇥
  Size: 2603
  Editor: Kristian Kallenberg
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
-DISCLAIMER
THIS ONLY WORKS IN BUSTER
INCOMPLETE DO NOT USE
-Line 9:
+Line 5:
- * 192.168.1.59 redis01
 * 192.168.1.60 redis02
 * 192.168.1.61 redis03
+ * 192.168.1.59 redis01 (master)
 * 192.168.1.60 redis02 (replica)
 * 192.168.1.61 redis03 (replica)
-Line 16:
+Line 12:
-apt-get install redis-server
+apt-get install redis-server redis-sentinel
-Line 27:
+Line 23:
-bind 127.0.0.1 192.168.1.58
+bind 192.168.1.59 127.0.0.1 ::1
-Line 29:
+Line 25:
-Line 36:
+Line 31:
-Redis stores its data in memory only, hence its speed. To make sure redis does not loose its state, in case of a hardware failure, this will enable it to store the state as it changes in a file on disk.
+Now restart the redis master
-Line 38:
+Line 33:
-appendonly yes
+service redis-server restart
-Line 41:
+Line 36:
-Activate redis cluster features
{{{
cluster-enabled yes
cluster-config-file nodes-6379.conf
cluster-node-timeout 15000
}}}

Stop redis on all hosts.
+And stop the replicas
-Line 53:
+Line 41:
-Remove `//var/lib/redis/nodes-6379.conf` as this file is identical on all nodes, and will cause each  node to have the same id
+On each of the replicas, set them up af a replica of the master
-Line 55:
+Line 43:
-rm /var/lib/redis/nodes-6379.conf
+replicaof 192.168.1.59 6379
-Line 58:
+Line 46:
-Start redis on all hosts.
+Start the replicas again
-Line 60:
+Line 48:
-service redis-server start
+services redis-server start
-Line 63:
+Line 51:
-Next we will need to configure the servers to run as a cluster
+You should now be able to see the replicas from the master `redis-cli -h 192.168.1.59`.
-Line 65:
+Line 53:
-redis-cli --cluster create 192.168.1.59:6379 192.168.1.60:6379 192.168.1.61:6379
+.168.1.59:6379> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.1.60,port=6379,state=online,offset=2615,lag=0
slave1:ip=192.168.1.61,port=6379,state=online,offset=2615,lag=1
master_replid:79a21f08669303e71990ea8819830f30c94384c6
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:2615
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:2615
-Line 80:
+Line 81:
+ * https://stackoverflow.com/questions/39568561/how-to-solve-redis-cluster-waiting-for-the-cluster-to-join-issue

Redis

Software

Configuration

Redis Server

References