To implement encrypted communication between Redis masters and slaves, we recommend using stunnel. Stunnel works as TLS encryption wrapper between client and server.
This step-by-step tutorial will explain how to install and configure stunnel proxies on FreeBSD client and server. Configuration procedures for other operating systems are very similar. For simplicity, this tutorial only covers replication to one client host as this configuration does not require individual preshared keys for each of the clients.
Assuming we have 3 Redis instances on both server and client, listening sockets on the server (master side):
| instance | Redis socket | stunnel socket |
|---|---|---|
redis |
localhost:6379 | - |
bayes |
localhost:6378 | master.example.com:6478 |
fuzzy |
localhost:6377 | master.example.com:6477 |
As the instance named redis should not be mirrored, we will replicate fuzzy and bayes instances. So we need to setup 2 TLS tunnels.
First install the security/stunnel package:
# pkg install stunnel
Create pid-file directory:
# mkdir /var/run/stunnel && chown stunnel:stunnel /var/run/stunnel
To enable stunnel add the following lines to the /etc/rc.conf:
stunnel_enable="YES"
stunnel_pidfile="/var/run/stunnel/stunnel.pid"
/usr/local/etc/stunnel/stunnel.conf:
setuid = stunnel
setgid = nogroup
pid = /var/run/stunnel/stunnel.pid
[bayes]
accept = 6478
connect = 6378
ciphers = PSK
PSKsecrets = /usr/local/etc/stunnel/psk.txt
[fuzzy]
accept = 6477
connect = 6377
ciphers = PSK
PSKsecrets = /usr/local/etc/stunnel/psk.txt
/usr/local/etc/stunnel/stunnel.conf:
setuid = stunnel
setgid = nogroup
pid = /var/run/stunnel/stunnel.pid
[bayes]
client = yes
accept = localhost:6478
connect = master.example.com:6478
ciphers = PSK
PSKsecrets = /usr/local/etc/stunnel/psk.txt
[fuzzy]
client = yes
accept = localhost:6477
connect = master.example.com:6477
ciphers = PSK
PSKsecrets = /usr/local/etc/stunnel/psk.txt
Create /usr/local/etc/stunnel/psk.txt .
The psk.txt file contains one line for each client:
test1:oaP4EishaeSaishei6rio6xeeph3az
Do not use example passwords.
As both bayes and fuzzy Redis instances located at the same host we can share the same key between them.
Since this file should be kept secret set secure permissions on it:
# chmod 600 /usr/local/etc/stunnel/psk.txt
# service stunnel start
From the client host use the redis-cli utility to connect to the remote instances:
# redis-cli -p 6477
# redis-cli -p 6478
Given that it connected, you are clear to proceed with configuring replication between Redis instances.