1

I configured an HAProxy service for my Redis Cluster installation (3 nodes with Redis Sentinel managing the master delegation) and it works good: clients are redirected only to the master node and whenever a slave node becomes master, HAProxy suddenly change the active member into the backend.

Just wanting to be meticulous, the slave nodes are shown as "DOWN" (red colour) into the HAProxy Statistics Report (Layer7 timeout: at step 5 of tcp-check (expect string 'role:master')). Is there a way to have them shown as "backup UP" (blue colour), which is the correct definition?

This because red nodes seems to be a problem, but this is not true as slave members are UP but they are just slave so they are not active. I think this is the correct definition of the "backup UP" state into HAProxy.

This is the configuration of HAProxy:

frontend Redis bind 192.168.70.90:6379 name 192.168.70.90:6379 mode tcp log global timeout client 30000 default_backend Redis_tcp_ipvANY backend Redis_tcp_ipvANY mode tcp timeout connect 30000 timeout server 30000 retries 3 option tcp-check tcp-check connect tcp-check send PING\r\n tcp-check expect string +PONG tcp-check send info\ replication\r\n tcp-check expect string role:master tcp-check send QUIT\r\n tcp-check expect string +OK server redis1 192.168.70.91:6379 check inter 1000 maxconn 1024 server redis2 192.168.70.92:6379 check inter 1000 maxconn 1024 server redis3 192.168.70.93:6379 check inter 1000 maxconn 1024

Do you have any idea about how it's possible to do what I want?

Thanks!

Improve this question
4
  • Are you sure the health check for the backup node is coming back as up? Commented Nov 1, 2017 at 22:22
  • Yes, if I shutdown the master node one of the slave nodes becomes master and HAProxy makes it UP and green into the statistic page. Commented Nov 1, 2017 at 22:51
  • 3
    You have designed a health check that ensures that non-master nodes will fail the health check because tcp-check expect string role:master. Commented Nov 1, 2017 at 23:51
  • Yes, I understand this and I understand that HAProxy is working good. But I am wondering if there is any way to tell HAProxy to consider nodes which not have string role:master as BACKUP and not as DOWN. Commented Nov 2, 2017 at 9:32

1 Answer 1

Reset to default
2

It's possible, but as you have more than two nodes, IT WON'T FAIL OVER CORRECTLY. But since you asked:

backend Redis_tcp_ipvANY mode tcp timeout connect 30000 timeout server 30000 retries 3 option tcp-check tcp-check connect tcp-check send PING\r\n tcp-check expect string +PONG tcp-check send QUIT\r\n tcp-check expect string +OK server redis1 192.168.70.91:6379 inter 1000 maxconn 1024 check server redis2 192.168.70.92:6379 backup inter 1000 maxconn 1024 check server redis3 192.168.70.93:6379 backup inter 1000 maxconn 1024 check

The haproxy BACKUP state simply means the server won't be considered for load-balancing as long as any normal server is UP. Your present setup is better, I think.

Improve this answer
2
  • 1
    Why it will not failover correctly? Commented May 7, 2018 at 21:26
  • Because failover traffic will possibly go to backend that is not of role:master (there is one master, but you have two backups). Commented May 8, 2018 at 7:27

You must log in to answer this question.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.