HAProxy re-enable server when is up again

haproxy

I'm trying to make sure that when a server goes up after being down (and not active any more) it will be re-enabled automatically.

This is my haproxy.cfg:

global
    log 127.0.0.1 local0
    log 127.0.0.1 local1 notice
    chroot /var/lib/haproxy
    user haproxy
    group haproxy
    # daemon

defaults
    log global
    mode tcp
    #retries 3
    option tcplog
    option dontlognull
    option redispatch
    no option persist
    #balance roundrobin
    balance leastconn
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms
    errorfile 400 /etc/haproxy/errors/400.http
    errorfile 403 /etc/haproxy/errors/403.http
    errorfile 408 /etc/haproxy/errors/408.http
    errorfile 500 /etc/haproxy/errors/500.http
    errorfile 502 /etc/haproxy/errors/502.http
    errorfile 503 /etc/haproxy/errors/503.http
    errorfile 504 /etc/haproxy/errors/504.http

listen stats 0.0.0.0:9000       #Listen on all IP's on port 9000
    mode http
    balance
    timeout client 5000
    timeout connect 4000
    timeout server 30000

    #This is the virtual URL to access the stats page
    stats uri /haproxy_stats

    #Authentication realm. This can be set to anything. Escape space characters with a backslash.
    stats realm HAProxy\ Statistics

    #The user/pass you want to use. Change this password!
    stats auth admin:adminpassword

    #This allows you to take down and bring up back end servers.
    #This will produce an error on older versions of HAProxy.
    stats admin if TRUE

# FRONTEND - NON-SSL
frontend www-http
    bind *:80
    # detect capacity issues in production farm
    acl MAIN_not_enough_capacity nbsrv(www-unsecure-backend-proxy) le 2
    # failover traffic to backup farm
    use_backend www-unsecure-backend-direct if MAIN_not_enough_capacity
    default_backend www-unsecure-backend-proxy

# BACKEND - NON-SSL
backend www-unsecure-backend-proxy
    mode tcp
    server rproxycache01 rpcache01.container:80 check
    server rproxycache02 rpcache02.container:80 check

# FALLBACK - NON-SSL
backend www-unsecure-backend-direct
    option allbackups
    server rproxycache01 rpcache01.container:80 check
    server rproxycache02 rpcache02.container:80 check
    server frontend01    web01.container:80 check backup
    server frontend02    web02.container:80 check backup

so, let's say all the servers are down, whenever one goes back up it should be used, but I've checked in the web interface and all the servers are red.

How can I do it?

Thank you in advance.

Best Answer

I'd say that global setting retries 3 is causing problems for you. After 3 retries, HAProxy will give up on further checks. See the documentation for retries directive.

Since you didn't set inter value, HAProxy will check server availability every 2 seconds. If your server was unavailable for more than 6 seconds, HAProxy will consider it permanently down.

I'd suggest that you comment out retries 3 line (or set bigger value) and/or adjust check inter value, restart HAProxy and redo the tests.

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