Re: Help regarding mod_proxy_balancer, failover and failonstatus

[Daniel Ruggeri <DRuggeri@xxxxxxxxxxx>]

On 6/18/2012 3:17 PM, Praveen Baratam wrote:

Can mod_proxy failover with out ever returning an error to the client? If active node fails I need mod_proxy to try the Standby for the same request and not just from the subsequent request!

In our setup we are using mod_proxy_balancer to manage failover of backend servers. Backend servers may return an error code instead of timing out when some service such as NFS fails and we want such servers also to be marked as failed nodes. Hence we are using failonstatus directive for the balancer.

<Proxy balancer://failover>
    ProxySet failonstatus=503 
    BalancerMember http://active/ retry=30
    # the hot standby
    BalancerMember http://standby/ status=+H retry=0
</Proxy>

RewriteBase /
RewriteRule ^(.*)$ balancer://failover/$1 [P,L]

Currently the failover works perfectly with one glitch. When active node fails the user gets a 503 error and from the next request the Standby server takes over.

I dont want even a single request to fail though. 

Can this be achieved?

Thank you!

Praveen;
   I'm afraid there are no provisions available to retry a request to another backend server once it has been sent to a balancer member. I would like to fix this some day but I am just not aware of a place that this can be done currently as the balancer willy only attempt another backend on connection failure only.

-- 
Daniel Ruggeri