[stunnel-users] Problem with roundrobbin failover mode?

[Matt Wise]

This is odd, but we're seeing failures again with this config. We're seeing that with delay=yes, and 6 total connection targets (5 servers, 1 ELB), stunnel picks up the first connection (the ELB) and never uses any of the other targets. Ever. If we use tcpkill to block access to the ELB, we end up completely screwed.

Anyone else seeing this as a problem still?

On Jan 7, 2013, at 12:39 PM, Matt Wise <matt at nextdoor.com> wrote:

> Ah. Thats it! I also see a fix in 4.54, am I right?
>> "delay = yes" fixed to work even if specified *after* "connect" option.
>> Multiple "connect" targets fixed to also work with delayed resolver.
> --Matt
> 
> On Jan 7, 2013, at 11:39 AM, Michal Trojnara <Michal.Trojnara at mirt.net> wrote:
> 
>> Hi Matt,
>> 
>> Load balancing is incompatible with delayed resolver.  Remove "delay =
>> yes" from your configuration file.
>> 
>> Mike
>> 
>> On 2013-01-07 18:38, Matt Wise wrote:
>>> I've got dozens of clients connecting with Stunnel to a group of 5 servers. Each system has a config that looks like this:
>>> 
>>>> cert = /etc/stunnel/zookeeper.pem
>>>> key = /etc/stunnel/zookeeper.key
>>>> CAfile = /etc/stunnel/zookeeper_ca.pem
>>>> verify = 2
>>>> delay = yes
>>>> sslVersion = TLSv1
>>>> client = yes
>>>> setuid = stunnel4
>>>> setgid = stunnel4
>>>> pid = /var/lib/stunnel4/zookeeper.stunnel4.pid
>>>> socket = l:TCP_NODELAY=1
>>>> socket = r:TCP_NODELAY=1
>>>> TIMEOUTconnect = 2
>>>> session = 86400
>>>> debug = 5
>>>> [zookeeper]
>>>> accept  = 127.0.0.1:2182
>>>> failover = rr
>>>> connect = prod-zookeeper:2182
>>>> connect = prod-zookeeper-1:2182
>>>> connect = prod-zookeeper-2:2182
>>>> connect = prod-zookeeper-3:2182
>>>> connect = prod-zookeeper-4:2182
>>>> connect = prod-zookeeper-5:2182
>>> 
>>> Essentially the first host is a load balancer, and the next 5 are the actual zookeeper hosts so that we can bypass the ELB if its giving us fits. Now what we're seeing is that almost every connection ends up on prod-zookeeper-5. Over and over and over again, our hosts pick the same system each time. We're running Stunnel 4.52:
>>> 
>>>> Clients allowed=8000
>>>> stunnel 4.52 on i486-pc-linux-gnu platform
>>>> Compiled/running with OpenSSL 0.9.8k 25 Mar 2009
>>>> Threading:PTHREAD SSL:ENGINE Auth:LIBWRAP Sockets:POLL,IPv6
>>> 
>>> Any ideas what might be wrong here? Obviously we want the connections to be *roughly* random across the list of hosts... and if one of the hosts goes down, and the connection fails, we want the stunnel service to try again, and randomly pick a new host. It doesn't really seem to be doing that though. 
>>> 
>>> --Matt
>>> 
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>> 
>> 
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