[ale] Does anybody have experience with a load-balancing/failover distro?

[Michael Trausch]

On Tue, Sep 28, 2010 at 6:27 PM, Richard Bronosky <Richard at bronosky.com> wrote:
> What you describe is a failover, not a load balancer. If you have 2
> good connections it would be a shame not to use them.

Well, yes.  The subject did include “failover”.  :-)

While I am quite sure that it would be possible to load-balance with
NAT connections, I don't think it would be terribly useful.  I often
see a place that will have a high-speed primary link, and a very low
speed backup link.  Failover is far more appropriate.

Now, if some place has two identical links that come in different
ways, way, a T1 from place A and a T1 from place B, and there were a
way to bond the two together such that they would work as a single
virtual pipe and subsequently suffer the failure of one of them, then
I think that load-balancing would be quite appropriate.  But I have
yet to encounter such a situation, personally.

    -- Mike

> On 9/28/10, Michael Trausch <mike at trausch.us> wrote:
>> You should be able to do this with any distribution.  You need only to have:
>>   * Setup eth0 with the first connection
>>   * Setup eth1 with the second connection
>>   * Setup eth2 as the LAN's RFC1918 space and have it answer DHCP and
>> do all the "normal" things.
>>
>> Now, write your iptables rules for Internet-through-eth0 and create a
>> modified copy of that for Internet-through-eth1.
>>
>> Now, keep a file, say, /var/run/active-connection, that has the name
>> of the currently active connection in it (either eth0 or eth1).
>>
>> Have a cron job that, once per minute, pings the gateway address for
>> whatever interface is listed in /var/run/active-connection.  If it is
>> down, then reconfigure the routing table and IP masquerading for the
>> second connection, mark the change in /var/run/active-connection, and
>> go from there.
>>
>> I'd leverage /etc/network/interfaces on Debian and derivatives.  All
>> you need to do is hook into that so that "ifdown eth0" and "ifup eth1"
>> are all you need, and you should probably have it setup so that you
>> cannot "ifup" on both interfaces at the same time, unless you have a
>> static IP address from both ISPs.
>>
>> I haven't gotten around to it yet, but what I would like to do is
>> create a little embedded doohickey that will do just this, with three
>> Ethernet ports (two in, one out) and a USB port for configuration
>> (serial ports don't exist on modern systems anymore, so might as well
>> just use a USB port and make it act like a serial port...).  And the
>> default configuration of the device would just be for a standard
>> network with two standard DHCP-providing ISPs, such that a "completely
>> standard" setup would Just Work.  Me being me, I'll probably (when I
>> get to it) even have the thing create an IPv6 tunnel and advertise
>> IPv6 connectivity, because I just can't see the point of not doing so.
>>  :-)
>>
>>    --- Mike
>>
>> On Tue, Sep 28, 2010 at 12:08 PM, david w. millians <millia at panix.com>
>> wrote:
>>>
>>> I've got a district that is getting a second internet connection for
>>> redundancy purposes. They would therefore love to have a load balancing
>>> and failover appliance. Obviously, there are some vendors that have
>>> products to sell them, and also obviously, they cost money that they
>>> don't have.
>>>
>>> A fair number of districts have used "untangle" before, but it appears
>>> that they charge for the lb/f capability; it's not included in the free
>>> download. It may be cheaper for them since they don't need firewall,
>>> filtering, etc., but free is preferred, since even the box to do this is
>>> a factor...
>>>
>>> So, do you know of/have you used any linux distros that do this well and
>>> easily? I'm going to go to distrowatch now, but I just want to know of
>>> good experiences.
>>>
>>> Thanks,
>>> David
>>> _______________________________________________
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>
> --
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>
> .!# RichardBronosky #!.
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