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I can give that a try. In the past when I tried editing the
ldirectord.cf file to drain servers, I recall that LVS stopped
forwarding packets to them completely. Users with existing sessions
experienced "freezes".
--
Eric Robinson
-----Original Message-----
From: lvs-users-bounces@xxxxxxxxxxxxxxxxxxxxxx
[mailto:lvs-users-bounces@xxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Jason
Ledford
Sent: Friday, December 05, 2008 9:47 AM
To: LinuxVirtualServer.org users mailing list.
Subject: Re: [lvs-users] How to Tell If an RS Is Really Up
I use the command (already posted) to drain the server using ldirectord
config file:
/bin/sed 's/ real=10.37.2.9:25 masq 1/ real=10.37.2.9:25
masq 0/g' $
I put that in a script and can run it when needed to drain my servers.
I also have the reverse in a script so I can bring it back when I need.
I back it up first in case of a mistake. I take it a step further and
run these scripts from Webmin so there is no need to even login to the
server.
-----Original Message-----
From: lvs-users-bounces@xxxxxxxxxxxxxxxxxxxxxx
[mailto:lvs-users-bounces@xxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Robinson,
Eric
Sent: Friday, December 05, 2008 11:57 AM
To: LinuxVirtualServer.org users mailing list.
Subject: Re: [lvs-users] How to Tell If an RS Is Really Up
That solidifies what was taking shape in my mind. Thanks for the
clarification.
It seems this is a very timely discussion.
> three modes might make sense:
>
> 1. Ignore them (until a change event occurs) - the current behavior
> 2. Reverse them - the behavior you were originally expecting 3.
> Incorporate them into the configuration
This makes a great deal of sense to me. I can see where all three
options could be useful, but I really don't want to be without option 1.
It is what makes what I call "drain mode" possible, which is a
wonderfully graceful way to maintain servers. I set the weight to 0 then
I go away. Existing sessions continue uninterrupted, but new ones to
that RS are not possible. The user count gradually drops to zero, at
which time I am free to power off the server or whatever. No advance
notification to users is required. No staying up late to catch the
server when nobody is on it. I just put it in drain mode during normal
production hours. The next day when all the users are off of it, I can
maintain it at my convenience. When I'm done, I issue an ipvsadm command
to put the server in "fill mode" and it starts servicing clients. I've
been using this approach for a year and it has saved enormous amounts of
time and energy.
> Personally, I would be a lot more comfortable in altering LVS's setup
> by modifying ldirectord.cf as needed. As you never know when an event
> that triggers ldirectord to do something might occur.
For that very reason, the current behavior seems perfect to me. When I
place a server in "administratively down" mode, I *want* LVS to ignore
commands that may be triggered by ldirectord's health checks. That way I
can maintain the services on the RS (stop and start tomcat, for
instance) and not worry about the server suddenly becoming available to
users.
I also like being able to manipulate this behavior from the command
line. No need to edit a config file (or worry about remembering to
un-edit it). I can even schedule drain/fill changes with the at command.
It just feels right to me.
Of course, I know you must keep the big picture in mind. I hope whatever
you eventually do, the current behavior remains doable somehow.
--
Eric Robinson
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_______________________________________________
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Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
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