|
On Sat, Apr 01, 2000 at 11:53:14AM -0500, Joseph Mack wrote:
> On Fri, 31 Mar 2000, jake buchholz wrote:
> > Anyone have any success getting mysql to successfully connect through
> > LVS?
>
> a previous posting sounded like someone had got http and mysql realservers
> running behind a director. The httpds had their own VIP (which the
> client connected to) and they called the mysqlds, which had a separate
> VIP (each realserver had httpd or mysqld but not both).
That was me. In theory, that appeared to be the solution, but I didn't
have the opportunity to thoroughly test it at that point.
> I would expect that mysqld is just another single port service (although
> I haven't tried it). If it didn't work out of the box I'd be interested
> to know why.
I'd expect so as well, but it doesn't appear to be the case...
> > I can connect fine on the real server, but can't connect through the
> > LVS redirector...
>
> the control (eg another service like telnet) works fine?
Yep. Telnet, SSL, HTTP, HTTPS, FTP all working fine.
> Is mysqld listening on the VIP (if you're running VS-DR) or the RIP
> (if you're running VS-NAT)?
mysqld (by default, at least) listens on all interfaces. The VIP is up
on the box.
'mysql -h<VIP>' works fine on the mysql real server, but won't work from
anywhere else.
> > I can't just telnet to port 3309 from the real or
> > through the LVS though -- so my guess is that mysql is sensing that
> > something isn't quite right and refusing the connection...
> to make progress from here you're going to have to run tcpdump on the
> director and the realserver.
on the mysql real server...
tcpdump dst host <VIP>
when i'm on the mysql real server, I connect with 'mysql -h<VIP>' successfullly
and I'm seeing tcpdump traffic.
if, from an outside box, I successfully connect to the real server via
'mysql -h<RIP>', no tcpdump output, obviously.
if, from an outside box, I want to connect via 'mysql -h<VIP>', the connect
fails, and I'm not seeing any tcpdump output on the mysql real server.
on the redirector...
tcpdump host <RIP> or host <VIP>
from an outside box trying to connect via 'mysql -h<VIP>', I'm seeing two
lines:
12:52:52.654440 eth0 < <OIP>.62710 > <VIP>.mysql: S 2856299978:2856299978(0)
win 32120 <mss 1460,sackOK,timestamp 264231195 0,nop,wscale 0> (DF)
12:52:52.654481 eth0 > <VIP>.mysql > <OIP>.62710: R 0:0(0) ack 2856299979 win 0
here's the ipvsadm -L info:
TCP <VIP>:3309 rr
-> <RIP>:3309 Route 1 0 0
If you'd like me to run more specific tcpdumps, let me know what they should
be...
> > the LVS -> real server for databases are 1:1.
> I'm sorry I don't know what this means
One mysql <VIP> -> one mysql <RIP>
> what i'd like to use it
> > for is to be able to switch to a different mysql real server if one goes
> > down (for maintenance, etc.)
>
> so need a monitor for mysqld?
Not really.
> or to redistribute the databases if we add
> > a new mysql real server.
>
> I would expect that multiple mysqlds will have to access the same
> file system (eg by nfs, other people are talking about gfs, but I
> don't know if anyone has got it to work with LVS yet)
Haven't heard about gfs, but yes, the databases are served to the mysql real
servers via nfs.
--
Jake Buchholz, Senior Systems Administrator : /~\
ExecPC (a Voyager.net company, NASDAQ: VOYN) : ASCII \ / Against
Voyager.net Hosting Solutions Lead R&D Engineer : Ribbon X HTML
GnuPG (PGP5/6) and PGP 2.6.2 pub keys available : Campaign / \ Mail
|
