Problem using CARP + HAST ...

[Mikolaj Golub]

On Mon, 8 Aug 2011 16:54:10 +0200 Ferdinand Goldmann wrote:

 FG> Hi!

 FG> I am trying to create a common resource pool for a certain application using
 FG> CARP/HAST as described in [1]. However while testing my setup I ran into a
 FG> problem which I don't know how to fix or work around:

 FG> If I shut down only the carp interface on the master (ifconfig carp0 down),
 FG> the slave will take note of this, make his carp interface the master and
 FG> mount the HAST storage using a script called by devd. Everything fine so far. BUT:

 FG> If, however, I completely shut down the masters network connection (using "shut" on
 FG> the switchport), the carp interface on the slave will still switch to master. 
 FG> But the script for making the HAST storage primary will just hang forever:

 FG> root  46841  0.0  0.6  3628  1524  ??  S     4:21PM   0:00.08 /bin/sh /opt/bin/carp-hast-switch master
 FG> root  47043  0.0  2.6 42228  6580  ??  S     4:22PM   0:00.03 hastd: hast0 (secondary) (hastd)

 FG> Seemingly, this is because the hastd daemons on master and slave are unable to 
 FG> communicate. So the script waits forever for the secondary device to go away... :

 FG>            # Wait for any "hastd secondary" processes to stop
 FG>            for disk in ${resources}; do
 FG>            while $( pgrep -lf "hastd: ${disk} \(secondary\)" > /dev/null 2>&1 ); do
 FG>                 sleep 1
 FG>                 done

What freebsd are you running on? I suppose it is release, because on STABLE
this issue should be fixed -- the secondary terminates after timeout.

 FG> Im a bit puzzled. Is there a way for hastd to make himself the master in case of a timeout
 FG> or such? Because in normal operation, whenever the carp interface fails, the underlying 
 FG> infrastructure will most likely be down as well.

On release you can just modify the script not to wait forever for hastd
secondary to stop -- it will be terminated when the role is switched to
primary.

But anyway my advise is to use STABLE :-).

-- 
Mikolaj Golub