Date: Fri, 11 Nov 2005 09:38:09 -0500 From: DAve <dave.list@pixelhammer.com> To: freebsd-questions@freebsd.org Subject: Re: Carp and Apache Message-ID: <4374ACD1.2030303@pixelhammer.com> In-Reply-To: <20051104232635.GT18563@ratchet.nebcorp.com> References: <435D5303.3030906@pixelhammer.com> <20051104232635.GT18563@ratchet.nebcorp.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Danny Howard wrote:
> Dave,
>
> Yes.
"Yes" both apache servers have the same IP in httpd.conf? or "Yes" I am
completely off base in my understanding?
Not certain I can go this route right now anyway as I do not have enough
test boxes to setup a trial. There seems to be a shortage of good docs
on using CARP outside of using it with PF.
Thanks,
DAve
>
> The trick with CARP is that it is an IP-level heartbeat, so if you are
> running Apache, you want to "carp up" after you start apache, and "carp
> down" before you stop Apache.
>
>>From some test boxes, web0:
> ifconfig_fxp1="inet 192.168.1.210 netmask 255.255.255.0"
> defaultrouter="192.168.1.1"
> cloned_interfaces="carp0 carp1"
>
> Then, web0 application config file:
> export CARP_PASS="mekmitasdigoat"
> # MASTER
> export CARP_carp0_IP=192.168.1.206
> export CARP_carp0_VHID=1
> # SLAVE
> export CARP_carp1_IP=192.168.1.207
> export CARP_carp1_VHID=2
> export CARP_carp1_SKEW=100
>
> Next, the Application "control" script:
> # CARP
> carp_ifs=`ifconfig -l | tr ' ' '\n' | grep carp`
>
> # Set up CARP
> for carp_if in $carp_ifs; do
> eval carp_ip=\$CARP_${carp_if}_IP
> eval carp_vhid=\$CARP_${carp_if}_VHID
> eval carp_skew=\$CARP_${carp_if}_SKEW
>
> if [ -n "$carp_vhid" ]; then
> carp_vhid="vhid $carp_vhid"
> fi
> if [ -n "$carp_skew" ]; then
> carp_skew="advskew $carp_skew"
> fi
>
> if [ -n "${carp_ip}" -a -n "${carp_vhid}" ]; then
> ifconfig $carp_if pass "$CARP_PASS" $carp_vhid $carp_skew $carp_ip
> ifconfig $carp_if down
> else
> echo "WARNING: $carp_if but missing CARP_${carp_if}_IP or CARP_${carp_if}_VHID!"
> fi
> done
>
> [... later ...]
> if [ $status -eq 0 ]; then
> echo "Apache successfully ${cmd}ed"
> echo "Ready to CARP UP!"
> if [ -n "${carp_ifs}" ]; then
> for carp_if in $carp_ifs; do
> eval carp_ip=\$CARP_${carp_if}_IP
> eval carp_vhid=\$CARP_${carp_if}_VHID
> if [ -n "${carp_ip}" -a -n "${carp_vhid}" ]; then
> ifconfig $carp_if up
> fi
> done
> sysctl net.inet.carp.preempt=1
> fi
> else
> echo "Apache failed to $cmd"
> exit 2
> fi
>
>
> Okay, so that's really quite a mess, but basically:
> * Set cloned_interfaces in rc.conf to create carp<n> at boot.
> * One IP alias and VHID per CARP IP.
> * Set up the backup server with higher advskew.
> * For availability, teach you apachectl script to ifconfig the carp
> interfaces, ifconfig down, start apache, ifconfig up, and ifconfig
> down before stopping / restarting apache.
>
> Cheers,
> -danny
>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4374ACD1.2030303>