Hi [email protected],
My current project at work is a two node cluster running apache and virtual IPs
on CentOS 7. I found in my testing that apache when run by corosync does not
have a reload or graceful restart. Before the cluster, when apache was a single
instance, I previously used graceful restart to be able to add configurations
with out affecting current users of the system.
Initially, I tried adding the capability myself as a resource action in the pcs
configuration, I was able to add the action, but it would have no effect when
run. Digging deeper, I eventually found the apache control script at
/usr/lib/ocf/resource.d/heartbeat/apache and was able to see that there are no
commands available for a graceful restart, only graceful stop.
Currently, I have found two ways of getting around this limitation. The first
is “/bin/kill -USR1 `cat /var/run/httpd.pid`", and the second is "/bin/test -f
/var/run/httpd.pid && /usr/sbin/httpd -f /etc/httpd/conf/httpd.conf -c "PidFile
/var/run/httpd.pid" -k graceful”. Both seem to work with out adversely
affecting corosync.
My primary question is; what is the reason that graceful restart is not
supported by the heartbeat apache control script? It seems like a pretty common
usage of apache, so it seems a strange omission from the script. I am concerned
that I’m trying to work against the grain since it is absent from the script.
My second question is; are the two work arounds presented above safe for use
with corosync/heartbeat/pcs? Is one preferable to the other? If neither are
safe, how would you recommend being able to update apache configurations with
no downtime?
I am new to this list and could not find a way to search the archives, so if
this question has already been answered, could you point me to the search area
and to the answer as well?
Thank you in advance for your advice and recommendations.
-Cole
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