[CentOS] multiple memcached buckets in CentOS 7

[Tim Dunphy]

Hi again Alberto,


With systemd it will be as easy as creating additional unit files ( one for
each memcached instance) with its corresponding config file.  That should
allow to stop / start / restart  each memcache instance individually while
also being systemd compliant.


I just wanted to say thank you again for your advice. Worked like a charm!

[root at web1:~] #systemctl start memcached.service

[root at web1:~] #lsof -i :11211 | head -5
COMMAND     PID      USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME
memcached 20604 memcached   26u  IPv4 10415567      0t0  TCP *:memcache
(LISTEN)
memcached 20604 memcached   27u  IPv6 10415568      0t0  TCP *:memcache
(LISTEN)
memcached 20604 memcached   28u  IPv4 10415571      0t0  UDP *:memcache
memcached 20604 memcached   29u  IPv4 10415571      0t0  UDP *:memcache

[root at web1:~] #systemctl start memcached-11212.service

[root at web1:~] #systemctl start memcached-11212.service
[root at web1:~] #lsof -i :11212
COMMAND     PID      USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME
memcached 20635 memcached   26u  IPv4 10415718      0t0  TCP *:11212
(LISTEN)
memcached 20635 memcached   27u  IPv6 10415719      0t0  TCP *:11212
(LISTEN)
memcached 20635 memcached   28u  IPv4 10415722      0t0  UDP *:11212
memcached 20635 memcached   29u  IPv4 10415722      0t0  UDP *:11212
memcached 20635 memcached   30u  IPv4 10415722      0t0  UDP *:11212
memcached 20635 memcached   31u  IPv4 10415722      0t0  UDP *:11212
memcached 20635 memcached   32u  IPv6 10415723      0t0  UDP *:11212
memcached 20635 memcached   33u  IPv6 10415723      0t0  UDP *:11212
memcached 20635 memcached   34u  IPv6 10415723      0t0  UDP *:11212
memcached 20635 memcached   35u  IPv6 10415723      0t0  UDP *:11212

I ran my demonstration on ports 11211 and 11212 as you can see above. I
really appreciate the info you've provided and have stored that in my notes
for myself and others to use.

Best regards,
Tim




On Wed, Mar 18, 2015 at 12:16 PM, Tim Dunphy <bluethundr at gmail.com> wrote:

> Hi Alberto,
>
> With systemd it will be as easy as creating additional unit files ( one for
>> each memcached instance) with its corresponding config file.  That should
>> allow to stop / start / restart  each memcache instance individually while
>> also being systemd compliant.
>
>
> Thanks for the info and for the examples. It really does make sense the
> way you explain it. Thanks for letting me know!
>
> Best regards,
> Tim
>
> On Wed, Mar 18, 2015 at 1:06 AM, Alberto Rivera Laporte <
> arlaporte at gmail.com> wrote:
>
>> >
>> >
>> > Now, under CentOS 7, I see we have two files controlling memcached under
>> > the new sysctl system. At least, using sysctl is new to me!
>> >
>> > I see we have this file:
>> >
>> > [root at web1:~] #cat  /usr/lib/systemd/system/memcached.service
>> > [Unit]
>> > Description=Memcached
>> > Before=httpd.service
>> > After=network.target
>> >
>> > [Service]
>> > Type=simple
>> > EnvironmentFile=-/etc/sysconfig/memcached
>> > ExecStart=/usr/bin/memcached -u $USER -p $PORT -m $CACHESIZE -c $MAXCONN
>> > $OPTIONS
>> >
>> > [Install]
>> > WantedBy=multi-user.target
>> >
>> > And we have this one under sysconfig:
>> >
>> > [root at web1:~] #cat /etc/sysconfig/memcached
>> > PORT="11211"
>> > USER="memcached"
>> > MAXCONN="1024"
>> > CACHESIZE="64"
>> > OPTIONS=""
>> >
>> > So I'm trying to figure out how to achive the same effect that I would
>> > under the old init script way of doing things.
>> >
>> > Can someone please give me an example of how to get the same thing done
>> > under the new system?
>> >
>> >
>> As you said earlier on earlier ( non-systemd) versions of the memcached
>> init scripts, you would define all instances of memcache under the start
>> function.
>>
>> With systemd it will be as easy as creating additional unit files ( one
>> for
>> each memcached instance) with its corresponding config file.  That should
>> allow to stop / start / restart  each memcache instance individually while
>> also being systemd compliant.
>>
>>
>> Examples:
>>
>> ## first instance ##
>> #  /usr/lib/systemd/system/memcached.service
>> [Unit]
>> Description=Memcached
>> Before=httpd.service
>> After=network.target
>>
>> [Service]
>> Type=simple
>> EnvironmentFile=-/etc/sysconfig/memcached
>> ExecStart=/usr/bin/memcached -u $USER -p $PORT -m $CACHESIZE -c $MAXCONN
>> $OPTIONS
>>
>> #  /etc/sysconfig/memcached
>> PORT="11211"
>> USER="memcached"
>> MAXCONN="1024"
>> CACHESIZE="64"
>> OPTIONS=""
>> ## end first instance
>>
>> ## second instance ##
>>
>> ## second instance ##
>> #  /usr/lib/systemd/system/memcached-11214.service
>> [Unit]
>> Description=Memcached-11214
>> Before=httpd.service
>> After=network.target
>>
>> [Service]
>> Type=simple
>> EnvironmentFile=-/etc/sysconfig/memcached-11214
>> ExecStart=/usr/bin/memcached -u $USER -p $PORT -m $CACHESIZE -c $MAXCONN
>> $OPTIONS
>>
>> #  /etc/sysconfig/memcached-11214
>> PORT="11214"
>> USER="memcached"
>> MAXCONN="1024"
>> CACHESIZE="64"
>> OPTIONS=""
>> ## end second instance
>>
>> Lastly enable each service if not already enabled:
>> # instance 1
>> systemctl enable /usr/lib/systemd/system/memcached.service
>> systemctl start memcached.service
>>
>> # instance 2
>> systemctl enable /usr/lib/systemd/system/memcached-11214.service
>> systemctl start memcached-11214.service
>>
>> You can also still use legacy sysv init scripts as there is support for
>> backwards compatibility however the systemd approach is much simpler while
>> adhering to the systemd standard.
>>
>> Good luck.
>> _______________________________________________
>> CentOS mailing list
>> CentOS at centos.org
>> http://lists.centos.org/mailman/listinfo/centos
>>
>
>
>
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