====== Memcached ======

**General Information**

Memcached is a "distributed memory object caching system". Useful for speeding up web applications by caching database lookups.

Official Site: http://www.memcached.org/

**Checklist**
  * Distro(s): Enterprise Linux
  * Repo: [[linux_wiki:repos#epel|EPEL]] (if using EL 5/6)

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====== Install Memcached ======

  - Memcached is in EL 7's base repo. If you are using EL 5/6, you will need to add the EPEL repo.
    - Add the [[linux_wiki:repos#epel|EPEL repo]]
  - Install memcached<code bash>yum install memcached</code>
  - Start and enable the service
    - EL 6<code bash>service memcached start
chkconfig memcached on</code>
    - EL 7<code bash>systemctl start memcached
systemctl enable memcached</code>

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====== Configure Memcached ======

  * Edit the config file<code bash>vim /etc/sysconfig/memcached

# Daemon
USER="memcached"
 
# Reserved Cache in MBs
CACHESIZE="2048"
 
# Memcached Options - Listen on localhost only
OPTIONS="-l 127.0.0.1"

# Memcached Options - Clear out to listen on any interface
#OPTIONS=""

# Networking
PORT="11211"
MAXCONN="1024"</code>
    * OPTIONS => Set other daemon options (see man memcaced)
  * If you made any config file changes, restart the service.

===== Secure Memcached =====

Memcached does not have any application authentication, so you should configure the memcached server with firewall rules to only allow certain sources to utilize it on tcp and udp port 11211 (the default port).
  * Either listen locally, or setup firewall rules to protect the cache.
    * See pages on [[linux_wiki:firewall_firewall-cmd|Firewall-cmd]] or [[linux_wiki:firewall_iptables|IPTables]] for syntax details.

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