SCENARIO
We want to store session in a different server for our 2 web clients in the cluster
So we have 3 servers:
session=10.10.4.29 (session server) web1=10.10.4.21 web2=10.10.4.22
SERVER (session:10.10.4.29)
$ sudo yum update
$ sudo yum install memcached
$ sudo vi /etc/sysconfig/memcached
PORT=”11211″
USER=”memcached”
MAXCONN=”1024″
CACHESIZE=”64″
OPTIONS=””
MEMCACHED COMMANDS
$ sudo systemctl start memcached
$ sudo systemctl status memcached
$ sudo systemctl enable memcached
$ sudo systemctl stop memcached
$ sudo systemctl restart memcached
FIREWALL
$ sudo firewall-cmd --permanent --zone=public --add-port=11211/tcp
$ sudo firewall-cmd --reload
confirm memcached running status
$ memcached-tool 127.0.0.1:11211 stats
#127.0.0.1:11211 Field Value
accepting_conns 1
auth_cmds 0
auth_errors 0
vbytes 0
bytes_read 7
bytes_written 0
cas_badval 0
cas_hits 0
cas_misses 0
cmd_flush 0
cmd_get 0
cmd_set 0
cmd_touch 0
conn_yields 0
connection_structures 11
curr_connections 10
curr_items 0
decr_hits 0
decr_misses 0
delete_hits 0
delete_misses 0
evicted_unfetched 0
evictions 0
expired_unfetched 0
get_hits 0
get_misses 0
hash_bytes 524288
hash_is_expanding 0
hash_power_level 16
incr_hits 0
incr_misses 0
libevent 2.0.21-stable
limit_maxbytes 67108864
listen_disabled_num 0
pid 3988
pointer_size 64
reclaimed 0
reserved_fds 20
rusage_system 0.007483
rusage_user 0.001247
threads 4
time 1509482646
total_connections 11
total_items 0
touch_hits 0
touch_misses 0
uptime 73
version 1.4.15
$ sudo netstat -tulpn | grep :11211
tcp 0 0 0.0.0.0:11211 0.0.0.0:* LISTEN 4106/memcached tcp6 0 0 :::11211 :::* LISTEN 4106/memcached udp 0 0 0.0.0.0:11211 0.0.0.0:* 4106/memcached udp6 0 0 :::11211 :::* 4106/memcached
CLIENT (WEB1 and WEB2)
install first nmap and netstat
$ sudo yum install nmap netstat
install memcache
$ sudo yum install memcached
point session server both on web1 and web2
$ sudo vi /etc/hosts
10.10.4.29 session
check the remote connectivity from client server(web1 and web2)
$ echo stats | nc session 11211
$ echo stats | nc 10.10.4.29 11211
STAT pid 3988 STAT uptime 423 STAT time 1509482996 STAT version 1.4.15 STAT libevent 2.0.21-stable STAT pointer_size 64 STAT rusage_user 0.007939 STAT rusage_system 0.013232 STAT curr_connections 10 STAT total_connections 12 STAT connection_structures 11 STAT reserved_fds 20 STAT cmd_get 0 STAT cmd_set 0 STAT cmd_flush 0 STAT cmd_touch 0 STAT get_hits 0 STAT get_misses 0 STAT delete_misses 0 STAT delete_hits 0 STAT incr_misses 0 STAT incr_hits 0 STAT decr_misses 0 STAT decr_hits 0 STAT cas_misses 0 STAT cas_hits 0 STAT cas_badval 0 STAT touch_hits 0 STAT touch_misses 0 STAT auth_cmds 0 STAT auth_errors 0 STAT bytes_read 13 STAT bytes_written 1023 STAT limit_maxbytes 67108864 STAT accepting_conns 1 STAT listen_disabled_num 0 STAT threads 4 STAT conn_yields 0 STAT hash_power_level 16 STAT hash_bytes 524288 STAT hash_is_expanding 0 STAT bytes 0 STAT curr_items 0 STAT total_items 0 STAT expired_unfetched 0 STAT evicted_unfetched 0 STAT evictions 0 STAT reclaimed 0 END
check if memcached exists
$ php -i | grep memcached
/etc/php.d/z-memcached.ini, memcached memcached support => enabled libmemcached version => 1.0.16 memcached.compression_factor => 1.3 => 1.3 memcached.compression_threshold => 2000 => 2000 memcached.compression_type => fastlz => fastlz memcached.default_binary_protocol => no value => no value memcached.default_connect_timeout => 0 => 0 memcached.default_consistent_hash => no value => no value memcached.serializer => igbinary => igbinary memcached.sess_binary_protocol => 1 => 1 memcached.sess_connect_timeout => 1000 => 1000 memcached.sess_consistent_hash => 1 => 1 memcached.sess_lock_expire => 0 => 0 memcached.sess_lock_max_wait => not set => not set memcached.sess_lock_retries => 5 => 5 memcached.sess_lock_wait => not set => not set memcached.sess_lock_wait_max => 2000 => 2000 memcached.sess_lock_wait_min => 1000 => 1000 memcached.sess_locking => 1 => 1 memcached.sess_number_of_replicas => 0 => 0 memcached.sess_persistent => no value => no value memcached.sess_prefix => memc.sess.key. => memc.sess.key. memcached.sess_randomize_replica_read => no value => no value memcached.sess_remove_failed_servers => no value => no value memcached.sess_sasl_password => no value => no value memcached.sess_sasl_username => no value => no value memcached.sess_server_failure_limit => 0 => 0 memcached.store_retry_count => 2 => 2 Registered save handlers => files user redis rediscluster memcached session.save_handler => memcached => memcached
or check the module itself
$ php -m | grep memcache
memcached
If you still don’t see the memcached then install the php memcache
$ sudo yum install php71w-pecl-memcached
uncomment save_handler to force it seen in phpinfo()
$ sudo vi /etc/php.d/z-memcached.ini
session.save_handler=memcached
restart memcached on the server and nginx & php-fpm on each web client
$ sudo systemctl restart memcached (on session server)
$ sudo systemctl restart nginx
$ sudo systemctl restart php-fpm
put info.php file under each web server /usr/share/nginx/html/info.php
$ sudo vi /usr/share/nginx/html/info.php
Now you should see memcached library in each part
TEST
implement a test script
$ sudo vi /usr/share/nginx/html/testmemcached.php
<?php
addServer("10.10.4.29", 11211);
$result = $mc->get("test_key");
if($result) {
echo $result;
} else {
echo "No data on Cache. Please refresh page pressing F5";
$mc->set("test_key", "test data pulled from Cache!") or die ("Failed to save data at Memcached server");
}
?>
go to web1 and web2 directly
http://10.10.4.21/testmemcached.php
http://10.10.4.22/testmemcached.php
Finally go to the config.php in moodle and enable the session handler block
$ sudo vi /usr/share/nginx/html/config.php
// Memcached session handler (requires memcached server and extension): $CFG->session_handler_class = '\core\session\memcached'; $CFG->session_memcached_save_path = ’10.10.4.29:11211'; $CFG->session_memcached_prefix = 'memc.sess.key.'; $CFG->session_memcached_acquire_lock_timeout = 120; $CFG->session_memcached_lock_expire = 7200; // Ignored if PECL memcached is below version 2.2.0
Your testmemcached.php is correct? It seems to me that <?php is missing
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Yes it’s correct, why not?
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Oh yeah you are right, just realized it.. Thanks, I fixed it
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