PHP session handler using redis not work

PHPphp.iniredis

I was sets 3 servers :

192.168.7.147:6379 <-- redis server
192.168.7.162 <-- web server 1 (using phpredis, with local devdomain jttest.com )
192.168.7.218 <-- web server 1 (using phpredis, with local devdomain jttest.com )

both of 192.168.7.162 and 192.168.7.218 using php.ini configuration exactly like these :

extension=redis.so
session.save_handler = redis
session.save_path = tcp://192.168.7.147:6379

also i have restart apache and redis too after altering these option, of course i can use basic function of redis inside my php code

The problems starts here, i can login on 192.168.7.162 using php standard session call (session_start())
but the session cannot be retrieved on 192.168.7.218 and vice versa, in simple word, redis session not shared.

inside 192.168.7.147 , i was unable to get keys related to the session (session name is PHPREDIS_SESSION), look these result i get from redis-cli

redis 127.0.0.1:6379> keys *
1) "attribute"
2) "test"
redis 127.0.0.1:6379>

one more thing, at 192.168.7.218 php still saves the session using files, not using redis

[root@centos_wira_devel session]# ll
total 8
-rw------- 1 apache apache 792 Feb 26 16:29 sess_1nm86s67o1o696cgopmrc2hq75
-rw------- 1 apache apache 792 Feb 26 16:41 sess_hhmompfoqjh0emoofppg4v5lp2

for information, in my browser, cookie for session (both of 192.168.7.162 and 192.168.7.218) saved as ['PHPREDIS_SESSION'] = hhmompfoqjh0emoofppg4v5lp2

in page phpredis i didnt found any FAQ about this case (https://github.com/phpredis/phpredis), i didn't know where the step i'm missing.

Best Answer

Sessions settings may be altered in other configuration files, except php.ini. This may be confirmed checking the "session" section of phpinfo() output. If the values in column "Local Value" are different of those in column "Master Value", other files must be inspected.
Specifically in Centos, on server 192.168.7.162, it is very probable to have the session.save_handler set to "files", in /etc/httpd/conf.d/php.conf .

Related Solutions

Nginx Alias Causing phpMyAdmin Login Endless Loop – Fix

I had the exact same problem. I ran a website with a doc root in /var/www/somesite and wanted to hook phpmyadmin to some sub-folder on the site. I tried this with this config in nginx:

root /var/www/somesite;

location /pma/ {
    alias /usr/share/phpmyadmin/;
}

location ~ ^/pma/(.+\.php)$ {
    alias /usr/share/phpmyadmin/$1;
    fastcgi_pass   unix:/tmp/phpfpm.sock;
    fastcgi_index  index.php;
    fastcgi_param  SCRIPT_FILENAME  $request_filename;
    include fastcgi_params;
}

This seemed to work, except when I logged in, like you described, I just saw the front page again. No errors, nothing. If I logged in with a bad password, I got a "Cannot login to MySQL server"-error, as you'd expect.

Solution
Finally what I did was I dragged in all the stuff from fastcgi_params and found that changing the DOCUMENT_ROOT-parameter fixed this. So the nginx-config above changed to:

root /var/www/somesite;

location /pma/ {
    alias /usr/share/phpmyadmin/;
}

location ~ ^/pma/(.+\.php)$ {
    alias /usr/share/phpmyadmin/$1;
    fastcgi_pass   unix:/tmp/phpfpm.sock;
    fastcgi_index  index.php;
    fastcgi_param  SCRIPT_FILENAME  $request_filename;

    # From fastcgi_params
    fastcgi_param  QUERY_STRING       $query_string;
    fastcgi_param  REQUEST_METHOD     $request_method;
    fastcgi_param  CONTENT_TYPE       $content_type;
    fastcgi_param  CONTENT_LENGTH     $content_length;
    fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
    fastcgi_param  REQUEST_URI        $request_uri;
    fastcgi_param  DOCUMENT_URI       $document_uri;
    fastcgi_param  DOCUMENT_ROOT      /usr/share/phpmyadmin; # <-- Changed
    fastcgi_param  SERVER_PROTOCOL    $server_protocol;
    fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
    fastcgi_param  SERVER_SOFTWARE    nginx/$nginx_version;
    fastcgi_param  REMOTE_ADDR        $remote_addr;
    fastcgi_param  REMOTE_PORT        $remote_port;
    fastcgi_param  SERVER_ADDR        $server_addr;
    fastcgi_param  SERVER_PORT        $server_port;
    fastcgi_param  SERVER_NAME        $server_name;
    fastcgi_param  REDIRECT_STATUS    200;
}

(Side note: I think this a problem with nginx, that you can't set an alias and the doc root at the same time. Weird, actually.)

Amazon EC2 ELB directing load to other instances and session stores

Yes, you can solve all those problems and more with the use of a centralised session store. Without knowing your application, it's impossible to point you at a definitive guide for implementing it (and it would be a Stack Overflow question anyway), but it's usually as simple as either setting an option (in frameworks like Rails) to writing a few lines of glue code that get called by the web framework and which connects to the store to store the details or retrieve them.

As far as what to use, I recommend Redis. While memcached would appear to do the trick, it has the unpleasant downside of requiring users to re-login whenever you need to restart your memcached instance(s). A good rule of thumb to follow in redundant systems is that no change to your infrastructure should show any user-visible symptoms. Redis, on the other hand, persists to disk, is blazingly fast both on update and retrieval, and has shown itself to be incredibly robust in the large-scale situations I've used it in.

Related Topic

Php – Limit redis connections when using PhpRedis as session store