Unable to use memcache for session storage

[anishnagaraj]

I am moving away from using cookies to a server-side for my application's session storage because of the size of the session object. Our application uses lua-resty-openidc integrated with Azure AD and I believe the security code generated by Azure is too large and thus the size of the session is also huge.

Environment

lua-resty-openidc version -1.7.3
OpenID Connect provider -Azure AD

Expected behaviour

We have to choose Memcache for the session storage. I put in all the configurations as mentioned by lua-resty-session but the creation of session fails.

Actual behaviour

The session is not created successfully. The error I see in the logs are as follows,

	/usr/local/share/lua/5.1/resty/session.lua: in function 'new'
	/usr/local/share/lua/5.1/resty/session.lua:571: in function 'open'
	/usr/local/share/lua/5.1/resty/session.lua:611: in function 'start'
	access_by_lua(lb.conf:225):2: in function <access_by_lua(lb.conf:225):1>, client: 10.244.1.5, server: xyz-dev.eo.tools, request: "GET /browse/homepage HTTP/1.1", host: "xyz-dev.eo.tools" 

I would expect that the exceptions provide more specific details.

My nginx.conf file

user www-data;
worker_processes auto;
error_log stderr warn;
pid /run/nginx/nginx.pid;

# Load dynamic modules. See /usr/share/nginx/README.dynamic.
include /etc/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main_timed  '$remote_addr - $remote_user [$time_local] "$request" '
                            '$status $body_bytes_sent "$http_referer" '
                            '"$http_user_agent" "$http_x_forwarded_for" '
                            '$request_time $upstream_response_time $pipe $upstream_cache_status';

    access_log /dev/stdout main_timed;
    error_log /dev/stderr notice;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites/*.conf;

    lua_shared_dict sessions       1m;
    lua_shared_dict sessions_locks 1m;

    server {
        set $session_storage memcache;

        set $session_memcache_prefix           sessions;
        set $session_memcache_connect_timeout  1000; # (in milliseconds)
        set $session_memcache_send_timeout     1000; # (in milliseconds)
        set $session_memcache_read_timeout     1000; # (in milliseconds)
        set $session_memcache_socket           unix:///var/run/memcached/memcached.sock;
        set $session_memcache_host             aks-nodepool1-42857599-vmss000000;
        set $session_memcache_port             5000;
        set $session_memcache_uselocking       on;
        set $session_memcache_spinlockwait     150;  # (in milliseconds)
        set $session_memcache_maxlockwait      30;   # (in seconds)
        set $session_memcache_pool_name        sessions;
        set $session_memcache_pool_timeout     1000; # (in milliseconds)
        set $session_memcache_pool_size        10;
        set $session_memcache_pool_backlog     10;
        
    }

}

Could somebody help me find out what I am missing!