Memcached failing after PHP upgrade

Question

I have been using memcached and I upgraded from PHP 5.4 to 5.6 and now it is failing to connect and store.

I have:

ini_set('session.save_handler', 'memcached');
ini_set('session.save_path', 'serverAddress:11211');
session_start();

I have also tried tcp:// before the server address, but no luck there.

In the error log, I am getting the following errors:

• PHP Warning: session_start(): Write of lock failed
• PHP Warning: session_start(): Unable to clear session lock record
• PHP Warning: Unknown: Failed to write session data (memcached). Please verify that the current setting of session.save_path is correct

I guess something changed in the versions of PHP. Any help is appreciated, thanks!

Note: I am using Amazon Elastic Beanstalk for the web server and ElastiCache for the memcached

What I Have Tried

1. Used a config file with:

   files:
     "/etc/php.d/setup.ini":
       mode: "000644"
       owner: root
       group: root
       source: https://s3.amazonaws.com/path/to/file.ini
   

Inside of the ini file is:

    [php]

    session.save_handler = memcached
    session.save_path = 'memcached.server.path.cache.amazonaws.com:11211'

2. I have tried using session_write_close()
3. I have tried using tcp:// before the server path
4. I have also tried using memcache instead of memcached as the handler.