Rails + Dalli memcache gem: DalliError: No server available

Question

Hi I'm having trouble setting up my Rails project on my server because apache keeps complaining

DalliError: No server available.

I installed memcached on my ubuntu machine, but it still doesn't work. My rails project also has config.cache_store = :dalli_store, 'localhost:11211', { :namespace => "production" } in environments/production.rb. How would I debug this?

My log shows before each request:

localhost:11211 failed (count: 6)
DalliError: No server available

telnet to 11211:

    root@s2:/usr/local/www/production/current/log# telnet localhost 11211
    Trying 127.0.1.1...
    telnet: Unable to connect to remote host: Connection refused

Answer 1

I had the same problem. First I installed memcached as a gem gem install memcached and got the error "DalliError: No server available"

Then I installed memcached by doing sudo apt-get install memcached. It works fine now.

Answer 2

If you're a Homebrew user:

brew install memcached

Check if the service is running:

brew services list

If not, start it:

brew services start memcached

Answer 3

It was because someone changed the /etc/hosts file to point 127.0.1.1 to localhost instead of 127.0.0.1. After changing that, memcached worked.

Answer 4

The accepted answer will probably solve the issue for 95% of people who are seeing this error, but in my case I found the issue to be far more fundamental:

From the server, I was unable to ping 127.0.0.1. This meant Dalli could not connect to the memcache server, which by default runs on 127.0.0.1:11211.

There are a number of things that could cause this issue, but the most likely is simply a missing network interface. If you run ifconfig, you should see something like this in the output:

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:15686 errors:0 dropped:0 overruns:0 frame:0
          TX packets:15686 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:23730314 (23.7 MB)  TX bytes:23730314 (23.7 MB)

If this is missing, ensure your /etc/network/interfaces file contains the following local interface definition:

auto lo
iface lo inet loopback

And then restart the networking service:

sudo /etc/init.d/networking restart

Answer 5

Use 127.0.0.1 instead of localhost should solve your (and mine) issue.

config.cache_store = :dalli_store, '127.0.0.1:11211', { namespace: 'production' }

Answer 6

In my case, I had recently updated memcached on the server, but the Ruby daemon had kept running through the upgrade. After simply restarting the Ruby daemon, the errors went away. (I also restarted mechached.)