Question

I had a running EC2 server with an elastic IP address that was happily running memcached and beanstalkd listening on the external IP at port 11211 and 11300 respectively. I took a AMI of the server to upgrade the size and when the server restarted, neither memcached nor beanstalkd were running. Troubling for memcached as this was init.d to restart but beanstalkd was run as daemon from command line.

However, after several hours, I can’t seem to figure out how to get them up and running again.

For memcached the config file reads:

# Default connection port is 11211
-p 11211

# Specify which IP address to listen on. The default is to listen on all IP addresses
-l <EXTERNAL IP ADDRESS>

When I try and run memcached as root from the command line:

memcached -d -m 1024 -u root -l <EXTERNAL IP ADDRESS> -v -p 11211

I get:

bind(): Cannot assign requested address
failed to listen on TCP port 11211: Cannot assign requested address

Yet when I look at netstat, nothing is bound to that port already:

netstat -ant | grep LIST
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:6379            0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:23              0.0.0.0:*               LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN

And if I grep the processlist, there is no other memcached running.

Iptables reports the following:

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:11300 state ESTABLISHED 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:11211 state ESTABLISHED 

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination 

The EC2 instance is using the same security group as the original server, so the required ports are open.

Finally, maybe a hint is that the ifconfig IP address is different to the elastic IP address. If I try listening on either the inet adds: Bcast: the memcached service runs and binds however I can’t seem to access memcached via the elastic IP.

I MUST be doing something stupid and obvious to you. Thanks for your help.

Answer 1

bind to 0.0.0.0 that should be public.