Tried memcached_exporter (https://github.com/prometheus/memcached_exporter) on deployment-memc04.eqiad.wmflabs:
filippo@deployment-memc05:~$ curl -s localhost:9150/metrics | grep ^memca
memcached_commands_total{command="cas",status="badval"} 2262
memcached_commands_total{command="cas",status="hit"} 1.936389e+06
memcached_commands_total{command="cas",status="miss"} 21
memcached_commands_total{command="decr",status="hit"} 0
memcached_commands_total{command="decr",status="miss"} 0
memcached_commands_total{command="delete",status="hit"} 464711
memcached_commands_total{command="delete",status="miss"} 3771
memcached_commands_total{command="flush",status="hit"} 0
memcached_commands_total{command="get",status="hit"} 1.86302483e+08
memcached_commands_total{command="get",status="miss"} 1.57966743e+08
memcached_commands_total{command="incr",status="hit"} 116514
memcached_commands_total{command="incr",status="miss"} 204
memcached_commands_total{command="set",status="hit"} 8.488741e+06
memcached_commands_total{command="touch",status="hit"} 180469
memcached_commands_total{command="touch",status="miss"} 0
memcached_connections_total 197148
memcached_current_bytes 8.48931078e+08
memcached_current_connections 16
memcached_current_items 1.395356e+06
memcached_items_evicted_total 0
memcached_items_reclaimed_total 46462
memcached_items_total 1.0243271e+07
memcached_limit_bytes 3.145728e+09
memcached_read_bytes_total 2.9120185857e+10
memcached_up 1
memcached_uptime_seconds 1.1571958e+07
memcached_version{version="1.4.21"} 1
memcached_written_bytes_total 9.104556614e+10