Ruby on rails can'；无法启动弹性搜索服务器

我正在尝试启动弹性搜索服务器，但出现以下错误

* Starting Elasticsearch Server 
sysctl: setting key "vm.max_map_count": Read-only file system

你知道怎么解决这个问题吗？我试着重新安装了整个东西，但没有用

下面是完整的操作

rs191919:~/workspace/sample_app (elastic-again) $ wget https://download.elasticsearch.org/elasticsearch/elasticsearch/elasticsearch-1.7.0.deb
--2016-03-11 17:21:12--  https://download.elasticsearch.org/elasticsearch/elasticsearch/elasticsearch-1.7.0.deb
Resolving download.elasticsearch.org (download.elasticsearch.org)... 23.21.221.132, 23.21.209.176, 23.23.251.246, ...
Connecting to download.elasticsearch.org (download.elasticsearch.org)|23.21.221.132|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 27320700 (26M) [application/x-debian-package]
Saving to: ‘elasticsearch-1.7.0.deb.1’

100%[==========================================================================================================>] 27,320,700  22.5MB/s   in 1.2s   

2016-03-11 17:21:14 (22.5 MB/s) - ‘elasticsearch-1.7.0.deb.1’ saved [27320700/27320700]

rs191919:~/workspace/sample_app (elastic-again) $ sudo dpkg -i elasticsearch-1.7.0.deb
Selecting previously unselected package elasticsearch.
(Reading database ... 125961 files and directories currently installed.)
Preparing to unpack elasticsearch-1.7.0.deb ...
Creating elasticsearch group... OK
Creating elasticsearch user... OK
Unpacking elasticsearch (1.7.0) ...
Setting up elasticsearch (1.7.0) ...
Processing triggers for ureadahead (0.100.0-16) ...
rs191919:~/workspace/sample_app (elastic-again) $ sudo update-rc.d elasticsearch defaults 95 10
 System start/stop links for /etc/init.d/elasticsearch already exist.
rs191919:~/workspace/sample_app (elastic-again) $ sudo /etc/init.d/elasticsearch start
 * Starting Elasticsearch Server                                                                                                                    sysctl: setting key "vm.max_map_count": Read-only file system
rs191919:~/workspace/sample_app (elastic-again) $ curl http://localhost:9200
curl: (7) Failed to connect to localhost port 9200: Connection refused
rs191919:~/workspace/sample_app (elastic-again) $ 

这有用吗？这有用吗？