Unable to start Elasticsearch

[ghost]

Elasticsearch version: 5.0

JVM version: openjdk version "1.8.0_111"

OS version: Amazon Linux AMI release 2014.03

I am using AWS m3.large instance. I have two elasticsearch nodes. For my data node(node-2) , When I started elasticsearch service with sudo service elasticsearch start

[2016-11-25T09:31:56,884][INFO ][o.e.b.BootstrapCheck     ] [node-2] bound or publishing to a non-loopback or non-link-local address, enforcing bootstrap checks
[2016-11-25T09:31:56,886][ERROR][o.e.b.Bootstrap          ] [node-2] node validation exception
bootstrap checks failed
max number of threads [1024] for user [elasticsearch] is too low, increase to at least [2048]

Then I edited file /usr/lib/systemd/system/elasticsearch.service and added line LimitNPROC=2048.

When I restarted service. I checked status: sudo service elasticsearch status
It returned ,
elasticsearch dead but subsys locked
In Log

[2016-11-25T09:50:32,138][INFO ][o.e.b.BootstrapCheck     ] [node-2] bound or publishing to a non-loopback or non-link-local address, enforcing bootstrap checks
[2016-11-25T09:50:32,140][ERROR][o.e.b.Bootstrap          ] [node-2] node validation exception
bootstrap checks failed
max number of threads [1024] for user [elasticsearch] is too low, increase to at least [2048]

Am I missing something ?

[clintongormley]

As far as I know, Amazon Linux AMI isn't using systemd, so you should be setting the nproc limit with ulimit or by configuring limits.conf

[ghost]

@clintongormley Thank you for response. I tried troubleshooting as you recommended. Got following things.
ulimit -u command returns:

[root@ip-address-subsys]# ulimit -u
2048

/etc/security/limits.conf

<domain>      <type>  <item>         <value>
#

#*               soft    core            0
#*               hard    rss             10000
#@student        hard    nproc           20
#@faculty        soft    nproc           20
#@faculty        hard    nproc           50
#ftp             hard    nproc           0
#@student        -       maxlogins       4
elasticsearch    hard    nproc           2048

[ghost]

I updated my Amazon Linux instance from 2014.03 to 2016.09. It worked for me. As I said it was running Amazon Linux 2014.03 previously.