elasticsearch报错[WARN ][bootstrap ] Unable to lock JVM Memory: error=12,reason=Cannot allocate memory，解决

早上在服务器上安装elasticsearch集群，在其中的一台上面安装好elasticsearch之后安装了一些插件，其中一个插件是marvel，结果可能是新版本不支持这个插件，就没有安装成功，也就索性没管，安装了head和kopf插件，安装完之后改了一下配置文件

systemctl restart elasticssearch重启，结果却报错了，报错如下：

[2017-03-15 14:58:42,874][WARN ][bootstrap                ] Unable to lock JVM Memory: error=12,reason=Cannot allocate memory
[2017-03-15 14:58:42,874][WARN ][bootstrap                ] This can result in part of the JVM being swapped out.
[2017-03-15 14:58:42,874][WARN ][bootstrap                ] Increase RLIMIT_MEMLOCK, soft limit: 65536, hard limit: 65536
[2017-03-15 14:58:42,874][WARN ][bootstrap                ] These can be adjusted by modifying /etc/security/limits.conf, for example: 
        # allow user 'elasticsearch' mlockall
        elasticsearch soft memlock unlimited
        elasticsearch hard memlock unlimited
[2017-03-15 14:58:42,874][WARN ][bootstrap                ] If you are logged in interactively, you will have to re-login for the new limits to take effect.
[2017-03-15 14:58:43,084][INFO ][node                     ] [linux-node-1] version[2.4.4], pid[3869], build[fcbb46d/2017-01-03T11:33:16Z]
[2017-03-15 14:58:43,084][INFO ][node                     ] [linux-node-1] initializing ...
[2017-03-15 14:58:43,832][INFO ][plugins                  ] [linux-node-1] modules [reindex, lang-expression, lang-groovy], plugins [head, marvel-agent, kopf], sites [kopf, head]
[2017-03-15 14:58:43,878][INFO ][env                      ] [linux-node-1] using [1] data paths, mounts [[/ (rootfs)]], net usable_space [15gb], net total_space [19gb], spins? [unknown], types [rootfs]
[2017-03-15 14:58:43,879][INFO ][env                      ] [linux-node-1] heap size [1015.6mb], compressed ordinary object pointers [true]
[2017-03-15 14:58:43,943][ERROR][bootstrap                ] Exception
java.lang.IllegalStateException: marvel plugin requires the license plugin to be installed
        at org.elasticsearch.marvel.license.LicenseModule.verifyLicensePlugin(LicenseModule.java:37)
        at org.elasticsearch.marvel.license.LicenseModule.<init>(LicenseModule.java:25)
        at org.elasticsearch.marvel.MarvelPlugin.nodeModules(MarvelPlugin.java:89)
        at org.elasticsearch.plugins.PluginsService.nodeModules(PluginsService.java:263)
        at org.elasticsearch.node.Node.<init>(Node.java:179)
        at org.elasticsearch.node.Node.<init>(Node.java:140)
        at org.elasticsearch.node.NodeBuilder.build(NodeBuilder.java:143)
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:194)
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:286)
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:45)

发现下面爆了个licence错误，说 marvel plugin requires the license plugin to be installed，于是想到那个插件没有安装成功，去plugin目录下面把marvel-agent目录移除了，重启就正常了