ubuntu17.04安装elasticsearch后启动报错YAMLException

ubuntu17.04成功安装elasticsearch最新的稳定版后，启动时报YAMLException，请大神们帮忙看一下：
/usr/share/elasticsearch/bin$ ./elasticsearch
Exception in thread "main" java.lang.NoClassDefFoundError: org/elasticsearch/common/jackson/dataformat/yaml/snakeyaml/error/YAMLException
at org.elasticsearch.common.jackson.dataformat.yaml.YAMLFactory._createParser(YAMLFactory.java:426)
at org.elasticsearch.common.jackson.dataformat.yaml.YAMLFactory.createParser(YAMLFactory.java:327)
at org.elasticsearch.common.xcontent.yaml.YamlXContent.createParser(YamlXContent.java:90)
at org.elasticsearch.common.settings.loader.XContentSettingsLoader.load(XContentSettingsLoader.java:45)
at org.elasticsearch.common.settings.loader.YamlSettingsLoader.load(YamlSettingsLoader.java:46)
at org.elasticsearch.common.settings.ImmutableSettings$Builder.loadFromStream(ImmutableSettings.java:982)
at org.elasticsearch.common.settings.ImmutableSettings$Builder.loadFromUrl(ImmutableSettings.java:969)
at org.elasticsearch.node.internal.InternalSettingsPreparer.prepareSettings(InternalSettingsPreparer.java:110)
at org.elasticsearch.bootstrap.Bootstrap.initialSettings(Bootstrap.java:144)
at org.elasticsearch.bootstrap.Bootstrap.main(Bootstrap.java:215)
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:32)
Caused by: java.lang.ClassNotFoundException: org.elasticsearch.common.jackson.dataformat.yaml.snakeyaml.error.YAMLException
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 11 more