无法连接到主机，Elasticsearch了吗？

Question

我已经重新安装了elasticsearch bundle，我在文档中进行了配置： fos_elastica.yml

fos_elastica:
clients:
    default: { host: localhost, port: 9200 }
indexes:
    Leimen:
        client: default
        types:
            Article:
                mappings:
                    id:
                        type: integer
                    date: ~
                    title: ~
                    author: ~
                    content: ~
                    email: ~
                persistence:
                    driver: orm
                    model: Leimen\SiteBundle\Entity\Article
                    finder: ~
                    provider: ~
                    listener: ~

当我运行fos:elastica:populate时 我收到此错误 [Elastica\Exception\Connection\HttpException] Couldn't connect to host, Elasticsearch down? 有人可以帮我吗？