DockerfileでElasticsearchのpluginをインストールできない。

DockerfileでElasticsearchのpluginをインストールしようとすると、下記エラーが発生します。プロキシが入っている環境です。
最初のFROMのところはうまく行っているので、Dockerfile上でElasticsearchのプラグインのプロキシ設定ができていないのかなと思います。
原因がわかる方、教えてください。
よろしくお願いいたします。

Step N/N : RUN bin/elasticsearch-plugin install someplugin
---> Running in xxxxxxxxxxxx
Exception in thread "main" java.net.ConnectException: Connection refused (Connection refused)
at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
at java.base/java.net.Socket.connect(Socket.java:591)
at java.base/sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:285)
at java.base/sun.security.ssl.BaseSSLSocketImpl.connect(BaseSSLSocketImpl.java:173)
at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:182)
at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:474)
at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:569)
at java.base/sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:265)
at java.base/sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:372)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:191)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1181)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1075)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:177)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:163)
at org.elasticsearch.plugins.InstallPluginCommand.urlExists(InstallPluginCommand.java:352)
at org.elasticsearch.plugins.InstallPluginCommand.getElasticUrl(InstallPluginCommand.java:314)
at org.elasticsearch.plugins.InstallPluginCommand.download(InstallPluginCommand.java:254)
at org.elasticsearch.plugins.InstallPluginCommand.execute(InstallPluginCommand.java:229)
at org.elasticsearch.plugins.InstallPluginCommand.execute(InstallPluginCommand.java:216)
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86)
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124)
at org.elasticsearch.cli.MultiCommand.execute(MultiCommand.java:77)
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124)
at org.elasticsearch.cli.Command.main(Command.java:90)
at org.elasticsearch.plugins.PluginCli.main(PluginCli.java:47)