From common-issues-return-158366-archive-asf-public=cust-asf.ponee.io@hadoop.apache.org Fri Sep 21 20:22:04 2018 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx-eu-01.ponee.io (Postfix) with SMTP id 1B665180671 for ; Fri, 21 Sep 2018 20:22:03 +0200 (CEST) Received: (qmail 6973 invoked by uid 500); 21 Sep 2018 18:22:03 -0000 Mailing-List: contact common-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Delivered-To: mailing list common-issues@hadoop.apache.org Received: (qmail 6962 invoked by uid 99); 21 Sep 2018 18:22:03 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd4-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 21 Sep 2018 18:22:03 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd4-us-west.apache.org (ASF Mail Server at spamd4-us-west.apache.org) with ESMTP id 8B65BC1358 for ; Fri, 21 Sep 2018 18:22:02 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd4-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -110.301 X-Spam-Level: X-Spam-Status: No, score=-110.301 tagged_above=-999 required=6.31 tests=[ENV_AND_HDR_SPF_MATCH=-0.5, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, USER_IN_DEF_SPF_WL=-7.5, USER_IN_WHITELIST=-100] autolearn=disabled Received: from mx1-lw-us.apache.org ([10.40.0.8]) by localhost (spamd4-us-west.apache.org [10.40.0.11]) (amavisd-new, port 10024) with ESMTP id PweYQ_DWlkgj for ; Fri, 21 Sep 2018 18:22:01 +0000 (UTC) Received: from mailrelay1-us-west.apache.org (mailrelay1-us-west.apache.org [209.188.14.139]) by mx1-lw-us.apache.org (ASF Mail Server at mx1-lw-us.apache.org) with ESMTP id 71D375F3CE for ; Fri, 21 Sep 2018 18:22:01 +0000 (UTC) Received: from jira-lw-us.apache.org (unknown [207.244.88.139]) by mailrelay1-us-west.apache.org (ASF Mail Server at mailrelay1-us-west.apache.org) with ESMTP id 01523E0E5D for ; Fri, 21 Sep 2018 18:22:01 +0000 (UTC) Received: from jira-lw-us.apache.org (localhost [127.0.0.1]) by jira-lw-us.apache.org (ASF Mail Server at jira-lw-us.apache.org) with ESMTP id BCA3D23FA1 for ; Fri, 21 Sep 2018 18:22:00 +0000 (UTC) Date: Fri, 21 Sep 2018 18:22:00 +0000 (UTC) From: "Anu Engineer (JIRA)" To: common-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HADOOP-15774) Discovery of HA servers MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/HADOOP-15774?page=3Dcom.atlassi= an.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=3D16= 624003#comment-16624003 ]=20 Anu Engineer commented on HADOOP-15774: --------------------------------------- {quote}[~anu] any thoughts on the general approach? I'm not very familiar w= ith the OZone architecture; do you guys also need to specify servers manual= ly? {quote} [~elgoiri] Thanks for posting the design docs. My apologies for the delayed= response, been busy with Ozone Alpha release. I have proposed the same idea a couple of times internally. Each time it go= t shot down because of the issue that [~stevel@apache.org] is referring to. {quote}Being part of the YARN may bring some weird dependencies (HDFS->YARN= ), any ideas here? Should it be move to a separate place? Maybe parts? {quote} The most important concern was always HDFS taking a dependency on YARN. It = creates a cyclical dependency. Ozone needs and plans to build something very similar to this, but our thou= ght has been to create something like this in SCM. For Hadoop and also from Ozone perspective, The consideration for such a se= rvice should be slightly different. It is possible for someone to run a clu= ster without HDFS or even without YARN. A Discovery service should be indep= endent of these specific services. If we are planning to make this a Hadoop level discovery service we should = probably build this independent of all other services. If possible, even in= dependent of ZooKeeper. Then this service can be the bootup service, and all other services includi= ng HDFS, YARN and even Zookeeper can use this service to discover endpoints= . Many services need to find the address of zookeeper too. If this service can be built independent of all other services, Ozone can c= ertainly use this, and we don't need to reinvent discovery. Another critical issue that Ozone struggles with this the issue of config c= hanges =E2=80=93 for example, in the HA case if a server fails and a new se= rver is added Datanodes need to be told of that. Ozone solves it by reading these changes from SCM, not only config via Hear= tbeat. But this problem is more generic, in the sense that there is a class of con= figuration changes that need to be pushed to all entities in the cluster. W= e have been thinking about building a discovery and config store for Ozone. > Discovery of HA servers > ----------------------- > > Key: HADOOP-15774 > URL: https://issues.apache.org/jira/browse/HADOOP-15774 > Project: Hadoop Common > Issue Type: New Feature > Reporter: =C3=8D=C3=B1igo Goiri > Priority: Major > Attachments: Discovery Service.pdf > > > Currently, Hadoop relies on configuration files to specify the servers. > This requires maintaining these configuration files and propagating the c= hanges. > Hadoop should have a framework to provide discovery. > For example, in HDFS, we could define the Namenodes in a shared location = and the DNs would use the framework to find the Namenodes. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscribe@hadoop.apache.org For additional commands, e-mail: common-issues-help@hadoop.apache.org