Mailing-List: contact user-help@zookeeper.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@zookeeper.apache.org
Received-SPF: pass (nike.apache.org: domain of ted.dunning@gmail.com
 designates 209.85.160.41 as permitted sender)
References: <316f0048.f2f7.13f9d583b11.Coremail.qhwj2006@126.com>
 <D96AFB7A-11ED-41A3-B882-6519F934FF34@gmail.com>
Mime-Version: 1.0 (1.0)
In-Reply-To: <D96AFB7A-11ED-41A3-B882-6519F934FF34@gmail.com>
Content-Type: text/plain;
	charset=utf-8
Content-Transfer-Encoding: quoted-printable
Message-Id: <1EC6F53E-C1B0-4DFD-BF24-AC3B961CED98@gmail.com>
Cc: "user@zookeeper.apache.org" <user@zookeeper.apache.org>
From: Ted Dunning <ted.dunning@gmail.com>
Subject: Re: Is it a good idea to embed ZK in a product application ?
Date: Mon, 1 Jul 2013 20:37:47 -0700
To: "user@zookeeper.apache.org" <user@zookeeper.apache.org>

Embedding zk in a product is a fine thing.  Embedding zk in an application i=
s (in my estimation) a bad idea.  The problem is that you generally want to c=
oordinate all the way down to zero, especially in upgrade situations.  Combi=
ning the uptime constraints of zk with those of your app is bad strategy. =20=


As a concrete example, suppose that you need one or more copy if your softwa=
re to run and you are running it on 6 machines.  Should your zk quorum inclu=
de all 6 machines?  I think not. =20

Now what happens if you want to upgrade?  It is plausible that your app will=
 work with only or copy running but you probably would want enough to handle=
 current load during a rolling upgrade.  Should that requirement be combined=
 with the need to preserve a zk quorum?  What if you have zk on 3 machines a=
nd you want to upgrade all three of those in step 1 of a rolling upgrade.  D=
o you really want to make that impossible?

Sent from my iPhone

On Jul 1, 2013, at 20:22, Kai Lu <lukai1984@gmail.com> wrote:

> A lot of applications in big companies had done that already.
>=20
> On Jul 1, 2013, at 8:06 PM, =E5=90=B4=E9=9D=96 <qhwj2006@126.com> wrote:
>=20
>> Hi all:
>>=20
>>=20
>>  Recently my company want use zk to manage our cluster( For node manageme=
nt and HA). But someone in my team want to embed the ZK in our product appli=
cation.  But somehow I always feel very odd to embed ZK in.
>>  Here my question are : Is it a  good idea to embed ZK in a product appli=
cation ?
>>     And dose it work fine  in product mode (like overflow memory and othe=
r problems )?
>>=20
>>=20
>>=20
>> thank you !
>>=20
>>=20