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Zookeeper, mail # user - Use DNS to distribute list of servers, not client config


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Re: Use DNS to distribute list of servers, not client config
Vishal Kher 2011-05-25, 18:22
Hi,

I am curious to know how many actually use this feature.

This feature assumes:
a) highly available DNS
b) ability to make DNS entries

It will be nice to know if products using ZK have the ability of
making entries in the DNS servers.  I am under the impression that it
would be very difficult, especially for products that are not deployed
in your IT environment.

It would be possible to satisfy the above assumptions by having
ZOOKEEPER-1031 resolved and running a query server (DNS/web/etc) on the ZK
leader.  It will be nice to know if users would like to have this
feature.
Thanks.
-Vishal

On Mon, May 23, 2011 at 8:43 AM, Fournier, Camille F. [Tech] <
[EMAIL PROTECTED]> wrote:

> This is already supported in the zk client.
>
> Cheers,
>
> C
>
>
> ----- Original Message -----
> From: Paul Sutter <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> Sent: Mon May 23 01:38:20 2011
> Subject: Use DNS to distribute list of servers, not client config
>
> A single DNS name can map to several IP addresses, and this complete list
> of
> addresses is available to any DNS client.
>
> If the Zookeeper client were to interpret DNS names so as to allow multiple
> IP addresses from one DNS name, a single DNS name in the Zookeeper client
> config to represent an arbitrary list of servers, so that the list of
> servers could be changed centrally with no client config changes.
>
> This is a widely supported standard feature of DNS. For example, we use
> this
> at Quantcast to power the second most requested URL on the Internet, and we
> get nice clean random distribution of client requests to IP addresses
> despite all the weird DNS servers, proxies, and browsers out there.
>
> Here's an example where edge.quantserve.com translates into 8 different
> server IPs. Web browsers select one of these at random. Zookeeper should do
> the same to simplify client configurations.
>
> $ nslookup edge.quantserve.com
> Server: 192.168.1.1
> Address: 192.168.1.1#53
>
> Non-authoritative answer:
> edge.quantserve.com canonical name = map-js.quantserve.com.akadns.net.
> map-js.quantserve.com.akadns.net canonical name > anycast-americas.quantserve.com.akadns.net.
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.58
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.63
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.37
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.39
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.23
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.46
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.24
> Name: anycast-americas.quantserve.com.akadns.net
> Address: 64.94.107.20
>