[openstack-dev] [swift] Use FQDN in Ring files instead of "ip"

Osanai, Hisashi osanai.hisashi at jp.fujitsu.com
Thu Jul 24 01:27:20 UTC 2014


I would like to discuss this topic more deeply.

I understand we need to prepare DNS systems and add a lot of operational 
complexity and burden to use the DNS system when we use FQDN in Ring files.

However I think most datacenter have DNS systems to manage network resources 
such as ip addresses and hostnames and it is centralized management.
And you already pointed out that we can get benefit to use FQDN in Ring files 
with some scenarios. 

A scenarios: Corruption of a storage node

IP case:
One storage node corrupted when swift uses IPs in Ring files. An operator removes 
the node from swift system using ring-builder command and keeping the node for 
further investigation. Then the operator tries to add new storage node with 
different ip address. In this case swift rebalance all objects.

FQDN case:
One storage node corrupted when swift uses FQDN in Ring files. An operator prepares 
new storage node with difference ip address then changes info in DNS systems with 
the ip address. In this case swift copy objects that related to the node.

If above understanding is true, it is better to have ability for using FQDN in Ring 
files in addition to ip addresses. What do you think?

On Thursday, July 24, 2014 12:55 AM, John Dickinson wrote:

> However, note that until now, we've intentionally kept it as just IP
> addresses since using hostnames adds a lot of operational complexity and
> burden. I realize that hostnames may be preferred in some cases, but this
> places a very large strain on DNS systems. So basically, it's a question
> of do we add the feature, knowing that most people who use it will in
> fact be making their lives more difficult, or do we keep it out, knowing
> that we won't be serving those who actually require the feature.

Best Regards,
Hisashi Osanai



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