[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: Node names in an OpenShift installation



Thanks, Luke, Dmitri,

I think I'm beginning to understand. Please correct me if I'm wrong.

For every app foo-bar.domain.com the local DNS server for OpenShift maintains an entry pointing the domain to the IP address of the Node server on which the gear is hosted. When a client sshes to xyz foo-bar domain com the DNS server returns the correct IP of the node server. Hence ALL nodes need to have the same credentials to prevent ssh from complaining.

A few questions

1) I'm confused by the overloading of the term hostname in the docs. 

When a node is added with oo-register-dns -h node -d example.com -n 10.4.59.y -k ${keyfile}, the -h parameter is the fqdn of the node or it can be any name ? Also can an fqdn be specified in -n or does it need to be an externally routable IP address (for EC2) ?

2) How does an app hosted on multiple gears work ?

3) How does the system deal with DNS propagation delay ? Say a gear is moved from node 1 to node 2, a client could still attempt to connect to node 1. What prevents the ssh from succeeding on node 1 ?

Thanks,
Arunabha


On Wed, Nov 6, 2013 at 9:07 AM, Dmitri Pal <dpal redhat com> wrote:
On 11/05/2013 10:13 PM, Luke Meyer wrote:
> No, it doesn't mean they have the same hostname. It means they have the same host keys.
>
> Git users access their gears via ssh to the gear hostname. That doesn't change even if the gear moves to a new host. What ssh complains about is when the host keys change.

May be this can help:
http://cloud-mechanic.blogspot.com/2013/10/diversion-kerberos-freeipa-in-aws-ec2.html

>
> ----- Original Message -----
> From: "Arunabha Ghosh" <arunabha gh gmail com>
> To: dev lists openshift redhat com
> Sent: Tuesday, November 5, 2013 9:09:16 PM
> Subject: Node names in an OpenShift installation
>
>
>
> Hi,
> Going through the puppet installation documentation for OpenShift here, I came across this sentence.
>
> "All node hosts should identify as the same host, so that when gears are moved between hosts, ssh and git don’t give developers spurious warnings about the host keys changing."
>
>
> Does this mean that even if I have, say a hundred node hosts in my deployment, each node must have the same hostname (like node.mydomain.com ) ?
>
>
> Thanks,
> Arunabha
> _______________________________________________
> dev mailing list
> dev lists openshift redhat com
> http://lists.openshift.redhat.com/openshiftmm/listinfo/dev
>
> _______________________________________________
> dev mailing list
> dev lists openshift redhat com
> http://lists.openshift.redhat.com/openshiftmm/listinfo/dev
>
>


--
Thank you,
Dmitri Pal

Sr. Engineering Manager for IdM portfolio
Red Hat Inc.


-------------------------------
Looking to carve out IT costs?
www.redhat.com/carveoutcosts/





[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]