Mailing-List: contact dev-help@brooklyn.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@brooklyn.apache.org
From: Svetoslav Neykov <svetoslav.neykov@cloudsoftcorp.com>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: quoted-printable
Mime-Version: 1.0 (Mac OS X Mail 10.2 \(3259\))
Subject: [BROOKLYN-436] - Thoughts on making the URL an HA member is available
 at available
Message-Id: <56835424-B600-4133-9A06-17F9357309CB@cloudsoftcorp.com>
Date: Fri, 24 Feb 2017 14:19:45 +0200
To: dev@brooklyn.apache.org
archived-at: Fri, 24 Feb 2017 12:19:54 -0000


Summary of the issue: Each HA member node publishes a URL it's available =
at in the persisted state. For the Karaf build no value is set.
Available at: https://issues.apache.org/jira/browse/BROOKLYN-436

When fixing the issue I'm wondering whether we should stick to the =
existing behaviour for inferring the URL or change it a bit. TL;DR - =
should we use the public IP of the machines instead?

Current steps for building the URL are:
  * Get the hostname from "--publicAddress" command line option if set
  * Get the hostname from "--bindAddress" command line option if set and =
not "0.0.0.0"
  * Get the hostname of the local machine (can be overriden in config =
with "brooklyn.location.localhost.address" system property)
  * Combine the above with the port the web server is configured to run =
at (and the protocol)

The default behaviour from above is to set the URL to the local address =
of the machine.

There are a couple of common uses of the value:
  1) Clients using the REST API will use it to find what's the MASTER of =
the cluster by going to any member.
  2) Users going to a non-master web UI will be offered the option to be =
redirected to the MASTER

1) Could need either the public or the private IP, depending on where =
the HA members are relative to the client using them.
2) Most often need the public URL, but sometimes the local address might =
be preferred - for example when connecting by VPN to the member's =
network.

By public IP here I mean what IP the machine is visible to the world =
with. The machine might not have a public IP assigned at all, and be =
NATted to the internet instead.

Another use case could be to use the hostname from the URL to let the =
MASTER  configure networking access for the standby servers.

Given the above I don't think a one size fits all solution is possible. =
I think we should keep the existing URL using the local address and =
provide a second value with the public URL as well. This will let =
clients pick the one (they think) is appropriate.

Svet.