[jboss-dev] Public IP address used by JBoss AS

[Bela Ban]

Brian Stansberry wrote:
> Putting this on jboss-dev, as my guess is 3/4 of the work is 
> discussing a bit. Particularly interested in hearing from Mr. Boot, ALR.
>
> What we're talking about is https://jira.jboss.org/browse/JBAS-8001 
> which is a proposal to allow some standard aliases for IP addresses 
> that the AS would resolve to something meaningful on the local 
> machine. The purpose is to make it easier to use the AS in a cloud 
> environment where the user can't know addresses in advance. Proposed 
> aliases are:
>
> - GLOBAL: picks a global (public) address
> - SITE_LOCAL: an address starting with 192.168.x.x or 10.0.x.x
> - LINK_LOCAL: a link local address, ie. starting with 169.x.x.x or 
> 254.x.x.x
> - NON_LOOPBACK: picks any non-loopback address
> - LOOPBACK: picks a loopback address
>
> My current take on this is if we did it for AS 6 we'd implement it in 
> the org.jboss.Main class.[1] Basically we'd alter the command line 
> processing for -b, -Djboss.bind.address and -Djgroups.bind_addr to 
> detect the above aliases and replace with the appropriate value.
>
> IMO we would *not* allow these values as a general configuration 
> option, e.g. in a -jboss-beans.xml:
>
> <!-- Not supported -->
> <property name="bindAddress">PUBLIC</property>

-100 IMO: a user may want to define an address based on some criteria, 
so the above makes perfect sense ! I can even envisage that we support 
something like this later:

<property name="bindAddress">192.168.*,274.2.*,SITE_LOCAL</property>,

which means that we should try to pick a site local address starting 
with 192.168, if not found a global IP address starting with 274.*, and 
if still not found, go and grab any site local address.

All of this logic can be centralized (in JGroups it is in 1 place) and 
used everywhere.


> That would be too much work, since as soon as you allow it one 
> configuration document you should allow it everywhere.

Yes, but again, if this is centralized, this should be simple. In 
JGroups, processing of all IP addresses (IpAddress, InetAddress, or 
lists thereof) is done in 1 place (via annotations).

> The weakness of only using it via Main's command line processing is if 
> people only want to use, for example, PUBLIC, in one spot, not as a 
> global value like -b. If we want to help with that, perhaps we could 
> use a system property namespace, and have Main check for properties in 
> that namespace and resolve them. For example:
>
> -Djboss.bind.address.myfoosocket=PUBLIC
>
> My instinct though is to *not* support that. First, to me there is no 
> clear use case. Second, in AS 7 I'm pretty sure we are going to want 
> to move away from system properties as a core way of configuring the 
> AS, so let's not add new system property-based features in 6.

IMO, GLOBAL, SITE_LOCAL, LOOPBACK etc are *IP addresses*, as good as the 
dotted decimal notation (192.168.1.5) ! They are simply resolved at boot 
time, versus statically.

If we allow for these keywords to be used with -b, then it would be 
weird for users not to be able to use them in XML config files or as 
system properties !

-- 
Bela Ban
Lead JGroups / Clustering Team
JBoss