Re: [Vserver] support for multicast?

From: Herbert Poetzl <herbert_at_13thfloor.at>
Date: Wed 16 Nov 2005 - 01:11:28 GMT
Message-ID: <20051116011128.GB26875@MAIL.13thfloor.at>

On Mon, Nov 14, 2005 at 03:09:32AM -0600, Drew Lippolt wrote:
>
> QUESTION: what is the current story with multicast support for both
> sending and receiving multicast traffic?
>
> BACKGROUND:
>
> trying to get tomcat clustering working in vserver.
>
> http://tomcat.apache.org/tomcat-5.5-doc/cluster-howto.html
>
> DETAILS:
>
> [root@app2 opt]# cat /proc/version
> Linux version 2.4.30-vs1.2.10 (root@app1.moverotech.com) (gcc version
> 3.2.3 20030502 (Red Hat Linux 3.2.3-52)) #1 Wed Aug 10 01:27:44 CDT 2005
>
> [root@app2 opt]# grep MULTICAST /boot/config-2.4.30-vs1.2.10
> CONFIG_IP_MULTICAST=y
>
> tomcat 5.5.12
>
> i'm running debian sarge vservers on redhat enterprise linux 3.0
> boxes at rackspace, using a stock kernel.org kernel with required
> tweaks for my hardware this is a production environment which has
> been supporting many apps beautifully for 3 months.
>
> the basic idea is that i have multiple app layer boxes, which i want
> to distribute tomcat clusters. single instance of tomcat, running in
> a single vserver, per real host, per application. so if i have 3
> apps, on 3 real servers, i'd have 9 total vservers across 3
> clusters. i'm not even getting that far. my test setup is 2 real
> hosts, each with one vserver with an 'out of the box' tomcat cluster
> config. the tomcat instances aren't finding each other.
>
> the stacktraces i'm getting on tomcat --shutdown-- are as follows,
> which doesn't look all that interesting, its in code looking for
> incoming connections on a tcp port, which never arrive, since the
> mcast conversation never happens (ReplicationListener.java:130):
>
> SEVERE: Unable to process request in ReplicationListener
> java.nio.channels.ClosedSelectorException
> at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:
> 55)
> at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:70)
> at org.apache.catalina.cluster.tcp.ReplicationListener.listen
> (ReplicationListener.java:130)
> at org.apache.catalina.cluster.tcp.ClusterReceiverBase.run
> (ClusterReceiverBase.java:394)
> at java.lang.Thread.run(Thread.java:534)
>
>
> THINGS I"VE TRIED:
>
> * add multicast ip to IPROOT. this just causes barf messages at
> vserver startup
>
> Starting the virtual server v208
> Server v208 is not running
> SIOCSIFADDR: Invalid argument
> SIOCSIFFLAGS: Cannot assign requested address
> SIOCSIFNETMASK: Cannot assign requested address
> SIOCGIFADDR: Cannot assign requested address
> SIOCSIFBROADCAST: Cannot assign requested address
> SIOCSIFBRDADDR: Cannot assign requested address
> SIOCSIFFLAGS: Cannot assign requested address
> ipv4root is now 192.168.1.208 228.0.0.4

how did you add it?

> * enabled NET_ADMIN and NET_BROADCAST. this offers no change

well, NET_ADMIN is what you probably need for
multicasting, NET_BROADCAST should suffice for
multicast reception ...

if you are interested in 'improving' multicast
capabilities in a safe way, and willing to do
some testing, please contact me on the IRC
channel ...

best,
Herbert

PS: will require switching to 2.6 kernel and
recent devel version (2.1.x)

> * googling for multicast setup on vserver. almost zero info.
>
> http://www.paul.sladen.org/vserver/archives/200205/0090.html (no
> response)
>
> http://list.linux-vserver.org/archive/vserver/msg08171.html (some
> progress, no resolution)
>
> * searching for multicast in vserver irc logs, almost zero info.
>
> as usual, thanks in advance for any information.
>
> take care,
>
> <drew>
> _______________________________________________
> Vserver mailing list
> Vserver@list.linux-vserver.org
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Received on Wed Nov 16 01:11:49 2005

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