Re: [Vserver] support for multicast?

Sat, 26 Nov 2005 13:52:55 -0800

Sorry I am joining this late. Also sorry that I am top posting :(. But we do the tomcat multicast clustering here and it was just as you had attempted. We run legacy mode and have : 

IPROOT="eth0:192.168.129.234 228.0.0.4"
S_CAPS="CAP_KILL CAP_SETGID CAP_SETUID CAP_SETPCAP CAP_NET_BROADCAST CAP_SYS_NICE CAP_NET_ADMIN" 


Probably added too many capabilities, but security is not the issue, 
just being able to run in a vserver :).



Yes on start the vserver spews out stuff, but the multicast was needed 
in the conf file.


Hope this helps,
JES


Drew Lippolt wrote:



i've upgraded to:

kernel 2.6.12.5
vs 2.0

i'm still getting the same problem as before.

and believe i have narrowed the multicast problem.


strangely, i can SEND/BROADCAST no problem.  i say strange since the  
creation of the mutlicast group is more complicated than simply  
consuming the broadcast.


running inside the vserver, the multicast client never sees traffic.


i can run the broadcaster inside the vserver and talk to adjacent  
receivers on other physical boxes.




but when i run mutlicast test code for RECEIVING multicast inside a  
vserver strace shows:



[EMAIL PROTECTED]:~/try2$ strace ./multirec 224.0.0.9 9210

execve("./multirec", ["./multirec", "224.0.0.9", "9210"], [/* 13 vars  
*/]) = 0

uname({sys="Linux", node="v237", ...})  = 0
brk(0)                                  = 0x804a000

old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,  
-1, 0) = 0xb7fb7000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or  
directory)
open("/etc/ld.so.preload", O_RDONLY)    = -1 ENOENT (No such file or  
directory)

open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=8305, ...}) = 0
old_mmap(NULL, 8305, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7fb4000
close(3)                                = 0

access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or  
directory)

open("/lib/tls/libc.so.6", O_RDONLY)    = 3

read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0`Z\1\000"...,  
512) = 512

fstat64(3, {st_mode=S_IFREG|0755, st_size=1254468, ...}) = 0

old_mmap(NULL, 1264780, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) =  
0xb7e7f000
old_mmap(0xb7fa9000, 36864, PROT_READ|PROT_WRITE, MAP_PRIVATE| 
MAP_FIXED, 3, 0x129000) = 0xb7fa9000
old_mmap(0xb7fb2000, 7308, PROT_READ|PROT_WRITE, MAP_PRIVATE| 
MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7fb2000

close(3)                                = 0

old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,  
-1, 0) = 0xb7e7e000
set_thread_area({entry_number:-1 -> 6, base_addr:0xb7e7e460, limit: 
1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,  
seg_not_present:0, useable:1}) = 0

munmap(0xb7fb4000, 8305)                = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP) = 3

bind(3, {sa_family=AF_INET, sin_port=htons(9210), sin_addr=inet_addr 
("0.0.0.0")}, 16) = 0

setsockopt(3, SOL_IP, IP_ADD_MEMBERSHIP, "\340\0\0\t\0\0\0\0", 8) = 0
recvfrom(3,  <unfinished ...>


when running receiver code OUTSIDE the vserver (in the base host)

app2:/vservers/v237/home/mcaster/try2# strace ./multirec 224.0.0.9 9210

execve("./multirec", ["./multirec", "224.0.0.9", "9210"], [/* 17 vars  
*/]) = 0

uname({sys="Linux", node="app2.moverotech.com", ...}) = 0
brk(0)                                  = 0x804a000

old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,  
-1, 0) = 0xb7ef2000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or  
directory)
open("/etc/ld.so.preload", O_RDONLY)    = -1 ENOENT (No such file or  
directory)

open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=10985, ...}) = 0
old_mmap(NULL, 10985, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7eef000
close(3)                                = 0

access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or  
directory)

open("/lib/tls/libc.so.6", O_RDONLY)    = 3

read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0`Z\1\000"...,  
512) = 512

fstat64(3, {st_mode=S_IFREG|0755, st_size=1254468, ...}) = 0

old_mmap(NULL, 1264780, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) =  
0xb7dba000
old_mmap(0xb7ee4000, 36864, PROT_READ|PROT_WRITE, MAP_PRIVATE| 
MAP_FIXED, 3, 0x129000) = 0xb7ee4000
old_mmap(0xb7eed000, 7308, PROT_READ|PROT_WRITE, MAP_PRIVATE| 
MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7eed000

close(3)                                = 0

old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,  
-1, 0) = 0xb7db9000
set_thread_area({entry_number:-1 -> 6, base_addr:0xb7db9460, limit: 
1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,  
seg_not_present:0, useable:1}) = 0

munmap(0xb7eef000, 10985)               = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP) = 3

bind(3, {sa_family=AF_INET, sin_port=htons(9210), sin_addr=inet_addr 
("0.0.0.0")}, 16) = 0

setsockopt(3, SOL_IP, IP_ADD_MEMBERSHIP, "\340\0\0\t\0\0\0\0", 8) = 0
recvfrom(3, "testtest", 255, 0, NULL, NULL) = 8
time(NULL)                              = 1132896911
brk(0)                                  = 0x804a000
brk(0x806b000)                          = 0x806b000
brk(0)                                  = 0x806b000
open("/etc/localtime", O_RDONLY)        = 4
fstat64(4, {st_mode=S_IFREG|0644, st_size=1279, ...}) = 0

mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,  
-1, 0) = 0xb7ef1000
read(4, "TZif\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\5\0\0\0\5\0"...,  
4096) = 1279

close(4)                                = 0
munmap(0xb7ef1000, 4096)                = 0
fstat64(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(136, 3), ...}) = 0

mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,  
-1, 0) = 0xb7ef1000
write(1, "Time Received: Thu Nov 24 23:35:"..., 51Time Received: Thu  
Nov 24 23:35:11 2005 : testtest

) = 51
recvfrom(3, "testtest", 255, 0, NULL, NULL) = 8
time(NULL)                              = 1132896914

write(1, "Time Received: Thu Nov 24 23:35:"..., 51Time Received: Thu  
Nov 24 23:35:14 2005 : testtest

) = 51



they look identical up to the point where the vserver never actually  
gets a recvfrom(3, "testtest", 255, 0, NULL, NULL) = 8


thoughts?

<drew>



On Nov 16, 2005, at 5:55 AM, Drew Lippolt wrote:



On Nov 15, 2005, at 7:11 PM, Herbert Poetzl wrote:


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:

[EMAIL PROTECTED] opt]# cat /proc/version
Linux version 2.4.30-vs1.2.10 ([EMAIL PROTECTED]) (gcc  version

3.2.3 20030502 (Red Hat Linux 3.2.3-52)) #1 Wed Aug 10 01:27:44  
CDT 2005


[EMAIL PROTECTED] 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?



tried a few different ways.

IPROOT="192.168.1.237 228.0.0.4"
IPROOT="192.168.1.237 228.0.0.4/224.0.0.0"





*  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 ...





the following are true, with NET_ADMIN, NET_BROADCAST, NET_RAW,  
SYS_ADMIN all set



*  clustering tool's test case suggests i'm SENDING multicast  
traffic, but not RECEIVING


*  tcpdump suggests i'm SENDING but not RECIEVING


* i can ping the multicast address from the shell while the app  
server is running, but not when its not running


*  adding routes doesn't seem to effect it at all





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 ...





i'm down for whatever.  i have a good testbed.  i just missed you  on 
irc tonight.  will try againtomorrow.





best,
Herbert

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




i'm planning on moving to 2.6 anyway.  we can chat about the 2.1.x  
stuff.


<snip>






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