[Linux-cluster] Basic Active Active File Server

Wed Jun 23 17:47:23 UTC 2010

Hi All

thanks for all the advice guys, I will run through these tomorrow, (Pearl  
Jam last night, enough said!)

Jay

On Jun 23, 2010 8:32am, Kit Gerrits <kitgerrits at gmail.com> wrote:

> Hey Jay,

> I'm not at work at the moment, but this should get you started:

> 1/ The simplest test is to tell clustering to use broadcast instead of

> multicast.

> # In a single ESX server, you can use a host-only vSwitch for that.

> # Disable multicast by removing the multicast reference from the cluster

> configuration and restart the cluster

> You can check multicast traffic between nodes in 2 ways:

> 2/ dumping packets

> #relatively simple

> tcpdump -i ip multicast

> # I'm not sure (can't test from here), else try:

> tcpdump -i ether multicast

> # That should show multicast packets traveling over the interface to and

> from the hosts and the multicast IP

> 3/ ping tests

> # By enabling responses to broadcast pings in both Host O/S'es and pinging

> them on their multicast address:

> # http://kerneltrap.org/node/16225

> echo "0" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

> # find out the multicast IP of the cluster

> cman_tool status

> # Ex: Multicast addresses: 239.192.12.239

> # ping the multicast IP from each host

> ping -L 239.192.12.239

> #You should see ping replies.

> About DNS:

> Clustering will use the IP that the hostname resolves to.

> The interface that IP resolves to will be used for multicast traffic.

> If you need to use another interface, give the IP on that interface its  
> own

> hostname and put that in the cluster config.

> About 224.0.0.1

> I'm not sure, either.

> I will try It out at the office.

> Footnote:

> http://sourceware.org/cluster/doc/usage.txt

> Advanced Network Configuration

> ------------------------------

> * UDP Port

> CMAN uses UDP port 6809 by default. A different port number can be used  
> by:

> * Multicast

> CMAN can be configured to use multicast instead of broadcast (broadcast is

> used by default if no multicast parameters are given.) To configure

> multicast

> add one line under the section and another under the

> section:

> The multicast addresses must match and the address must be usable on the

> interface name given for the node.

> Regards,

> Kit

> -----Original Message-----

> From: Jason Fitzpatrick [mailto:jayfitzpatrick at gmail.com]

> Sent: dinsdag 22 juni 2010 10:40

> To: Kit Gerrits

> Cc: linux clustering

> Subject: Re: [Linux-cluster] Basic Active Active File Server

> Hi Kit..

> Awesome and all as I am when it comes to computers, networking is a  
> serious

> weak point ;0)

> How would I go about checking if multicast traffic is making it between  
> the

> two nodes, they are now hosted of the same ESX server and therefore only

> hitting the virtual switch in the ESX and should not have to traverse our

> network at all.

> I will review the ESX switch config and DNS (I have a horrible feeling  
> that

> the DNS gremlins are responsible, but am pretty sure that this should not

> affect Multicast)

> Also the multicast address that should be used, I am using 244.0.0.1

> which I believe is The All Hosts multicast group that contains all

> systems on the same network segment, but am not a 100% sure if this is the

> correct setting.

> Thanks again

> Jay

> On 22 June 2010 09:12, Kit Gerrits kitgerrits at gmail.com> wrote:

> >

> > Keep in mind that multicast requires a multicast router to handle the

> > traffic.

> > Mere Layer2 connectivity is not enough.

> >

> > If broadcast does work, that might be your problem.

> >

> > Kit

> >

> > -----Original Message-----

> > From: linux-cluster-bounces at redhat.com

> > [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Jason

> > Fitzpatrick

> > Sent: maandag 21 juni 2010 18:14

> > To: linux clustering

> > Subject: Re: [Linux-cluster] Basic Active Active File Server

> >

> > Hi..

> >

> > I have tried both multicast and broadcast to no avail, as above I am

> > moving the systems to the same ESX to try and rule out the networking

> > end of things, I have not tried the tcpdump but was running wireshark

> > in an attempt to do the same as you recommended

> >

> > Jay

> >

> > On 21 June 2010 16:49, Kaloyan Kovachev kkovachev at varna.net> wrote:

> >> Hi,

> >> On Mon, 21 Jun 2010 16:07:34 +0100, Jason Fitzpatrick

> >> jayfitzpatrick at gmail.com> wrote:

> >>> Hi all

> >>>

> >>> I am having no end of trouble getting a basic Active Active Cluster

> >>> working. at the moment it is in test / proof of concept and has

> >>> manual fencing in place but I cannot for the life of me get the 2

> >>> nodes to join to the one cluster (they both report joined in

> >>> crm_tool status but only to a local clustered instance if that makes

> >>> any

> >>> sence)

> >>>

> >>> I have tried to use luci and system-config-cluster to get this up

> >>> and running and have been at it over a week, the network guys swear

> >>> that there is nothing blocking multicast traffic between them and

> >>> the firewalls have been disabled (they are on the same VLAN but

> >>> connected to different switches) servers have been rebuilt and have

> >>> RHEL 5.5 installed

> >>>

> >>

> >> your problem is the multicast traffic - check with tcpdump if it is

> >> comming to the other server at all (network) and if it is, then

> >> doublecheck the firewall.

> >> alternatively you may try using broadcast instead of multicast

> >>

> >>> Shared Storage is being provided by an Active Active DRBD setup

> >>> (tested and working)

> >>>

> >>> I have attached a copy of my cluster.conf

> >>>

> >>> Thanks in advance

> >>>

> >>> Jay

> >>>

> >>> --

> >>>

> >>> "The only difference between saints and sinners is that every saint

> >>> has a past while every sinner has a future. "

> >>> - Oscar Wilde

> >>

> >> --

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> >

> >

> >

> > --

> >

> > "The only difference between saints and sinners is that every saint

> > has a past while every sinner has a future. "

> > - Oscar Wilde

> >

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