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change isilon cluster default gateway
is there a way to change the cluster (not subnet) default gateway ?
#netstat -rn
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 10.250.14.254 UG 0 470738724 vlan1
10.250.14.0/24 link#9 UC 0 0 vlan1
10.250.14.72 00:50:56:9f:70:aa UHLW 0 26916 vlan1 1185
10.250.14.73 00:50:56:9f:70:b0 UHLW 0 2691 vlan1 1162
i need to change it to be the the same as the default GW for the Management subnet :
nyst0087-2# isi networks list subnets
Name Subnet Gateway:Prio SC Service Pools
--------------- ------------------ ------------------ --------------- -----
Internal-P 10.250.14.0/24 10.250.14.254:1 10.250.14.239 1
Internal-S 10.250.16.0/24 10.250.16.254:1 10.250.16.239 1
External 157.150.187.0/24 157.150.187.254:1 157.150.187.239 1
Management 10.250.25.0/24 10.250.25.254:1 10.250.25.239 2
Can I do this with changing Gateway priorities ?
Peter_Sero
1.2K Posts
1
March 14th, 2013 00:00
"The" default gateway can be set (modified) with
route change default
But beware, "the" default gateway is used when
any packets are being sent to an address OUTSIDE of the configured subnets.
If any of your client hosts are NOT directly located within your
Internal-P/S (which appear not to be the cluster's interconnects)
nor External subnets,
then any packets sent to those clients will be routed through the
new default gateway,
and therefore will leave the cluster through the "Management" subnet.
Is this really what you are aiming at?
(Probably you might want to choose the "External" subnet's gateway as default?)
Peter
bhalilov1
114 Posts
0
March 14th, 2013 07:00
Thanks Peter, the route change default gave an error :
#route change default 10.250.25.254
route: writing to routing socket: Address already in use
change net default: gateway 10.250.25.254: gateway uses the same route
But I tried changing the priorities of the gateways for the subnets (management to priority 1, all other to 2)
#isi networks list subnets
Name Subnet Gateway:Prio SC Service Pools
--------------- ------------------ ------------------ --------------- -----
Internal-P 10.250.14.0/24 10.250.14.254:2 10.250.14.239 1
Internal-S 10.250.16.0/24 10.250.16.254:2 10.250.16.239 1
External 157.150.187.0/24 157.150.187.254:2 157.150.187.239 1
Management 10.250.25.0/24 10.250.25.254:1 10.250.25.239 2
and that changed the cluster default gateway to what I wanted :
# netstat -rn
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 10.250.25.254 UG 0 991445 vlan3
I'm still confused how the subnet gateways and their priorities affect routing - I could not find any information about that.
cincystorage
467 Posts
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March 14th, 2013 08:00
By default each subnet will have a route for it's gateway and all traffic in that subnet will transverse that network... Otherwise each node has a default gateway.. gateway priority is really just a ranking of 1 (highest) to 10 (lowest) which specify's which subnet will be the default on a node with more than one subnet.
So if a node has just one subnet it will be the default. If a node as two, one with priority 5 and one with 8) the default with be the subnet with priority 5.
dynamox
2 Intern
2 Intern
•
20.4K Posts
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March 14th, 2013 20:00
Mark,
i also could not understand the purpose of default gateway for each subnet, did not make any sense to me because a node can only have one default gateway for the whole node. So what you are saying is that gateway priority controls which gateway becomes the default gateway ?
so if i were to change gateway priority for my dmz subnet my default gateway would change to 10.228.144.2 ?
Right now we have to set static routes to force traffic to certain subnets to go through specific interfaces.
Thanks
Peter_Sero
1.2K Posts
0
March 14th, 2013 21:00
That is was got me confused, too.
But Mark is right, and the Isilon online help makes it also clear:
Gateway priority: The priority of the subnet's gateway in relation to
other subnets' gateways for nodes that are assigned to more than one
subnet. Only one default gateway can be configured on each Isilon
node, but each subnet can have its own gateway. When a node belongs to
more than one subnet, this option allows you to define the preferable
default gateway. A value of 1 is the highest priority, with 10 being
the lowest priority.
The Unix way of "route add/change default...." clearly cannot work at the same time.
Peter
cincystorage
467 Posts
0
March 15th, 2013 01:00
Correct, if you changed your dmz subnet gateway priority to 10 (or anything lower than the other) it would become the default subnet.
Isilon documentation prior to 7.0 doesn't explain this concept very well, I'm told 7.0 is better but I haven't checked it out yet.
cincystorage
467 Posts
0
March 15th, 2013 07:00
You can use the FreeBSD method of changing a default route, but it is specific to a node and (I believe) not supported by EMC/Isilon. It is also not persistent through a reboot or other gateway/smartconnect changes..
bhalilov1
114 Posts
1
March 15th, 2013 14:00
Mark,
can you please explain what do you mean by "By default each subnet will have a route for it's gateway and all traffic in that subnet will transverse that network... "
cincystorage
467 Posts
0
March 15th, 2013 15:00
Sure. What I mean is that if you have two SmartConnect Zones/Subnets like you described:
nyst0087-2# isi networks list subnets
Name Subnet Gateway:Prio SC Service Pools
--------------- ------------------ ------------------ --------------- -----
Internal-P 10.250.14.0/24 10.250.14.254:1 10.250.14.239 1
Internal-S 10.250.16.0/24 10.250.16.254:1 10.250.16.239 1
External 157.150.187.0/24 157.150.187.254:1 157.150.187.239 1
Management 10.250.25.0/24 10.250.25.254:1 10.250.25.239 2
All traffic with destination in 10.250.14.0/24 will go out the interface's which make up Internal-P, as seen in the route bolded in the example below:
#netstat -rn
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 10.250.14.254 UG 0 470738724 vlan1
10.250.14.0/24 link#9 UC 0 0 vlan1
10.250.14.72 00:50:56:9f:70:aa UHLW 0 26916 vlan1 1185
10.250.14.73 00:50:56:9f:70:b0 UHLW 0 2691 vlan1 1162
dynamox
2 Intern
2 Intern
•
20.4K Posts
0
March 15th, 2013 15:00
but i don't understand why you need to specify a gateway, everything on that subnet will connect directly, it does not need to go to any routers. If it's not on that subnet it will hit your default gateway.
cincystorage
467 Posts
0
March 16th, 2013 04:00
You don't at all, my example was a bad one because I was in a hurry.
christopher_ime
2K Posts
0
March 16th, 2013 17:00
I've never had enough subnets to use any priority as high as 10, but I'm fairly certain it would likely be ignored with a priority that high.
I could be wrong. However, I will typically define a priority of 1 for the gateway that I want all else to be sent via (except of course for anything with a static route or on the same subnet of any defined within OneFS). Then all else will be 2 (or greater).
cincystorage
467 Posts
0
March 16th, 2013 19:00
The only time this is problematic is if a node doesn't have an interface in the priority 1 gateway subnet and several in the priority2 gateways - you never know which one will end up as default.
christopher_ime
2K Posts
0
March 16th, 2013 22:00
Very good point.
cincystorage
467 Posts
0
March 17th, 2013 15:00
My cluster has 5 subnets on them. Most nodes only have two subnets connected. One of the subnets is completely isolated, so it can only access traffic in the same subnet. This caused me two problems. On one node it was selected as the default gateway - so that node was dead in the water so to speak. The other was users connecting across the isolated subnet were unable to access via CIFS due to lack of access to a domain controller on a node with just that subnet.