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7.4 Cloud Considerations And Issues With Bright Cluster Manager
regular node or networked device). A special way of resolving nodes is
needed because the Amazon IP addresses are in the 10.0.0.0/8 network
space, which conflicts with some of the address spaces used by Bright
Cluster Manager.
There are no IP addresses defined by globalnet itself. Instead, a
node, with its domain defined by the globalnet network parameters,
has its name resolved by another network to an IP address. The resolution
is done by the nameserver on the head node for all nodes.
Resolution In And Out Of The Cloud
The networks, their addresses, their types, and their domains can be listed
from the network mode in cmsh:
[bright60->network]% list
Name (key)
Type
Netmask bits
------------ --------- ------------bmcnet
Internal 16
cloud
Cloud
8
externalnet External 16
globalnet
Global
0
ibnet
Internal 16
internalnet Internal 16
netmap
NetMap
16
us-east-1
Tunnel
16
Base address
------------10.148.0.0
10.0.0.0
10.2.0.0
0.0.0.0
10.149.0.0
10.141.0.0
172.31.0.0
172.21.0.0
Domain name
----------bmc.cluster
cloud.cluster
brightcomputing.com
cm.cluster
ib.cluster
eth.cluster
In a Type 1 network (section 2.3.6), the head node is connected to
internalnet. When a cloud service is configured, the head node is
also “connected” to the CMDaemon-managed NetMap “network”. It is
useful to think of NetMap as a special network, although it is actually
a network mapping from the cloud to internalnet. That is, it connects (maps) from the nodes in one or more cloud networks such as the
us-east-1 network provided by Amazon, to IP addresses provided by
netmap. The mapping is set up when a cloud extension is set up. With
this mapping, packets using NetMap go from the cloud, via an OpenVPN
connection to the NetMap IP address. Once the packets reach the OpenVPN interface for that address, which is actually on the head node, they
are forwarded via Shorewall’s IPtables rules to their destination nodes on
internalnet.
With default settings, nodes on the network internalnet and nodes
in a cloud network such as us-east-1 are both resolved with the help
of the cm.cluster domain defined in globalnet. For a cluster with
default settings and using the cloud network us-east-1, the resolution
of the IP address of 1. a regular node and 2. a regular cloud node, takes
place as follows:
1. node001, a regular node in the internalnet network, is resolved
for node001.cm.cluster to
(a) 10.141.0.1, when at the head node. The cluster manager assigns this address, which is on internalnet. It could also be
an ibnet address instead, such as 10.149.0.1, if InfiniBand
has been configured for the nodes instead of Ethernet.
(b) 172.31.0.1 when at the cloud director or regular cloud node.
The cluster manager assigns this address, which is a NetMap
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