Hi Adrian,
Please find responses inline
-Original Message-
From: Adrian Lewis [mailto:adr...@alsiconsulting.co.uk]
Sent: Friday, October 18, 2013 4:41 PM
To: users@cloudstack.apache.org
Subject: SSVM Public IP, NAT and L2/L3 connectivity
Hi All,
Still in the planning stages of deploying my first CS install and I have a
question about the SSVM and the apparent requirement for a public routable IP
address. From what I can gather, the only interaction that the SSVM has with
the internet is for downloading files from user or admin supplied URLs. Does
this mean that nothing actually makes inbound connections directly to it from
the internet and that it only ever makes outbound connections? If so, why does
it need a public IP?
[Sanjeev]: I could think of one scenario which is copying templates from one
zone to another zone where zones are at different geographical locations(i.e.
two zones are connected using internet).
Would it be possible to simply have a route to the internet via the management
network or to give it an IP from private network pool that has access to the
internet via some other NAT device?
[Sanjeev] As per the cloudstack terminology public ip does not mean that they
are real public IPs. They can be private IPs from which internet can be
accessed using other NAT device.
Secondly, I've seen some excellent slides from Geoff Higginbottom but I'm still
not quite sure whether the SSVM actually has four vNICs or whether it simply
needs access to four networks via a lesser number of vNICs. Can anyone clarify
how many vNICs each SSVM has and what the routing table looks like on the VM
itself, especially where the management server and secondary storage server are
on subnets accessible via a L3 hop and not directly attached to either the
hypervisor mgmt or SSVM vNICs (and these subnets aren't accessible by a default
route on the SSVM)?
[Sanjeev] It is necessary that there should be four vNICs on SSVM , each
belonging to only one network.
Management and Storage servers need not be on the same subnet. They should be
accessible via a L3 hop.
My main concern is the public IP requirement as I'm finding it very difficult
to get enough public IPs from my DC, especially where there doesn't appear to
be a reason for it. I can't simply get a nice big block of IPv4 like some other
CS users may be used to! I'm considering joining RIPE but this is not
especially cheap and doesn't seem to guarantee that I'd get an assignment of
IPv4 addresses anyway.
Confused,
Adrian
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