cloudstack-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Geoff Higginbottom <>
Subject Re: mgmt VM access to VPC
Date Fri, 08 Feb 2013 03:31:41 GMT
Hi Alex,

I've actually been working on a similar problem myself.  If I understand your solution, it's
to use a shared network connected to each tier of the VPC.  If this is correct, surely you
are 'breaking' the VPC model as you have now connected each Tier to a common shared network,
meaning they are no longer isolated.

What we tested today was to map a unique network to each Tier, each with a unique VLAN and
CIDR, using a custom network offering providing only DHCP service.  These networks were connected
to a Firewall which enables a management network to connect to each tier, but prevents the
Tiers communicating directly.

As you point out, VMs have to be deployed using the API not the GUI, and I can confirm this
works in CloudStack 4.0.

We did have to create 'shared' networks in order to create a VM connected to both a VPC Tier
and another Network (it does not work with an Isolated Network) but as the Network is only
connected to VMs belonging to one Tier, we did not compromise the VPC isolation model.

One final step was to add a persistent route to each VM, ensuring traffic destined for the
'management' network was routed over the secondary network and not the default network which
is connected to the VPC.  This route can be added manually, or by using the 'user data' feature
to tell each VM which Gateway to use (it's different for every Tier so cannot be baked into
the template)


Geoff Higginbottom
CTO / Cloud Architect

D: +44(0)20 3603 0542<tel:+442036030542> | S: +44(0)20 3603 0540<tel:+442036030540>
| M: +44(0)7968161581<tel:+447968161581><> |

ShapeBlue Ltd, 53 Chandos Place, Covent Garden, London, WC2N 4HS

Find out about our free webinars on Citrix Cloud Technologies<>

On 7 Feb 2013, at 19:51, "Alex Heneveld" <<>>

An update on this.  It seems there are currently 4 viable options for solving this VPC mgmt
access problem, summarised below. Thanks Chip and Alex (minor questions in-line).

> We're trying to set up a VPC/nTier-App such that a single VM (call it a
> management node) outside the VPC has ssh access to the VM's inside the
> VPC.  (And to do this for multiple VPC's, same mgmt node.) What's the
> best way to implement this?

1) Shared-network solution -- this is what we've done and I'm pleased to say it works!  (Alex,
although this isn't exposed in the GUI, the API call to attach an additional network to VPC
nodes works fine -- in cloudplatform 3.0.5 at least)

2) "DIY" remote access VPN [Chip's suggestion] -- Chip, if I understand your suggestion correctly
it's basically that we roll-our-own VPN on a VM in the VPC w/ ip-sec gateway to enable remote-access
("road warrior") VPN'ing, since this isn't available out of the box for VPC's (as per [1])

3) Port-forwarding on extra VPC public IP -- managing these assignments is tedious (as Chip
notes) but it is not as bad as it sounds; we've had to do this before, in LXC-land where containers
are isolated.  it has benefit over #2 of not needing a dedicated VPN endpoint VM in the VPC,
and over #1 not attaching a free-for-all mgmt network; but it isn't elegant or fun.

4) s2s VPN [Alex Huang's suggestion] - i think this is a nice option if you already have the
beefy hardware (Cisco / Juniper) that this requires, based on the wiki [2] at least -- is
that right?  although it would be inefficient if that hardware isn't local (b/c all traffic
is routed through the remote gateway) and also note there is a question in the wiki whether
it will work between zones (but I see no reason why it wouldn't?)

The mgmt VM can be in the same zone here (re Chip's question).  If the mgmt VM is in a different
zone then #1 doesn't work (not unless you use it to set up a proxy then use one of the other
techniques to connect in to it).

It will be nice when #754 is implemented [1] as that seems better than any of these.  :)

I hope this is useful to anyone else needing to do this.  Any comments or corrections welcome.
 And happy to share the code if that's of interest.



On 06/02/2013 17:23, Alex Huang wrote:
-----Original Message-----
From: Chip Childers []
Sent: Wednesday, February 06, 2013 7:43 AM
Subject: Re: mgmt VM access to VPC

On Wed, Feb 06, 2013 at 02:23:08AM +0000, Alex Heneveld wrote:

We're trying to set up a VPC/nTier-App such that a single VM (call it a
management node) outside the VPC has ssh access to the VM's inside the
VPC.  (And to do this for multiple VPC's, same mgmt node.)  What's the
best way to implement this?

It seems like #754 [1] would be the right way to go about this when
available (is that right?) but already there are a few things we could
do now:

- set up an extra public IP on each tier with careful port forwarding
and ACL restricted to the mgmt node
- use an s2s vpn where the other "site" is just the mgmt node
- use a shared network, seems supported based on #748 [2] (but this
would break isolation?)

Any thoughts on these or others?



Is this "other VM" going to be in a different zone?

This seems like you would have to consider it as being a completely
different entity from the VPC that it will be connecting into.  With
that being the case, you're best off setting up an IP sec tunnel
into the VPC from that VM.  I don't think you'll want to manage a bunch
of port forwarding rules for each VM in the VPC.
+1  I don't think shared network is supported by VPC at this point so s2s vpn should be the
best way to go.


ShapeBlue provides a range of strategic and technical consulting and implementation services
to help IT Service Providers and Enterprises to build a true IaaS compute cloud. ShapeBlue's
expertise, combined with CloudStack technology, allows IT Service Providers and Enterprises
to deliver true, utility based, IaaS to the customer or end-user.


This email and any attachments to it may be confidential and are intended solely for the use
of the individual to whom it is addressed. Any views or opinions expressed are solely those
of the author and do not necessarily represent those of Shape Blue Ltd. If you are not the
intended recipient of this email, you must neither take any action based upon its contents,
nor copy or show it to anyone. Please contact the sender if you believe you have received
this email in error. Shape Blue Ltd is a company incorporated in England & Wales.

  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message