AFAIK, TrustedFilter is using a sort of cache to cache the trusted state, which is designed to solve the performance issue mentioned here.
My thoughts for deprecating it are: #1. We already have customers here in China who are using that filter. How are they going to do upgrade in the future? #2. Dependency should not be a reason to deprecate a module in OpenStack, Nova is not a stand-alone module, and it depends on various technologies and libraries. Intel is setting up the third party CI for TCP/OAT in Liberty, which is to address the concerns mentioned in the thread. And also, OAT is an open source project which is being maintained as the long-term strategy. For the situation that a host gets compromised, OAT checks trusted or untrusted from the start point of boot/reboot, it is hard for OAT to detect whether a host gets compromised when it is running, I don't know how to detect that without the filter? Back to Michael's question, the process of the verification is done by software automatically when a host boots or reboots, will that be an overhead for the admin to have a separate job? Thanks. -- Shane -----Original Message----- From: Michael Still [mailto:mi...@stillhq.com] Sent: Wednesday, June 24, 2015 7:49 AM To: OpenStack Development Mailing List (not for usage questions) Subject: Re: [openstack-dev] [nova] How to properly detect and fence a compromised host (and why I dislike TrustedFilter) I agree. I feel like this is another example of functionality which is trivially implemented outside nova, and where it works much better if we don't do it. Couldn't an admin just have a cron job which verifies hosts, and then adds them to a compromised-hosts host aggregate if they're owned? I assume without testing it that you can migrate instances _out_ of a host aggregate you can't boot in? Michael On Tue, Jun 23, 2015 at 8:41 PM, Sylvain Bauza <sba...@redhat.com> wrote: > Hi team, > > Some discussion occurred over IRC about a bug which was publicly open > related to TrustedFilter [1] I want to take the opportunity for > raising my concerns about that specific filter, why I dislike it and > how I think we could improve the situation - and clarify everyone's > thoughts) > > The current situation is that way : Nova only checks if one host is > compromised only when the scheduler is called, ie. only when > booting/migrating/evacuating/unshelving an instance (well, not exactly > all the evacuate/live-migrate cases, but let's not discuss about that > now). When the request goes in the scheduler, all the hosts are > checked against all the enabled filters and the TrustedFilter is > making an external HTTP(S) call to the Attestation API service (not > handled by Nova) for *each host* to see if the host is valid (not > compromised) or not. > > To be clear, that's the only in-tree scheduler filter which explicitly > does an external call to a separate service that Nova is not managing. > I can see at least 3 reasons for thinking about why it's bad : > > #1 : that's a terrible bottleneck for performance, because we're > IO-blocking N times given N hosts (we're even not multiplexing the > HTTP requests) > #2 : all the filters are checking an internal Nova state for the host > (called HostState) but that the TrustedFilter, which means that > conceptually we defer the decision to a 3rd-party engine > #3 : that Attestation API services becomes a de facto dependency for > Nova (since it's an in-tree filter) while it's not listed as a > dependency and thus not gated. > > > All of these reasons could be acceptable if that would cover the > exposed usecase given in [1] (ie. I want to make sure that if my host > gets compromised, my instances will not be running on that host) but > that just doesn't work, due to the situation I mentioned above. > > So, given that, here are my thoughts : > a/ if a host gets compromised, we can just disable its service to > prevent its election as a valid destination host. There is no need for > a specialised filter. > b/ if a host is compromised, we can assume that the instances have to > resurrect elsewhere, ie. we can call a nova evacuate c/ checking if an > host is compromised or not is not a Nova responsibility since it's > already perfectly done by [2] > > In other words, I'm considering that "security" usecase as something > analog as the HA usecase [3] where we need a 3rd-party tool > responsible for periodically checking the state of the hosts, and if > compromised then call the Nova API for fencing the host and evacuating the > compromised instances. > > Given that, I'm proposing to deprecate TrustedFilter and explictly > mention to drop it from in-tree in a later cycle > https://review.openstack.org/194592 > > Thoughts ? > -Sylvain > > > > [1] https://bugs.launchpad.net/nova/+bug/1456228 > [2] https://github.com/OpenAttestation/OpenAttestation > [3] > http://blog.russellbryant.net/2014/10/15/openstack-instance-ha-proposa > l/ > > > ______________________________________________________________________ > ____ OpenStack Development Mailing List (not for usage questions) > Unsubscribe: > openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev -- Rackspace Australia __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev