Hi Carsten,

That's a good question. We haven't built anything specifically to support
0-downtime for the DEAs, but we have some upcoming changes to make the etcd
used by etcd-metric-server, routing-api, all loggregator components, and
HM9k also switch to TLS. This would affect all the metron agents colocated
on all the VMs, and we're building out a component to support a 0-downtime
transition.

This work is currently in flight:
https://www.pivotaltracker.com/epic/show/2566951

You could apply this concept to consul:

* create a new secure (TLS) consul cluster
* replace the existing consul cluster (don't change the job name or IPs,
just what processes it runs) with an HTTP proxy that proxies requests to
the secure cluster
* roll out the new IPs and TLS credentials to all clients of the consul
cluster
* after that deploy is done, nothing should be talking to the HTTP proxy,
and you can simply delete that job.

Best,
Amit

On Fri, Jun 24, 2016 at 8:46 AM, Long Nguyen <long.nguyen11288(a)gmail.com>
wrote:

Hi there!

We found that if you monit stop all the consul nodes before upgrading and
adding ssl. The deployment should upgrade without any issues.

Thanks,
Long

On June 23, 2016 at 11:56:04 AM, Hiort, Carsten, Springer DE (
carsten.hiort(a)springer.com) wrote:

Hi,

CF v234 enforces the use of SSL for Consul. We are currently wondering if
there is a supposed upgrade path.
When you switch to SSL and the Consul cluster get’s upgraded all machines
that are not yet upgraded will be blind with respect to service discovery/
DNS through Consul. This particularly affects the DEAs as they are not able
to figure out where to get the droplets from when staging causing a 500
when cf pushing. I did already try deploying the Certs on 231 with
require_ssl=false but then setting require_ssl true or upgrading to v234+
will still rest in this situation.
Any thoughts highly appreciated!


Thanks,

Carsten

---

Carsten Hiort
Platform Engineer
Platform Engineering

SpringerNature
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