Open Stack

On 4/5/2017 3:09 PM, Sean Dague wrote:
> At the PTG clayg brought up an excellent question about what the
> expected flow was to restart a bunch of services in devstack after a
> code changes that impacts many of them (be it common code, or a
> library). People had created a bunch of various screen hacks over the
> years, but screen is flakey, and this is definitely not an ideal workflow.
>
> Over lunch clayg, clarkb, and I chatted about some options. Clark
> brought up the idea of doing systemd units for all of the services. A
> couple of weeks ago I decided it was time for me to understand systemd
> better anyway, and started playing around with what this might look like.
>
> The results landed here https://review.openstack.org/#/c/448323/.
> Documentation is here
> http://git.openstack.org/cgit/openstack-dev/devstack/tree/SYSTEMD.rst
>
> This is currently an opt in. All the services in base devstack however
> do work in this new model, and I and a few others have been using this
> mode the last week or so. It's honestly really great. Working on
> oslo.log changes it's now:
>
>     pip install -U .
>     sudo systemctl restart devstack@*
>
> And the change is now in all your services.
>
> There is also an oslo.log change for native systemd journal support
> (https://review.openstack.org/#/c/451525/), which once that has landed
> and been released, will let us do some neat query of the journal during
> development to see slices across services like this
> https://dague.net/2017/03/30/in-praise-of-systemd/.
>
> ACTION REQUIRED:
>
> If you maintain a devstack plugin that starts any services, now would be
> a great time to test to see if this works for them. The biggest issue is
> that the commands sent to run_process need to be absolute pathed.
>
>
> My hope is that by end of cycle this is going to be the default mode in
> devstack for *both* the gate and development, which eliminates one major
> difference between the two. I'm also hoping that we'll be able to keep
> and archive the journals from the runs, so you can download and query
> those directly. Especially once the oslo.log enhancements are there to
> add the additional structured data.
>
> 	-Sean
>

Cool. I've always wanted this. When I started on OpenStack I was used to 
using sysv-init files and service commands with RHEL and wasn't used to 
screen, so pretty much hated that in devstack but felt like I couldn't 
ever express that because all of the cool kids loved screen so much.

Well well well, how the tables have turned.

-- 

Thanks,

Matt