[ClusterLabs] Antw: Announcing hawk-apiserver, now in ClusterLabs

[Kristoffer Grönlund]

Ulrich Windl  <Ulrich.Windl at rz.uni-regensburg.de> writes:

> Hello!
>
> I'd like to comment as an "old" SuSE customer:
> I'm amazed that lighttpd is dropped in favor of some new go application:
> SuSE now has a base system that needs (correct me if I'm wrong): shell, perl,
> python, java, go, ruby, ...?
>

Oh, that list is a lot longer, and this is not the first go project to
make it into SLE.

> Maybe each programmer has his favorite. Personally I also learned quite a lot
> of languages (and even editors), but most being equivalent, you'll have to
> decide whether it makes sense to start using still another language (go in this
> case). Especially i'm afraid of single-vendor languages...

TBH I am more sceptical about languages designed by committee ;)

Cheers,
Kristoffer

>
> Regards,
> Ulrich
>
>>>> Kristoffer Grönlund <kgronlund at suse.com> schrieb am 12.02.2019 um 20:00
> in
> Nachricht <87mun0g7c9.fsf at suse.com>:
>> Hello everyone,
>> 
>> I just wanted to send out an email about the hawk-apiserver project
>> which was moved into the ClusterLabs organization on Github today. This
>> project is used by us at SUSE for Hawk in our latest releases already,
>> and is also available in openSUSE for use with Hawk. However, I am
>> hoping that it can prove to be useful more generally, not just for Hawk
>> but for other projects that may want to integrate with Pacemaker using
>> the C API, and also to show what is possible when using the API.
>> 
>> To describe the hawk-apiserver briefly, I'll start by describing the use
>> case it was designed to cover: Previously, we were using lighttpd as the
>> web server for Hawk (a Ruby on Rails application), but a while ago the
>> maintainers of lighttpd decided that since Hawk was the only user of
>> this project in SLE, they would like to remove it from the next
>> release. This left Apache as the web server available to us, which has
>> some interesting issues for Hawk: Mainly, we expect people to run apache
>> as a resource in the cluster which might result in a confusing mix of
>> processes on the systems.
>> 
>> At the same time, I had started looking at Go and discovered how easy it
>> was to write a basic proxying web server in Go. So, as an experiment I
>> decided to see if I could replace the use of lighttpd with a custom web
>> server written in Go. Turns out the answer was yes! Once we had our own
>> web server, I discovered new things we could do with it. So here are
>> some of the other unique features in hawk-apiserver now:
>> 
>> * SSL certificate termination, and automatic detection and redirection
>>   from HTTP to HTTPS *on the same port*: Hawk runs on port 7630, and if
>>   someone accesses that port via HTTP, they will get a redirect to the
>>   same port but on HTTPS. It's magic.
>> 
>> * Persistent connection to Pacemaker via the C API, enabling instant
>>   change notification to the web frontend. From the point of view of the
>>   web frontend, this is a long-lived connection which completes when
>>   something changes in the CIB. On the backend side, it uses goroutines
>>   to enable thousands of such long-lived connections with minimal
>>   overhead.
>> 
>> * Optional exposure of the CIB as a REST API. Right now this is somewhat
>>   primitive, but we are working on making this a more fully featured
>>   API.
>> 
>> * Configurable static file serving routes (serve images on /img from
>>   /srv/http/images for example).
>> 
>> * Configurable proxying of subroutes to other web applications.
>> 
>> The URL to the project is https://github.com/ClusterLabs/hawk-apiserver,
>> I hope you will find it useful. Comments, issues and contributions are
>> of course more than welcome.
>> 
>> One final note: hawk-apiserver uses a project called go-pacemaker
>> located at https://github.com/krig/go-pacemaker. I indend to transfer
>> this to ClusterLabs as well. go-pacemaker is still somewhat rough around
>> the edges, and our plan is to work on the C API of pacemaker to make
>> using and exposing it via Go easier, as well as moving functionality
>> from crm_mon into the C API so that status information can be made
>> available in a more convenient format via the API as well.
>> 
>> -- 
>> // Kristoffer Grönlund
>> // kgronlund at suse.com 
>> _______________________________________________
>> Users mailing list: Users at clusterlabs.org 
>> https://lists.clusterlabs.org/mailman/listinfo/users 
>> 
>> Project Home: http://www.clusterlabs.org 
>> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf 
>> Bugs: http://bugs.clusterlabs.org 
>
>
>
> _______________________________________________
> Users mailing list: Users at clusterlabs.org
> https://lists.clusterlabs.org/mailman/listinfo/users
>
> Project Home: http://www.clusterlabs.org
> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> Bugs: http://bugs.clusterlabs.org

-- 
// Kristoffer Grönlund
// kgronlund at suse.com