View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0004469 | Taler | deployment and operations | public | 2016-04-24 18:01 | 2016-04-28 22:16 |
| Reporter | Florian Dold | Assigned To | Florian Dold | ||
| Priority | normal | Severity | feature | Reproducibility | have not tried |
| Status | closed | Resolution | fixed | ||
| Product Version | 0.0 | ||||
| Target Version | 0.0 | Fixed in Version | 0.0 | ||
| Summary | 0004469: blue-green deployments for demo.taler.net | ||||
| Description | Right now, when we update demo.taler.net we have two problems: - downtime during the actual update - when something goes terribly wrong, we can't go back Thus we should adopt green-blue deployments, where we have two copies of the demo environment. While updating one of them (e.g. green.demo.taler.net) the other one (e.g. blue.demo.taler.net) still serves traffic. When we're done updating, we switch over to green.demo.taler.net. If something goes horribly wrong, we simply switch back to blue.demo.taler.net while we're fixing the problem (or we could decide to just postpone the upgrade). | ||||
| Tags | No tags attached. | ||||
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(see http://martinfowler.com/bliki/BlueGreenDeployment.html) |
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This is trivial to implement in theory, but (the free version of) NGINX does not support dynamic upstream reconfiguration. So we'll have to find some other component to do that for us. |
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Since we're using uWSGI anyway, we could use uWSGI for dynamic upstream configuration, since it has decent support for it: http://uwsgi-docs.readthedocs.org/en/latest/Fastrouter.html http://uwsgi-docs.readthedocs.org/en/latest/InternalRouting.html#http uWSGI has lots of different ways to do dynamic reconfiguration, but the simplest is just a directory with hostname->upstream mappings. |
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Alternatively we could just use a per-user nginx instance (that can be reconfigured without touching the root nxing). Though this is less convenient, since we always need to restart the nginx process, while uWSGI supports dynamic switching. |
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There's a /home/{demo,test]/sockets directory now. This links to one of /home/{demo,test}-{blue,green}/sockets. The socket directory contains the uwsgi/http sockets for merchant, exchange, donations, blog, landing. Pointing {test,demo}.taler.net to either blue or green is done by simply updating this symlink. |
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Note that we're not using any active switching / load balancing, nginx simply points to the unix-domain sockets in the symlinked directory. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2016-04-24 18:01 | Florian Dold | New Issue | |
| 2016-04-24 18:03 | Florian Dold | Assigned To | => Marcello Stanisci |
| 2016-04-24 18:03 | Florian Dold | Severity | minor => feature |
| 2016-04-24 18:03 | Florian Dold | Status | new => assigned |
| 2016-04-24 18:04 | Florian Dold | Note Added: 0010549 | |
| 2016-04-24 18:50 | Florian Dold | Note Added: 0010550 | |
| 2016-04-24 20:37 | Florian Dold | Note Added: 0010551 | |
| 2016-04-24 20:43 | Florian Dold | Note Added: 0010552 | |
| 2016-04-24 20:55 | Florian Dold | Note Edited: 0010552 | |
| 2016-04-24 23:38 | Florian Dold | Description Updated | |
| 2016-04-27 01:54 | Florian Dold | Note Added: 0010562 | |
| 2016-04-27 01:54 | Florian Dold | Status | assigned => resolved |
| 2016-04-27 01:54 | Florian Dold | Resolution | open => fixed |
| 2016-04-27 01:54 | Florian Dold | Assigned To | Marcello Stanisci => Florian Dold |
| 2016-04-27 01:55 | Florian Dold | Note Added: 0010563 | |
| 2016-04-28 22:16 | Christian Grothoff | Status | resolved => closed |
| 2016-04-28 22:16 | Christian Grothoff | Product Version | => 0.0 |
| 2016-04-28 22:16 | Christian Grothoff | Fixed in Version | => 0.0 |
| 2016-04-28 22:16 | Christian Grothoff | Target Version | => 0.0 |
