more discussions on fabric alternatives

howto/fabric.md

@@ -333,6 +333,13 @@ configuration management interface "creeping in" next to Puppet. The
 intention of this deployment is to have the absolute minimal amount of
 code needed to do things Puppet cannot do, not to replace it.
 
+One major problem with Fabric is that it creates pretty terrible code:
+it is basically a glorified Makefile, because we cannot actually run
+Python code on the remote servers directly. (Well, we could, but we'd
+first need to upload the code and call it a shell command, so it is
+not real IPC.) In that sense, Mitogen is a real eye-opener and
+game-changer.
+
 ## Cost
 
 Time and labor.
@@ -501,29 +508,46 @@ mitogen only.
 
 The biggest advantage of transiliance is that it builds on top of
 mitogen, because we can run Python code remotely, transparently. Zini
-was also especially careful about creating a simple API.
+was also especially careful about creating a somewhat simple API.
 
 The biggest flaw is that it is basically just a prototype with limited
 documentation and no stability promises. It's not exactly clear how to
 write new actions, for example, unless you count [this series of blog
-posts](https://www.enricozini.org/blog/2021/transilience/use-ansible-actions-in-a-script/).
+posts](https://www.enricozini.org/blog/2021/transilience/use-ansible-actions-in-a-script/). It might also suffer [second-system syndrome](https://en.wikipedia.org/wiki/Second-system_effect) in the
+sense that it might become also complicated as it tries to replicate
+more of Ansible's features. It could still offer a good source of
+library items to do common tasks like install packages and so on.
 
 ### spicerack and cumin
 
 The Wikimedia Foundation (WMF, the organisation running Wikipedia)
-created a set of tools called [spicerack](https://github.com/wikimedia/operations-software-spicerack). It is a framework of
-Python code built on top of [Cumin](cumin), on top of which they wrote a
-set of [cookbooks](https://gerrit.wikimedia.org/r/plugins/gitiles/operations/cookbooks) to automate various ad-hoc operations on the
-cluster.
+created a set of tools called [spicerack](https://doc.wikimedia.org/spicerack/master/) ([source code](https://github.com/wikimedia/operations-software-spicerack)). It is
+a framework of Python code built on top of [Cumin](cumin), on top of which
+they wrote a set of [cookbooks](https://gerrit.wikimedia.org/r/plugins/gitiles/operations/cookbooks) to automate various ad-hoc
+operations on the cluster.
 
 Like Fabric, it doesn't ship Python code on the remote servers: it
 merely executes shell commands. The advantage over Fabric is that it
 bridges with the Cumin inventory system to target servers based on the
 domain-specific language (DSL) available there.
 
-It is also very WMF-specific, and probably would be useless outside of
-that context. It does have good examples of how Cumin can be used as a
-library for certain operations, however.
+It is also very WMF-specific, and could be difficult to use outside of
+that context. Specifically, there might be a lot of hardcoded
+assumptions in the code that we'd need to patch out (example, [Ganeti
+instance creation code](https://github.com/wikimedia/operations-software-spicerack/blob/1a9aa78197d983b87756da38fe5a6414c16ef866/spicerack/ganeti.py#L229), which would then therefore require a
+fork. Fortunately, [spicerack has regular releases](https://github.com/wikimedia/operations-software-spicerack/tags) which makes
+tracking forks easier. Collaboration with upstream is possible, but
+requires registering and contributing to their [Gerrit instance](https://gerrit.wikimedia.org/)
+(see for example [the work anarcat did on Cumin](https://gerrit.wikimedia.org/r/q/owner:anarcat%2540debian.org)).
+
+It does have good examples of how Cumin can be used as a library for
+certain operations, however.
+
+One major limitation of Spicerack is that it uses Cumin as a
+transport, which implies that it can only execute shell commands on
+the remote server: no complex business logic can be carried over to
+the remote side, or, in other words, we can't run Python code
+remotely.
 
 ### Other Python tools