On 2018-04-26 16:04, John Florian wrote:
On 2018-04-25 04:53, Lennart Poettering wrote:
There have been requests in improving the cycle breaking algorithm,
but not much has been done in this area, since it's not clear what can
be done. Ultimately it's just polishing a broken situation, and
the better way out is to fix things properly, i.e. just correct the
cycle in the dependencies in the first place.
Having been the author of numerous custom services that are intended
to wedge into those provided by systemd/Fedora I've faced resolving
these several times and I've never felt all that competent at the
task. Lennart, you were immensely helpful on one occasion by pointing
me to `systemctl show FOO` but even then hunting the problem down was
far from simple (for me). I've done the dot/graphviz thing and found
it just as useless to me as when I've tried applying it to Puppet's
ordering/dependency looping. I'm not blaming those tools (or systemd)
because I'm well aware much of the problem is my inability to use them
effectively. The graphs always seem to be overly simple and revealing
no problem or overly detailed and obscuring the problem. Compound
that with "an arrow pointing this way means what exactly?"
Is there anything else that could be done to make hunting these loops
down easier? Is there an example of any product that has a similar
situation where they excel at helping the developer? Or are we
already there and I just need more practice? I'm sure part of my
struggle is just not encountering these very regularly and integrating
into much that I'm only partly familiar with, but the result is the
same, trepidation and loathing.
Since I hate to grumble w/o so much as offering any possible
suggestions... It seems like it might be helpful to have something like
`systemctl show` but only dumping the properties used for ordering and
dependencies. Ideally, only ordering OR dependencies as the case
warrants and for all units involved, but only those units.
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