If a connection hangs for too long in ApiListener#NewClientHandler(),
ApiListener#AddConnection()'s Timeout calls boost::asio::basic_socket#cancel()
on that connection to trigger an exception which unwinds
ApiListener#NewClientHandler(). Previously that unwind could trigger a Defer
which called boost::asio::ssl::stream#async_shutdown() which extended the hang.
Normally if for some reason an ack comment still exists on a checkable not
acked anymore, still clean it up. But while replaying log config objects
incl. ack comments come before check results and acks. I.e. 1) ack comment,
2) DOWN check result and 3) ack. Not 1) DOWN check result, 2) ack and 3) ack
comment. So the checkable is temporarily not acked, but already has the ack
comment. In this case the DOWN check result which is older than the ack
comment shall not clean up the latter.
Traditional behaviour was to regard all dependecies as cumulative (e.g., the parent considered unreachable if any one dependency is violated), commit ed5892238916ab667a4c9d904bd73acd3ed162f2 made all dependencies regarded redundant (e.g., the parent considered unreachable only if all dependency are violated). This may lead to unrelated services (or even hosts vs. services) inadvertantly regarded to be redundant to each other.
Most importantly, applying the explicit "disable-host-service-checks" dependency described in the "Monitoring Basics" chapter will defeat all other dependencies.
This commit introduces a new "redundancy_group" attribute for dependencies.
Specifying a redundancy_group causes a dependency to be regarded as redundant only inside that redundancy group.
Dependencies lacking a redundancy_group attribute are regarded as essential for the parent.
This allows for both cumulative and redundant dependencies and even a combination (cumulation of redundancies, like SSH depeding on both LDAP and DNS to function, while operating redundant LDAP servers as well as redundant DNS resolvers).
This commit lacks changes to the tests.
master before #9627 (a0286e9c6):
<1> => namespace n { x = 42; x = 42 }
^^^^^^
Constant must not be modified.
<2> =>
HEAD of #9627 (24b57f0d3):
<1> => namespace n { x = 42; x = 42 }
null
<2> =>
if caused by dependency or check period.
Now as long as any of the above causes check skips
next check and next update will be up-to-date in Icinga DB,
so the checkable won't slide into false positive overdue.
This was accidentally broken by #9627 because during config sync, a config
validation happens that uses `--define System.ZonesStageVarDir=...` which fails
on the now frozen namespace.
This commit changes this to use `Internal.ZonesStageVarDir` instead. After all,
this is used for internal functionality, users should not directly interact
with this flag.
Additionally, it no longer freezes the `Internal` namespace which actually
allows using `Internal.ZonesStageVarDir` in the first place. This also fixes
`--define Internal.Debug*` which was also broken by said PR. Freezing of the
`Internal` namespace is not necessary for performance reasons as it's not
searched implicitly (for example when accessing `globals.x`) and should users
actually interact with it, they should know by that name that they are on their
own.