snapshot file tracks the snapshot directory. when app gets deleted,
the cleaner will remove the upstream snapshot directory when it runs.
cache files are used in rsync logic to track what was uploading into
snapshot in the previous run without needing to rescan upstream.
this has many advantages:
* easy to deliver the updateInfo via the apps object
* after updating, the task can clear it
* when apps are deleted, the info is automatically gone
otherwise, it's a mess of deps between apps/updater/apptask/rest routes
box update info is still in a file
Currently, we allocate 50% as RAM and 50% as swap. The manifest is
usually quite conservative on memory values. This means that we set
up a system where the app is applying memory pressure almost immediately.
This then swaps things randomly and increases cpu usage (kswapd shows
up in the profile).
To rethink the whole situation: we should not cap apps with a swap limit at all.
The memory hard limit is what is important. By redefining memoryLimit , we are
doubling every container's memory and it's good that we over allocate this.
docker is using a extra udp port for every container. when there is
a lot of containers, a lot of random udp ports get used up. this causes
problems when installing apps that require contiguous port ranges
Previously, the du plugin was collecting data every 20 seconds but
carbon was configured to only keep data every 12 hours causing much
confusion.
In the process of reworking this, it was determined:
* No need to collect disk usage info over time. Not sure how that is useful
* Instead, collect CPU/Network/Block info over time. We get this now from docker stats
* We also collect info about the services (addon containers)
* No need to reconfigure collectd for each app change anymore since there is no per
app collectd configuration anymore.
initially, i tried to put this in the current value field but that
is TEXT and has a size limit of 64K. TEXT also stores things with
character encoding, so we have to stash it as base64
