* Implement commonalities and linux support for ARP collection
* Add ARP collector to fixtures and run as part of e2e tests
* Bubble up scanner errors
* Use single return values where it makes sense
* Add missing annotation
* Move arp_common into arp_linux
* Add license header to arp_linux.go
* Address initial feedback
* Use strings.Fields instead of strings.Split
* Deal with scanner.Err() rather than throwing away errors
* Check for scan errors in-line before interacting with the entries map
* Don't interact with potentially empty text from scan
* Check for scan errors outside the scan loop
* Add comment about moving procfs parsing
* Add more direct comment
* Update initialism style to match go style guide
* Put function args on the same line
* Add TODO in front of comment about procfs extraction
* Guard against strings.Fields returning an empty slice
* Be more defensive about ARP table format and use upcase more broadly
* Enable the ARP collector by default
* Add ARP collector to the README
* Remove 'entry'
It is tested on FreeBSD 10.2-RELEASE and Linux (ZFS on Linux 0.6.5.4).
On FreeBSD, Solaris, etc. ZFS metrics are exposed through sysctls.
ZFS on Linux exposes the same metrics through procfs `/proc/spl/...`.
In addition to sysctl metrics, 'computed metrics' are exposed by
the collector, which are based on several sysctl values.
There is some conditional logic involved in computing these metrics
which cannot be easily mapped to PromQL.
Not all 92 ARC sysctls are exposed right now but this can be changed
with one additional LOC each.
This collector exposes most of the useful information that can be found
in /proc/drbd. Sizes are normalised to be in bytes, as /proc/drbd uses
kibibytes.
This change adds a new collector called "nfs" that parses the contents
of /proc/net/rpc/nfs and turns it into metrics. It can be used to
inspect the number of operations per type, but also to keep an eye on an
extraneous number of retransmissions, which may indicate connectivity
issues.
I've picked the name "nfs", as most operating systems use "nfs" for the
client component and "nfsd" as the server component. If we want to add
stats for the NFS server as well, we'd better call such a collector
"nfsd".
We seem to have a small number of Linux servers here that have lines in
/proc/mdstat that cannot be parsed by the node exporter, due to them
containing attributes that are not matched by the regular expression
("super 1.2").
Extend the regular expression to skip this data, just like we do for all
of the other status lines.
