What does this PR do?

Avoid suffixing with /1 when reading conntrack proc files.

In a docker container the proc_location is suffixed with /1 for net files.

But there is not need to suffix with /1 for conntrack files

Conntrack files always reside in /proc/sys/net/*. Commands executed inside a container:

root@ffcad4dd91a8:/# cat /host/proc/sys/net/netfilter/nf_conntrack_events
1
root@ffcad4dd91a8:/# cat /proc/sys/net/netfilter/nf_conntrack_events
1

Note: nf_conntrack_count has a different value inside a container. See additional notes below.

Motivation

User getting this error Unable to read /host/proc/1/sys/net/nf_conntrack_max

datadog [ AGENT ] 2019-06-25 02:04:46 UTC | DEBUG | (pkg/collector/py/datadog_agent.go:152 in LogMessage) | (network.py:463) | Unable to read /host/proc/1/sys/net/nf_conntrack_max. Skipping nf_conntrack_max metrics pull.

Additional Notes

It seems that some host conntrack stats are not available inside a container.

Inside container:

root@ffcad4dd91a8:/# cat /host/proc/sys/net/netfilter/nf_conntrack_count
0
root@ffcad4dd91a8:/# cat /host/proc/sys/net/netfilter/nf_conntrack_max
262144

On host:

➜  ~ cat /proc/sys/net/netfilter/nf_conntrack_count
24
➜  ~ cat /proc/sys/net/netfilter/nf_conntrack_max
262144

But it seems that nf_conntrack_count has a different value inside a container (the only one):
conntrack_metrics.txt

Review checklist (to be filled by reviewers)

• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached
• Feature or bugfix must have tests
• Git history must be clean
• If PR adds a configuration option, it must be added to the configuration file.