revert: JoinControllers system.conf configuration

[jackfrancis]

Reason for Change:

Reverts #605. Java does not like a joined cgroup configuration:

$ sudo ls -la /sys/fs/cgroup/
total 0
drwxr-xr-x 10 root root 340 Apr 18 20:06 .
drwxr-xr-x 10 root root   0 Apr 18 20:06 ..
dr-xr-xr-x  6 root root   0 Apr 18 20:06 blkio
lrwxrwxrwx  1 root root  50 Apr 18 20:06 cpu -> cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
lrwxrwxrwx  1 root root  50 Apr 18 20:06 cpuacct -> cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
dr-xr-xr-x  7 root root   0 Apr 18 20:06 cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
lrwxrwxrwx  1 root root  50 Apr 18 20:06 cpuset -> cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
dr-xr-xr-x  6 root root   0 Apr 18 20:06 devices
dr-xr-xr-x  3 root root   0 Apr 18 20:06 freezer
lrwxrwxrwx  1 root root  50 Apr 18 20:06 hugetlb -> cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
lrwxrwxrwx  1 root root  50 Apr 18 20:06 memory -> cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
lrwxrwxrwx  1 root root  50 Apr 18 20:06 net_cls -> cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
lrwxrwxrwx  1 root root  50 Apr 18 20:06 net_prio -> cpu,cpuacct,cpuset,net_cls,net_prio,hugetlb,memory
dr-xr-xr-x  3 root root   0 Apr 18 20:06 perf_event
dr-xr-xr-x  6 root root   0 Apr 18 20:06 pids
dr-xr-xr-x  2 root root   0 Apr 18 20:06 rdma
dr-xr-xr-x  6 root root   0 Apr 18 20:06 systemd

Java tries to read the memory cgroup to understand what limits are set on it. Java does not currently understand the single hierarchy configuration this changed made and is unable to read the imposed memory limits, instead it falls back to just reading the system memory.

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[acs-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jackfrancis

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [jackfrancis]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[mboersma]

Should we remove parts/k8s/cloud-init/artifacts/system.conf as well?

Otherwise, lgtm.

[cpuguy83]

Can you update the commit message to include details on what java does not like and why java matters?
This makes it easier to understand later.

Basically, something like this:

Java tries to read the memory cgroup to understand what limits are set on it. Java does not currently understand the single hierarchy configuration this changed made and is unable to read the imposed memory limits, instead it falls back to just reading the system memory.

--- EDIT ---

s/java does not matter/java matters/

[jackfrancis]

@mboersma yes, done

@cpuguy83 thanks, added

[codecov]

Codecov Report

Merging #1095 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1095      +/-   ##
==========================================
- Coverage   74.33%   74.33%   -0.01%     
==========================================
  Files         131      131              
  Lines       18260    18259       -1     
==========================================
- Hits        13574    13573       -1     
  Misses       3905     3905              
  Partials      781      781

[mboersma]

I think @cpuguy83 wanted to see that blurb in the actual commit message body. If we admin-merge or force-push, let's do add it there.