Use exec in the CLI shell scripts to prevent new process creation

[AMoo-Miki]

Description

OSD 2.6 in prior used exec in the CLI scripts to invoke node; this was removed when use_node was introduced. This change reintroduces exec which will prevent new processes from being created.

exec executes a command that completely replaces the current process where the current shell process is destroyed. When you exec a command, it replaces bash entirely — no new process is forked, no new PID is created, and all memory controlled by bash is destroyed and overwritten (ref). This is useful for when the bin file calls use_node who then calls node; instead of having 3 PIDs to check for health, 2 of which will be doing nothing, exec allows use_node to replace the bin script and then node to replace the use_node, leaving us with just one PID.

Check List

• All tests pass
  • yarn test:jest
  • yarn test:jest_integration
  • yarn test:ftr
• New functionality includes testing.
• New functionality has been documented.
• Update CHANGELOG.md
• Commits are signed per the DCO using --signoff

[codecov-commenter]

Codecov Report

Merging #3955 (d59ea7e) into main (574f119) will decrease coverage by 0.04%.
The diff coverage is n/a.

❗ Current head d59ea7e differs from pull request most recent head 35f2e6d. Consider uploading reports for the commit 35f2e6d to get more accurate results

@@            Coverage Diff             @@
##             main    #3955      +/-   ##
==========================================
- Coverage   66.46%   66.43%   -0.04%     
==========================================
  Files        3229     3229              
  Lines       62091    62068      -23     
  Branches     9607     9599       -8     
==========================================
- Hits        41269    41234      -35     
- Misses      18511    18530      +19     
+ Partials     2311     2304       -7     

Flag	Coverage Δ
Linux	66.37% <ø> (-0.04%)	⬇️
Windows	66.38% <ø> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

see 19 files with indirect coverage changes

[seraphjiang]

@himsgupta1122 @ZilongX @zhyuanqi FYI

[seraphjiang]

Thanks @AMoo-Miki for the change to unblock downsteam usage. Maintainers, could we quick review and approve it. it is critical, could we backport and add to 2.7 release

cc: @seanneumann @bbarani @zelinh

[joshuarrrr]

This change reintroduces exec which will prevent new processes from being created.

There's no information provided here about why this is necessary or beneficial. There should be a linked issue that describes the problem and or regression.

[seraphjiang]

the exec removal change the OSD launch process behavior, it has impact to the downsteam customer which consume OSD during launch. It is very hard to test since there is not test cover that.

will leave to team to decide if should add such change to break change list

This change reintroduces exec which will prevent new processes from being created.

There's no information provided here about why this is necessary or beneficial. There should be a linked issue that describes the problem and or regression.

[ananzh]

I think this is from the discussion that we had in node 18 PR that exec could allow the new process keeps the same process ID as the original shell process. This can make process management easier, as you don't need to keep track of a new process ID. If I am wrong, correct me.

[AMoo-Miki]

Will merge this despite the Cypress tests failing as they cannot be related.