[vtadmin-api] Allow RBAC config file to be optional

[doeg]

The --rbac-config flag is required when running vtadmin-api. If omitted:

F1217 12:14:01.251523   31578 main.go:72] open rbac.yaml: no such file or directory

The local example provides a default rbac.yaml file here: https://github.com/vitessio/vitess/blob/main/examples/local/vtadmin/rbac.yaml

However, it might be more ergonomic + explicit if Vitess operators could either:

• Provide an --rbac flag and an --rbac-config file, or
• Provide a --no-rbac (or --rbac=false) flag to explicitly opt out of using RBAC.

[setassociative]

I was reading the related backscroll with jakon and had the thought that defaulting allow-all when no rbac config flag is convenient but allows failure in an unsafe way: I can imagine fucking up a chef flag -> not passing an rbac flag -> opening write actions to the world.

Still extremely into easy allow-all option but we should make it opt-in under --no-rbac or similar.

[notfelineit]

A clarifying q, does that mean we're either saying 1) must pass in rbac config or 2) must explicitly pass --no-rbac to default to all?

[jakon89]

@setassociative +1 for --no-rbac
Anyway, unknown flags aren't allowed so its unlikely that scenario is possible:

adam@local ~ % docker run vtadmin:latest --rbac-confi /non-exisiting-file
ERROR: logging before flag.Parse: E1217 18:05:40.620713       1 syslogger.go:149] can't connect to syslog
Error: unknown flag: --rbac-confi
Usage:
  vtadmin [flags]

[setassociative]

@notfelineit sorry, to be more explicit: I'm suggesting you must pass in --rbac flag + config file or --no-rbac. Basically the caller needs to be explicit about how they want rbac to work in either case

@jakon89 so when constructing args to set up vtadmin there is the error where you typo the arg and it's safe as you point out. I'm more worried about a scenario where it gets omitted entirely for whatever reason and I'd rather fail hard and fast in that situation

[doeg]

This sounds great. I updated the issue description to specify an explicit --rbac or --no-rbac flag (instead of "failing open" if an RBAC config file is not provided).

[notfelineit]

This issue is being addressed here: #9972

[notfelineit]

Merged #9972! Closing this issue.