Trick #3 – What Do I Have Permissions For?

Ahoy, There!

This is just one blog post in an ongoing series about fun things you can do with the Kubernetes CLI, kubectl. We have a whole bunch of these over on our Silly Kubectl Tricks page. Also don’t forget to checkout out the video series on YouTube!

Stretching as far back as version 1.8 (in September of 2017), Kubernetes has supported a fine-grained access control mechanism called RBAC. Nothing gets done via the Kubernetes API that isn’t governed by some sort permission or another, and there are a lot of them.

Couple that with per-deployment service accounts, named user access credentials, and project-specific namespaces, and you’ve got the makings of a complex authorization scenario.

At times, you’ll wonder precisely which permissions you, or a service account you use, have been granted – that’s when you should reach for kubectl auth can-i.

To see everything you can do:

$ kubectl auth can-i --listResources                                       Non-Resource URLs   Resource Names   Verbs
*.*                                             []                  []               [*]
                                                [*]                 []               [*]   []                  []               [create]    []                  []               [create]
                                                [/api/*]            []               [get]
                                                [/api]              []               [get]
                                                [/apis/*]           []               [get]
                                                [/apis]             []               [get]
                                                [/healthz]          []               [get]
                                                [/healthz]          []               [get]
                                                [/livez]            []               [get]
                                                [/livez]            []               [get]
                                                [/openapi/*]        []               [get]
                                                [/openapi]          []               [get]
                                                [/readyz]           []               [get]
                                                [/readyz]           []               [get]
                                                [/version/]         []               [get]
                                                [/version/]         []               [get]
                                                [/version]          []               [get]
                                                [/version]          []               [get]

You can also just ask the API to see if a given action is allowed:

$ kubectl auth can-i get pods -n default
$ kubectl auth can-i get pods -n kube-system
$ echo $?

These commands exit 0 if such access would be allowed, and 1 if not, making them handy for use inside of shell scripts or other automation:

if ! kubectl auth can-i create secrets; then
  echo >&2 "You cannot create secrets.  Please contact your k8s admin."
  exit 4
# etc.

Check out the Video!

Want more? Curious what happens when an unprivileged ServiceAccount is involved? Then check out the video and learn you some access control!

Spread the word

twitter icon facebook icon linkedin icon